HANDYBOB RV SOLAR POWER THAT WORKS
BOONDOCKING WITHOUT A
GENERATOR
March, 2009 Last
edited August 15, 2009
Clean those panels!
FIRST: There are several HandyBob’s in the world. Do not confuse
me with those that post about anything except solar power & living
off-grid.
SECOND: This may be confusing, but this blog was created using
several articles I had written over the past few years. You will note that
they are dated. My goal in setting this blog up was to have all of my
solar articles here where they would be easily accessible. When you read
in one of these that you can e-mail me & I will send you the RV Battery
Charging Puzzle, please understand the context. That statement was made in
that particular article posted on a discussion forum some time ago. The RV
Battery Charging Puzzle is included herein, so just keep reading and you will
find it.
By clicking on the Blog title, you can access other posts, such as
“About”.
Now for the story:
This all started in the fall of 2000 when Bob & Norene sold the house in
Montana, moved into a 26ft travel trailer with Kodi the American Eskimo wonder
dog & set out to tour America. We had previously owned several RV’s
but had never stayed a single night in an RV park until having traveled all the
way to Wisconsin. I remember standing in front of the electrical pedestal
in our first RV Park and thinking “so that is what the 30 amp RV plug is
for”. That first year of traveling all the way around the USA we spent as
much time as we could in forest campgrounds, national & state parks and
anywhere else we found that was cheap or free, but at least half of the time we
were plugged in and hooked up in RV parks. We found that the solar panels
I had installed on the roof of the trailer were not capable of keeping up with
our electrical needs and every time we went off grid it was only a matter of
days before our batteries were dead again & we had to plug in. We
quickly figured out that living in RV parks was not for us. Jammed in wall
to wall and having a nice view of the neighbor’s sewer hose is not the life we
had in mind when we contemplated early retirement. So I didn’t give up and
I did eventually figure out how to make our electrical system work.
Over the next three years we evolved from campers into full time
RV’ers. In the summer of 2002 we traded up to a 31ft fifth wheel suitable
for full timing and committed to the nomadic lifestyle. This rig came with
a solar system already installed, to which I added the two solar panels from our
old trailer. When we unplugged and headed south that fall we discovered
that the system installed in it worked even worse than one we had in our first
trailer. That was when I got serious about trying to make solar power
work. Unbelievably, we had 345 watts of solar panels and yet we couldn’t
run anything more than our lights without having our batteries go dead.
The system in this rig was supplied by the most respected RV solar dealer there
is, the one who wrote the book, who used to conduct seminars at the Escapades
and has the nickname; “grandfather” of RV solar power. It took me a while,
but I figured out this guy was clueless about how to make solar power
work. When I replaced the worthless controller he supplied with a decent
one, moved it to near the batteries and replaced the #10 wire he had supplied
with #6 that I rerouted to make it shorter was when we started to evolve from
being campers who were afraid to use our lights into “power hogs” that
successfully run every electrical appliance we own on battery power supplied
exclusively by our solar panels. That was the last time we stayed in an RV
park and we never did buy that generator. I will admit that having a
generator would have been nice a few times when forced to park under trees or
enduring several days of rain, but now that we spend our time only in the west
we are happy that we never bought one. Thanks to having more solar panels
than we need, we don’t need a generator. We are planning to build a small
off-grid home in the next few years and while a used propane generator out of a
motor home is on my shopping list, it is way at the bottom. We won’t need
it until we are using electrically powered refrigeration. I can run all
the power tools needed to build that home with the solar power already on our
RV. This is not conjecture; it is fact. I know this is possible
because I have done just that for a friend with an off-grid cabin that I
finished using this solar power and I never once started his generator.
I am a fairly smart guy, but not a genius, who retired from the electrical
engineering and electrical product sales businesses. I just knew that we
didn’t need to waste our money on a noisy generator and that those amps I saw on
the solar charge controller should be enough to run our camping type of life
style. As I struggled with this problem and when I finally did figure it
out I tried everywhere we went to help others who were struggling with the same
problem. The number of businesses selling solar panels and the number of
the owners of RV’s with solar panels who did not know how to make solar power
work has astounded me. Anybody who has spent thousands on something that
does not work is generally very defensive and will usually start arguing instead
of listening. I had to give up trying to reason with people and write
something that I could hand to them and then walk away. My “RV
BATTERY CHARGING PUZZLE” documents my experience. I wrote this out of
frustration. It started with six pages of why what you have does not work
and evolved into a rant on the state of the RV manufacturing and RV Solar
industries. This is all brutally honest and completely true. Anyone
who tells you otherwise doesn’t know what he is talking about. This is
aimed at the frustrated, technologically challenged and budget minded RV owner
who needs basic education about battery supplied electrical power. It was
not written for peer review and I will not respond to technical nit picking
criticism. It was also not written for profit.
The responses I have received from folks who have read my ranting run the
gamut from over the top appreciation to arguments. A couple of the
“professional” solar installers have contacted me and complained, but they can
go pound sand. I have replaced #10 wires that they had both installed on
three & four panel systems that did not work. When asked why I have to
be so negative I respond with “What would you have me do, when the situation
really is this bad and trying to be nice & polite about it failed
miserably?” I tried to reason with several of those “professionals” and to
work with them rather than against them, but most just don’t get it. You
are free to stick your head in the sand and deny the obvious, but I cannot.
I offer this free to the RV community as my way of trying to improve our
world. Please read the following statement very carefully: I DO NOT
SELL SOLAR EQUIPMENT. I have helped quite a few friends with repairs and I
have done a few installations, but I am not in the business of selling or
installing solar systems. I really just want to help. This might
change in the future if I could get a building put up from which I could run a
business, but for now I am dedicated to providing education only. Anyone
is free to copy & distribute this at no charge, but it is copyright
protected and publishing any portion of it for profit or personal gain is not
legal.
I am not a computer wizard and I do not have unlimited internet access, so a
friend has helped me set this site up. I will try to respond to questions,
but as time has gone on it is getting more and more difficult for me to keep
up. Yes, I have started working on an actual installation and design guide
with pictures & diagrams, that I would like to get paid for, but the
completion of this might be a ways in the future. I generally check e-mail
only on weekends so it can take days for me to reply to questions. With
that in mind, I can be reached at bobanene@gmail.com. However, please
do not send any questions unless you have read all of this information
first. I find that most questions I get have been answered in my articles
and I am starting to become a bit impatient with people that refuse to read them
first. I apologize for the length. I have received plenty of
criticism for that. All I can say is that every time somebody came up with
a new question, my writings got longer. You are free to ignore what is not
important to you.
By the way; I was named HandyBob by some friends who noticed that I was the
guy always helping to fix things for fellow boondockers. It was not my
idea. It started out as a joke, but it stuck. If you ask enough
fellow RV’ers, you will find someone who knows me and can tell you from personal
experience their opinion of my writings and my work. The following are
offered in chronological order as a way of explaining how I got to where I am
today, with the long article at the end.
_____________________________________________________________________________
THE BATTERY CHARGING
REVOLUTION, May 2007
(Posted on an internet discussion forum by HandyBob, spring 2007, in response
to a lot of misinformation posted by the uneducated.)
How about this revolutionary idea: If you want to know how to charge a
battery, try looking at the battery manufacturer’s recommendations instead of
believing the charger manufacturers. On Trojan’s web site you will find
that they recommend a 14.8 volt daily charge, not 14.4 like everybody
else will tell you. They also say to continue charging at that voltage
until a specific gravity test shows the battery to be full, not to shut the
charge off immediately or even early like most chargers operate.
Interstate will tell you similar things. The popular opinions on charging
AGM or other sealed batteries are also wrong. Every charger I have seen,
as well as every solar charge controller is set too low. I have heard
people say that this last .4 volts is insignificant, but they are very
wrong. Oh, you can charge at 14.4 volts if you are plugged into shore
power for days, but running the generator for a few hours or having your solar
controller shut off as soon as it reaches the set point does not work.
Then, the “professional” RV manufacturers and solar installers will use too
small or too long of wire and guarantee that the battery never sees enough
voltage to actually get charged. Plus, the Link meter has a factory
default full setting of 13.4 volts, so it tells you your batteries are charged
long before they really are. Why things are this way is a mystery to me,
but this is why most RV & solar systems do not work very well. You
would think that manufacturers in related industries would talk to each other,
but it does not appear to be the case. I get blank stares from the RV
solar dealers that I have asked about these facts, or they start to argue, so
the solution is not to be found with them. One guy (one of the most
respected RV solar dealers around) last winter actually told me that a
hydrometer was not a good way to check a battery’s charge. What an
idiot! He was lying so his installations would look better to the
uninformed and he would get fewer complaints. I had bought six controllers
from him in the previous few weeks and there he was denying the truth!
I’ll take my future business elsewhere.
When I found Trojan’s info was when I started to figure out how to make my
solar system work. I now charge my batteries to 14.8 volts for an hour
& then float them at 13.5 volts, unless my temperature sensor automatically
lowers or raises this. I have been full timing (mostly boondocking) for
seven years and boondocking exclusively for the past five years, never been
plugged in at all and we have NEVER owned a generator. (We also do not own
either an inverter charger or a pure sine wave inverter.) Our 345 watts of
panels runs everything we want and I do mean everything. Coffee maker,
hair dryer, toaster, waffle iron, the electric iron that my wife uses for
quilting, power tools like a table saw and big air compressor for powering
nailers that I am now using while working on a friend’s off-the-grid cabin
site. We have enough power that I can continue to work on cloudy
days. It snowed here in Montana two weeks ago and my reaction was to tip
the panels so the water would run off as the snow melted when the sun finally
came out. My Trojan T105 batteries are over five years old and last
winter while I was working on a friend’s solar system I disconnected my system
for four hours and ran jumper cables over to his abused batteries to try to get
them back in shape (it worked). After four hours of still running the
small loads in my rig and putting all of my charging into the friend’s batteries
my Link did not show 12.7 volts like everybody will tell you is full. It
showed 12.85 volts! THAT is a really charged and really healthy
battery.
Those of you with a roof covered with solar panels that cannot keep up with
your needs are not getting all of the power your panels could produce into your
batteries. Wire that is not way oversized will not efficiently transmit DC
power to your batteries. (Look up the history on Edison vs. Westinghouse;
there is a reason we don’t use DC power transmission.) Any charger that
tapers too early, including the latest “boost” controller is not really
charging. They are not boosting; they are shutting the power off. I
believe that the solar dealers who know about this will not tell us because the
profit motive in selling $700 panels is just too great. I would bet money
that 99% of the residential systems are also under wired and adjusted
wrong. There is a picture in the old Backwoods Solar catalog of a cabin in
the woods with the whole roof covered with panels that I love to use as an
example of a system that probably does not work. (They made big
improvements in their new catalog & that picture was removed.) I
believe that a small home should be able to run on 1000 watts or so of panels if
I can run my house on wheels with 345 watts. I have put 250 watts of
panels on this cabin that I am now finishing, with four batteries and it is
working great because I refused to use the #10 wire supplied by the solar
dealer, ran #6 and set the charger up to 15.2 volts (14.8 volts @ the
batteries). Of course you do have to live efficiently, but it’s not
that difficult to turn the lights off when you leave the room. One of my
friends runs his bus conversion, including a 22 cubic foot residential
refrigerator, the light in his kitchen and the TV that never seem to get turned
off with 800 watts of panels, and now that I helped him rewire & set it up
correctly, he finds that he never runs his generator and really didn’t need that
many panels. The solar dealer made a bunch of money off of him.
Unless people start to think for themselves and figure out that salesmen lie,
this situation will only get worse. (I used to be a sales rep, so I
know.)
The majority opinions on batteries & charging are wrong. I am
living proof of that and the fact that over 95% of the solar systems I have
evaluated do not work well also bear it out. Somebody once attacked me on
this forum and said that I should not say things about people that lead a more
“robust” life, as if sitting in front of a computer and responding to every
query, whether you know what you are talking about or not is more robust that
running my power tools on my solar power and actually accomplishing
something. So, don’t bother to attack me. I won’t respond. I
will continue to live by example and help anybody with an open mind that is
willing to listen. Send me your e-mail address and I will respond with a
16 page long rant titled “The RV Battery Charging Puzzle” that will tell you why
what you have doesn’t work and what you need to do to make it work. But be
patient, I usually only do e-mail on weekends and depending on the access,
sometimes not even that often.
__________________________________________________________
AS MANY AS YOU CAN SELL By
HandyBob….. June, 2007:
(Posted on an internet discussion forum in response to “Why are you so
negative?”)
Let’s see if I can explain my view of what is going on in the RV solar
industry by using an example from my former life. I was a lighting sales
rep in the commercial/industrial world. The first thing you need to know
is that lighting reps are viewed as one step down from used car salesmen and are
expected to be dishonest. I once attended a training school at one of the
factories, where they attempted to teach basic lighting design to former shoe
salesmen (a real challenge). My background was engineering, including
lighting design, so this was a waste of time for me, but it did prove
interesting. The instructor handed out a sample office plan with some
basic parameters listed and asked us to calculate lumens, foot-candles and the
number of light fixtures needed. He then asked “What is the correct number
of light fixtures for this office?” When we turned the hand out over, the
answer on the back was “The correct number of fixtures is as many as you can sell.” In
other words, take advantage of the customer’s lack of knowledge if you can and
make more money. I didn’t work for this factory for very long. Their
corporate policy conflicted with my views and I just couldn’t live with
it. There were plenty of other companies that took the view that the
correct number of light fixtures would be what would work well, making the
customer happy and that happy customers are repeat customers, so I resigned that
company and found another.
I am on the outside looking in, but I believe that if you were a fly on the
wall at some of the sales training going on by the major players in the solar
business today, you would find something similar going on. The correct
number of solar panels is “as many as you can sell”, and use your imagination to
find ways to sell them. Why would you take advantage of someone in an
motor home and convince him that he needs 800 or even more watts of solar panels
and a boost controller that would run a house, when you know he doesn’t need it
and that it will spend most of it’s time just floating the batteries and
shutting the power off? Or, why install wiring that is not capable of
carrying the voltage and/or not setting the voltage high enough so that the
energy a system is capable of producing never gets into a battery bank, so that
the customer comes back next year complaining that he just doesn’t have enough
power and you get to sell him more solar panels? Or, why sell
someone a boost controller that costs three times as much as another very
reliable & proven controller that would work just fine in the
application? Or, why sell someone a cheap boost controller and load it to
100% or even more, knowing that it will shut the expensive power the panels
produce off in an effort to protect itself from burning up, and so it will not
be boosting, no matter what the meter says?
These things are happening on a daily basis and the answer has to be either
“To make more money” or “because they don’t know what they are doing”.
Take your pick, but isn’t one is just as bad as the other? If this were a
safety issue, the government would have been involved long ago.
Last year down south where many of us full timer’s winter, one of the bigger
and more respected solar dealers became a dealer for the biggest manufacturer of
boost controllers. He still had a stack of the very reliable old
technology controllers in plain sight behind his counter (I bought five of
them), but if you asked for one he would immediately go into a very aggressive
pitch about the latest technology boost controller and tell you that “You won’t
be happy with that old one and will be wasting your money on it. It won’t
get all of the power your panels put out into your system. You’ll get 25%
more power with this new one. I just want you to be happy.”
(The factory says “up to” 25% because the truth is far less, but the dealers
seem to ignore that qualifier.) While he was making this pitch, his
installers were out in back, happily installing under wired systems with shadows
on the panels from vents & air conditioners and leaving the voltage at the
too low factory default level on every single one of them, so that the power
really wouldn’t get into the systems. These actions speak volumes to
me. I once tried to have a conversation with this guy about the Trojan
Battery Company’s 14.8 charge voltage recommendation that he was ignorant
of. He gave me a dumb look and said that the factory settings were close
enough. He also refused to stock the temperature sensors to go with the
controllers I had been buying. This dealer is not in the power generating
business, he is in the money generating business. None of the systems he
installs work to their true potential, and he has a good reputation.
Sad. Do you want me to tell you about the really bad dealers?
Before any of you says that profit is not a dirty word, think about what I
said. I didn’t accuse the guy of making a profit. I accused him of
being dishonest and cheating the customer in order to make more profit, which is exactly what he
is doing. There are many RV solar dealers doing business like this.
It is the rule, not the exception. As I have said time & time again,
if these dealers really knew what they were doing and believed in it, they would
be running both their home and their business on solar power. Has anybody
ever seen one?? I have not. Even the reputable dealers are on the
grid. I really wonder about that. I’m not in the business, but I’ve
been off the grid in an RV for seven years and do just fine without a
generator. I have had the same 345 watts of panels on our present rig for
five years and have figured out how to go from a worrier who was afraid to turn
anything on, whose batteries were never charged with those panels, to the guy
that has not been plugged in for over four years, who runs all his power tools
and whose wife runs her electric iron & sewing machine while watching TV on
rainy days. Figuring out how to do so proved to be very challenging and
took me several years, because I have never found a source for reliable and
truthful design information. I did this by rewiring three times, moving
the controller, buying a real meter and going through four different
controllers. Nobody in the business talks about voltage, when it has
proven to be the most important part of the puzzle. I have gotten bad
advice at every turn, wasting a lot of both time & money and this is what
has me so upset with the solar power industry. You can count the ones who
know what they are doing on the fingers of one hand and I think I’m being
generous.
My experience in evaluating, working on and adjusting dozens of systems in
the past three years tell me that there is indeed a great big difference in the
power that goes into the batteries if you turn the voltage up to 14.8 volts (at
the batteries, not at the controller) instead of leaving it at the factory set
14.2 volts, which usually nets under 13.5 volts at the batteries, resulting in a
50 or 60 % charge level when the full light is blinking. Most
manufacturers of chargers seem to have no idea how to charge batteries and do
not recognize what a big problem voltage drop is with even short wiring
runs. Plus, there is an even bigger difference to be made if you buy a
real charge controller that was designed to run a house instead of one of the
several little flush mount types that most everybody buys, that were really
designed to trickle charge one or two batteries. They all shut the power
off too soon. One company even brags about their “gentle finishing
charge”, which is their way of saying that they taper the power off before the
batteries are fully charged. It is the difference between a system working
and just “sort of” working. There are many RV’ers no longer
running generators who think I am a magician, but after spending years of
experimenting in figuring it out, I now believe it is just common sense.
Now, you can all have your discussions about this. I’m not going to
comment further. Any of you that disagree & can’t see what is going on
have your heads in the sand.
__________________________________________________________
RV BOONDOCKING WITH SOLAR
POWER, November 2007
The most frequently asked question: (by HandyBob)
Can I run __________ with solar power? You fill in the blank.
I’ve been asked everything & my answer will surprise you. If it is an
electrical appliance that you have in your house or RV, the answer is yes (including the RV air conditioner
up on the roof or even the heater). However, you have to buy the inverter,
batteries & solar panels to put the power back in & some things take a
LOT of power. That air conditioner would take at least two solar panels
& batteries for every hour you want to run it. I once read in a bus
conversion magazine that you need 2000 watts (about 20 panels) plus a generator to run a bus.
Obviously, that author was no solar expert. You tell me; where would you
put twenty panels & batteries on a bus, assuming you can afford them?
It is not practical to run
everything, even though it is
possible. On the other hand, a CPAP machine takes less than the
output of one solar panel, so it is an easy thing to power. Living on
solar power is a totally different challenge for some folks than anything they
have done before. People that are used to turning lights, TV &
computer on when they get up in the morning & leaving them on all day need
to think about whether this is really the life for them. If you are
financially able to spend the money, it is possible to live like that on solar
power, but the reality is that it takes a lot of money. A reality check is
in order. If you don’t have unlimited funds, you need to be willing to
compromise. One person I met with a five solar panel system that could not
keep up with her “needs” summed up her view by saying “I’m not going to
conserve. I need my 49” TV (an exaggeration) & I worked all my life so
I can live any way I want.” I have run into folks who need to turn ten
lights on to feel comfortable, while we are happy with two or three. Face
it; many folks who are not willing to change their life & do some conserving
would be better off in an RV park & hooked up. I believe that people
who want to run their generators all day and through the evening should do just
that. Parking fees are cheaper than running a generator, not to mention
how the majority of us out here feel about the noise & fumes.
In our RV home we have made a lot of little modifications (not all
electrical) that add up to a successful off-the-grid life. Some
examples: I cut a hole in the ceiling of our bathroom & added a
skylight, so we wouldn’t have to turn a light on every time we went in there to
wash our hands. We have the water supply to the toilet shut off, except
for a hand held sprayer for “you know what” and we save our dish washing rinse
water in a jug & use it for flushing. There is a water pipe next to
our shower that feeds back into our fresh water tank, so we can run the shower
water into it until the cold water in the lines is flushed out. We
replaced the big standard size kitchen sink that came in our rig with a small,
two compartment RV unit to help save water. I installed a bigger water
tank and reinsulated the entire bottom of the rig. I have added all kinds
of extra wiring & lighting modifications to help save power. We use a
propane “brick” heater instead of the furnace, which saves both electricity
& propane. Our furnace vents have been covered for years. Our
fifth wheel’s suspension has been jacked up 5” higher so we can get to real
boondocking places.
We have a 19” flat screen TV, not a 27” or bigger like many new rigs.
Our TV takes less than 3 amps, not the 10 or 12 like many of the TV’s I have
seen in those rigs. We also have one TV, not two. We CAN run this TV
all day if we want. It is about like running two 12V light bulbs.
This is how we are able to run all of the other appliances like the coffee
maker, toaster, electric iron, etc. and all of my power tools, without owning a
generator. Just to give you food for thought; Our TV can run for ten hours
on the same power that many folks would use by watching only a two hour
movie. We can run our waffle iron on that same amount of power. It
is a choice. We could run our rig with only one solar panel (we have 345
watts) if we gave up the appliances & tools and ran the TV only two or three
hours a day. In our view, we are not just “getting by”.
We can camp anywhere as long as we have sunshine every few days and
live a very comfortable life on very limited funds. We are happy to turn
the lights off when we don’t need them and we can truthfully say that our solar
power has paid for itself many times over (about once per year). Our
electricity is free and it falls from the sky in unlimited amounts. If
only water & sewer were so simple.
Anybody can “get by” with a lot less solar power than the dealers try to sell
them. Only you can decide how much effort you are willing to put into
conservation, or how much money you can spend if you are not willing to
conserve. Suit yourself, but believe me when I say that there is another
way.
___________________________________________________________
SOLAR POWER – LIVING BY EXAMPLE
DURING JANUARY 2008
(Posted on an internet discussion board by HandyBob)
We got up this cloudy morning after two cloudy days in a row boondocking out
in the Arizona desert to find the batteries at 12.3 V & the meter saying
-127 amp hours. We have been running whatever we want & watched TV,
plus a movie last night. I guess we’ll have to start the
generator. Wait, we don’t own one! So instead we ran the
coffee grinder, Mr. Coffee, toaster & TV & ran down to -150 AH.
Yea, we have a 19” TV, not a 27”, but those other things don’t take as much
power as the solar dealers tell you. Notice, I am typing this on a lap-top
that is plugged in. It also uses less power than you think. We are
currently charging at a net +2.5 amps, in the clouds, with the lap top plugged
in and a small inverter powering it. We could comfortably go for two or
three more days, but the forecast says clear tomorrow.
The important points here:
- Our system is designed, wired & adjusted correctly. Our
batteries were full three days
ago, not just nearly full (charged to 14.8V). The majority of the folks
you talk to that have solar power (and generators) don’t believe we are
actually doing this. Either their systems don’t work, or they don’t
understand battery power. The majority is misinformed. We have a
neighbor here with more solar power than we have, but who runs a generator
every single day. He believes it is the normal way to live and he
doesn’t want to discuss it. He is close enough too see our lights on,
knows that we have no generator & still believes the majority opinion and
the salesmen instead of the obvious truth. Aarrg!
- A $200 recording “smart” meter like a Trimetric 2020 or a Link is a necessity if you want to boondock on
battery power in an RV. It is the water level gauge for the batteries
& tells you the actual level of charge. This will tell you if your
charger is actually working (converters powered by generators do not) &
when to run it. Cover the volt meter with a piece of tape.
- If you want to go solar, you need to educate yourself. Going into
the average RV solar dealer and asking for advice is worse than asking an RV
dealer or truck salesman about weight ratings. Are those people living
in RV’s & off-the-grid??
- Three stage, non boosting charge controllers without meters that actually
work cost about the same as pretty, flush mounted non-working gadgets with
meters, bells & whistles. Controllers mounted at the batteries
work. Those mounted up inside any distance from the batteries and not
getting the full voltage to the batteries because of the voltage drop caused
by the wire do not work.
Voltage is more important than
amps, although you do need both.
- Your chances of getting a correctly wired & properly adjusted solar
system installed in Quartzsite (or anywhere else) are very low unless you know
what to ask for or have a big budget. Even then, you won’t find anybody
who wants to follow up with you & make sure it works. I just helped
a friend rewire his rig after it had been “fixed” and a panel that he didn’t
need added the prior week by one of those dealers. After they had rewired it
inadequately & left the controller 30 feet from the batteries, I measured
13.8 volts at the batteries while his controller was showing 14.7 volts.
Yes, I am angry. They either don’t know what they are doing or don’t
care. The end result is the same either way.
- You do not need as many solar panels as those dealers try to sell
you. I have many friends that can verify that. You have to find
those of us that are successfully running on solar
power. There are a few. You cannot blindly believe what someone
you have never seen tells you (like those folks on a discussion forum).
I know; you don’t know me either. The difference is that I’m talking
from seven years of full time off-the-grid boondocking experience and I’m not
trying to sell you anything. I’m trying to save you money.
__________________________________________________________
RV SOLAR POWER – THE SHORT COURSE
by HandyBob 12/08
If you want to solar power your RV & don’t have the ability or
inclination to install it yourself, the following is the minimum that you need to know.
Any RV solar dealer that argues with you on any of these points is
clueless. Unfortunately, I believe all of the dealers in Quartzsite will
fail this test, even the ones with the “good” reputation. I have seen
their work, repaired a lot of it, and I get mad every time I drive by & see
what is going on in their work bays. Consider buying your equipment on
line or mail order & then finding someone handy with wiring to help you
install it. Any good RV tech can do it, but you have to tell them where to
put it and the size of wire to use. I am NOT looking for work, so please
find somebody else. I do recommend Backwoods Solar as a good, honest
supplier. Phone 208-263-4290 – Catalogs are free and have a lot of good
basic educational info for the solar power wannabe.
1. If you really want to successfully depend on battery power install a
Trimetric 2020 battery monitor / recording amp hour meter (sometimes called E
meter). I have hooked up over a dozen of these & everybody loves
them. This is available for less than $200 and should add about $300
installed to the cost of a system. Installing this before you buy solar & learning
how to read it will show you how much power you actually use and help you size
your solar system for your needs instead of spending a fortune on panels that
some salesman tells you that you need, without knowing a thing about your
life. It will pay for itself. If the company you are dealing with
does not offer this meter or a similar one like the Link or the built-in one
that comes in the Blue Sky IPN-PRO remote and tries to tell you that you don’t
need it; walk away.
2. Buy a three stage
charge controller that is adjustable and set it as recommended
by the battery manufacturer
(14.8V if you have wet cell golf cart batteries). I know of only one RV
solar dealer that is doing this. This controller does not have to be an
expensive Blue Sky or Outback unit in order to work. Both the Morningstar
Tristar (my favorite) and the Xantrex C series non boosting “ugly box” units do
a better job of charging for less than $200 than any of the little fancy looking
flush mounted charge controllers with lights, bells & whistles that the RV
solar guys are pushing. Do not let anybody talk you into anything
else. The expensive Blue Sky Solar Boost 2000E is not a three stage unit and it reduces
the power that your solar panels produce before the batteries are full. A
three stage charger keeps charging after reaching the voltage set point. A
$110 Xantrex C-12 (12 amps, only one panel) will do a better job of actually
charging a battery until it is full. Buy an expensive Blue Sky or Outback
three stage controller if you have gobs of money, but it is not necessary and
not worth the expense on small systems. If the company you are dealing
with tries to tell you that you must buy the small MPPT (boosting) controller or
you are wasting the watts your panels produce; walk away. Seriously, he is
in the profit generating business, not the power generating business.
3. Buy the temperature compensation sensor option ($30). This
will raise the voltage when your batteries are cold, so they will get a better
charge & reduce the voltage when they are warm, to protect them from over
charging and venting too much electrolyte. If the company you are talking
to does not have the temperature sensors in stock or tries to talk you out of
it, they are clueless; walk away.
4. Insist on the charge controller being located as close to the
batteries as possible. In no case should it be even six feet away.
The voltage drop between it and the batteries will prevent your expensive power
from reaching your batteries & getting them fully charged. Also,
insist that the wire between the controller and the batteries be over sized, at
least one size larger than required by the amp rating in order to limit the
voltage drop to less than 1%. The wire from the roof to the charge
controller needs to be sized for a maximum of 3% voltage drop. The
overall drop, panels to charge controller needs to be close to 5 or 6%.
There are voltage drop tables in the manuals for the good controllers and
guess what; they are missing in those for the pretty ones that don’t work.
The voltage drop from the panels to the controller doesn’t hurt if kept to
a reasonable level, but from there to the batteries it is critical. #10 wire is not big. #4 is the correct size,
not overkill, for four panel systems and the dealers in Quartzsite don’t even
sell it, which should tell you something. If the guy trying to sell you a
system says that all systems have voltage drop & it doesn’t matter where in
the system it is; walk away.
5. Do not let anybody tell you that it is OK to have any shadows on your panels from
antennas, vent covers, air conditioners, etc. no matter how small. They
are setting you up for failure. Tiny shadows will reduce the power
produced by 25 to 50% and covering one square shuts most panels completely
off. Many of the solar guys are clueless about this. I have proven
this time & again to many folks. This is extremely
important! Again; JUST WALK AWAY!
__________________________________________________________
SINE WAVE INVERTERS by
HandyBob, November 2008
Well, I finally did it. I bought a sine wave inverter… a
Morningstar Sure Sine 300 to be exact. Why? Well, I hope I didn’t
succumb to the marketing hype. I have done just fine for about eight years off
the grid in an RV that never gets plugged in, powered totally with solar power
and NO generator, with modified wave inverters running everything from stereo,
TV toaster, coffee maker & microwave to Dewalt battery chargers and power
tools like a table saw. Morningstar because I am very, very impressed with
the Morningstar Tristar charge controller that I now own, plus the experience
that several friends who have the same controller have had.
When my second to last inverter (Xantrex X-power 400) started acting funny
& was putting out somewhere over 139 volts I took it to the dealer that sold
it to me for his evaluation. He said it was within specs (I don’t think
so, that is 20% over 115V) and then said “what do you expect from a $40
inverter?” I said that I expected that it shouldn’t blow up my $300 TV
& $200 stereo. Hmmm………….. That got me to thinking.
Not too long ago I got a phone call from a friend who had a story to tell
about one of his friends who had burned up not one, but two new stereos on his
modified wave inverter. Of course, both Sony & Yamaha blamed the
modified wave power. I really suspect that it was the piece of $&#T
inverter made by Xantrex that is at fault, but who can prove anything???
(Has anyone else noticed where Xantrex inverters are now manufactured?)
China, folks. So, I bit it off & spent nearly $300 to run my
electronics & battery chargers. What the heck, I can afford it &
maybe it really will work better.
So far I can see no difference. It doesn’t even draw much more idle
current. I suppose newer technology does make a difference. Over the
long haul, who can say?? I rest easier though and have faith that my TV
& stereo are in better hands.
__________________________________________________________
MORE SYSTEM PROBLEMS 2009 By
HandyBob Feb. 08
I have been operating under the assumption that enough education given to the
consumer would force the RV solar dealers into learning how to do things
right. This has worked to a small extent, because I know of one dealer
(but only one) who is now using the 14.8V charge set point as Trojan
recommends. The rest of them remain clueless & refuse to install
correctly sized wire or adjust the voltage correctly even when asked to.
They are so mired in the past by their lack of knowledge and conviction that
they know better, that the consumer cannot get a working RV solar system
installed even when he knows what to ask for. My definition of working is
putting all the energy possible into the batteries and charging them until they
are fully charged so the power is available whenever it is needed. Most RV
solar systems installed by “professionals“ do not work like this and most people
who have them are afraid to really use their electricity.
I just checked a system (late Jan. 2009) bought by an RV’er who talked to me
first and then went to the dealer armed with education. The dealer argued
with him on several points and the guy bought from him anyway. He was told
that they couldn’t install the #4 cables needed to keep the voltage drop under
3% because it wouldn’t fit in the connectors they use, so he is stuck with wire
only large enough for three panels, not the four or five that he wanted to have
the capacity for. Then he was told they always set controllers to 14.35 or
14.4V & that the correct 14.8V setting as recommended by the battery manufacturer is too
high. Isn’t that kind of like saying that a tire manufacturer who says to
put 80 lbs of pressure in a truck tire doesn’t know what he is doing and less is
better? Then they told him that they never fuse the input side of a charge
controller, even though it is a UL requirement in home solar systems and the
manual that comes with the Morningstar controller they installed says to do it
because the controller will alarm & shut down if you do not shut the input
power off before reprogramming voltage setting. Let’s not even talk about
the standard tilting bars that hold the panels up to maybe 40 degrees instead of
the optimum 50 degrees, the lack of a ground wire to the lug in the controller
and the fact that they hooked the negative wires up backwards in the
controller. All this at a cost of only $80 per hour. It would seem
to me that anybody who is getting paid that kind of money should be able to give
the customer what he asks for. There used to be a saying “The customer is
always right”. Well now even an educated customer who knows what he wants
can’t get it. Please; don’t support businesses that won’t give you what
you ask for. This guy should have just turned around and
walked away.
Then, there is the other system that I just checked (Feb. 2009) for some
folks that had a single panel system installed in Quartzsite. The
expensive flush mount, two stage MPPT controller was installed in the
refrigerator cabinet with 25 feet of wire between it and the batteries.
The dealer used #8 wire because they told him to wire it so that they could add
a panel if needed and they thought this was just great. Here is the
reality: First, the manual for the controller he installed says to use #6
wire for the length of wire used. I measured nearly a half a volt of drop
between the controller and the batteries. This was with the negative wire
not even going all the way to the batteries. (He tied it to the frame as
close to the controller as he could.) Then he set the controller to 13.8V,
which means the batteries will never see more than 13.4V in the middle of the
day when the amps are the highest. So, the batteries are going to be
running in the middle of their range and probably never get above a 70% charge.
This will lead them to sulfation & stratification problems and shorten their
life. This voltage drop is only 3%, which you would think is good, but it
is in the worst place in the system and when they decide that (of course) they
need more power and add that second panel, the voltage drop will double to 6%,
which will actually make things worse. Even if they set the controller up
to the recommended 14.8V, the batteries will still only see about 14V and they
will still never get fully
charged. Remember, you cannot just turn the controller up to 15.6V to
compensate because it will cause over voltage problems when the amps drop late
in the day on the days that you have charged by running the generator or driven
with the engine alternator charging. The solution is to simply move the
controller to a compartment next to the batteries. Of course, that
negative wire has to be extended to the new controller location. It would
have been a lot easier and not added any labor if it had been run next to the
positive wire like it should have been. This brilliant idea he came up
with to cut the expense of the negative wire does not agree with any accepted
wiring practices. The positive & negative wires are supposed to be run
together and twisted to limit radio frequency interference, but I suppose that
doesn’t matter as long as he gets away with it. The dealer will argue that
where the voltage drop occurs in the system doesn’t matter (I have had that
conversation), but if you take 6% away from the 17V+ the panels can produce, you
will see that about 16V will still get to the controller in its new location,
which will then regulate it down to the 14.8V that the batteries need and that
will actually get to the batteries thru a very short wire. It will also
provide the 15.5V needed for occasional equalizing, something that cannot be
done as the system was installed. Just by changing the location of the
controller, this system will charge the batteries all the way up and take care
of them so they will last. One little fact that I need to emphasize is
that the extra 6% in higher voltage getting to the batteries gives you six
percent more watts into the
batteries (and they keep talking about boost). By putting the
controller in the wrong location, he is robbing the system of power, as well as
ruining the batteries. By selling a two stage controller that tapers the
power off instead of continuing to charge like a good three stage controller
would, he is robbing the customer of even more power that his panel could
produce. His belief in the MPPT marketing is shutting the power off, not
boosting it.
This dealer is the most respected in Quartzsite, the one with the money back
guarantee, but his definition of a working system is not acceptable to anyone
who wants to be able to live on solar power. He has been installing
systems just like this for years and I keep showing people how to fix them after
they figure out that they are not working. One of my friends went back to
him & complained last year after I helped him fix a similarly installed
system, so he cannot say that nobody has ever told him about this problem.
I also had a conversation with this dealer two years ago about Trojan’s 14.8V
recommended charge setting and he is still mired in the past and his mind is
made up that Trojan is wrong about how to charge their own products. He
also still does not install temperature compensation and we had that
conversation more than once. Why do the factories build this capability
into their controllers if it is not needed? Is this dealer actually
stupid? Or, do you suppose he is doing what he does on purpose, especially
the panel installations of his that I keep seeing with shadowing problems,
because people who need more power go back and buy more expensive solar panels
and guess what; his price is the highest in the country! Then, when the
batteries don’t last because of constantly being undercharged, he gets to sell
new batteries, too. There has to be a profit motive here! By the
way, the expensive systems they install with a big MPPT controller close to the
batteries do appear to work, but are inefficient because of voltage drop in the
wiring ahead controller that needs all the voltage it can get in order to
provide that magic boost. #8 wire is not big. Every extra bit of
voltage that gets to these MPPT controllers helps them work better. However, I
am still convinced that they are a waste of money and do not provide nearly the
amount of boost claimed.
Now you know why I refuse to do business with or even set foot in most of the
RV Solar dealers and why I recommend Backwoods Solar as an honest
supplier. I have started taking pictures of the problems I find. I
sure wish I had started doing this a long time ago! These pictures are
going to start to become very embarrassing for a few RV solar dealers. A
lot of you folks out there need to install a Trimetric meter and then hot foot
it back to the dealer & demand either your money back or free system
repairs, using the meter and the information that comes with it to prove that
your system doesn’t work! For more information about the meter and
properly maintaining batteries take a look at bogartengineering.com (the
manufacturer of the Trimetric meter) & read the file about using the meter
& battery maintenance. My voice alone hasn’t changed much, but
if a few folks would do just what I am suggesting these dealers would be forced
to wake up and join the twenty first century.
__________________________________________________________
THE RV BATTERY
CHARGING PUZZLE Written in 2004
By Bob Shearer, AKA HandyBob, bobanene@gmail.com Last revised 3/2009
My wife and I are full-time RV boondockers. (No, we don’t live at
Walmart. They are not in
the boondocks.) We successfully run our fifth wheel’s electrical system on
batteries charged with solar power and do NOT own a generator. Contrary to
what you have probably read in other places; it is possible to run a coffee maker and
a toaster on battery power. The only time we have been plugged in for over
five years has been to run air conditioning or when we have been stuck for over
three days & covered with snow. No, we don’t act like we are plugged
in and leave everything on all the time and yes, we do have to conserve if the
sun doesn’t shine, but we still use the Mr. Coffee & watch a 19 inch TV for
several hours every day. I have a background in electrical engineering and
electrical equipment sales and have spent quite a lot of time and
experimentation in figuring out how to make an RV system work. It is different
from designing buildings. I have rewired my system three times, had three
different sets of batteries and five charge controllers. So, when I tell
you it is possible to run on your batteries, you can believe me. We do it. The folks in the RV
industry are not the people to go to when you need honest information.
Everybody you talk to has an agenda and you need to ask yourself what that
agenda is before you believe what they say. For instance, the RV
manufacturer, who is in bed with the RV park industry, will tell you that they
put in a battery charger, but he is lying to you about that (see converters), so
you will end up needing to be plugged in at an RV park. The solar panel
salesman might tell you to put in #12 wires, knowing that it is going to soak up
a lot of the power from your panels. He will also tell you that the charge
controller’s factory’s voltage setting is high enough, when in truth your
batteries will never get full at
that setting. That way you will go back to buy more panels in order to get
the same amount of power you might have if you had used #8 wire and set your
voltage up to the proper level, so he gets to make more money. The battery
salesman will tell you to buy more batteries than your charger has the ability
to maintain, so he can make more money. How can you tell if a salesman is
lying to
you?
His lips are moving!
My agenda? I am trying
to get back the peace and quiet we used to have during the evenings when we are
out camping and enjoying conversations or the sounds of nature around the
campfire. More and more these days what we are hearing is the drone of
generators, when they really are unnecessary except for cooking and occasional battery charging, which can
both be done at times that should not bother your neighbors. I’ll never
understand why so many people have to be told when running a generator is
inconsiderate. Many seem to think that any time they want power, 24 hours
a day, is acceptable. That is just fine if you don’t want to make new
friends, but most of us don’t want to be kept awake, woke up early or be forced
to listen to generators when we are trying to converse during meals, happy hour
or night time campfire. Even those “quiet” generators make noise when
several are running. You can charge in the middle of the day
when you won’t bother anybody and use power quietly during the evening.
There are already countless books and articles written about the technical side
of this problem, but none of them that I have read do an adequate job of
emphasizing the most important parts of the battery system puzzle. I am
supplying this information as a supplement, not replacement, to what is already
out there in the hope that I can help quiet things down and to educate my RV
friends so they don’t waste their money on things that don’t work. I
evaluate electrical systems, perform repairs and some solar installations, but
I’m not selling equipment, so I have nothing to gain if you listen to me, except
to live in a quieter world. I am not trying to sell you
anything.
Don’t jump to the usual conclusion. Although it would be nice if
everybody could, I am not telling anyone to spend thousands of dollars on solar
gear. Some of our best boondocking friends do not have solar panels and
they don’t run generators inconsiderately. I am saying that you need to learn how
to use and charge your
batteries. Think about this. Many of us RV’ers are
successfully running our TV’s, computers, etc. without running a generator all
the time, so it is
possible. Don’t assume that since you and your neighbor have your
generators running, everybody does. You would be very surprised at what is
going on in some of those RV’s while no noise is being generated. Here I
sit at my lap top, with the TV & several lights on. From outside you
can’t tell what I’m doing, but you can hear the two “quiet” Hondas that
are both about a quarter of a mile away. Running on batteries is cheaper
than having that generator running, burning gas & wearing out while it is
putting out a very small amount of power to run something like a TV or your
lights. I see folks running 2000 watt generators to power 50 watt loads all the
time. That is only 2 1/2% of the rating, and that is ridiculous. Do
you start your generator every time you run your seven amp (90 watt) water
pump? Yes, batteries wear out faster when you use them more, but they cost
less than fueling & maintaining a generator. On the other hand, they
last a lot longer if you charge them all the way up at least weekly. Why
do you have batteries if you’re not going to use them? You can charge your
batteries either by spending hundreds on a generator & some charging equipment, which you can run
as needed when it won’t bother your friends & neighbors or you can spend thousands on solar
equipment. Either way can work. Yes, you may need to spend a bit on
a small inverter to run that TV and you may need to do some wiring in your rig
to get enough power to it so it will work right, but this will cost less than
you think. Those of you that have tried to run your TV with a small
inverter plugged into a 12 volt outlet and failed because the inverter beeped
& shut down are the victim of voltage drop problems, not the wattage rating
of the inverter. You either need to run bigger wires from the battery to
the inverter or move the inverter close to the batteries and use a long 120 volt
cord to the TV. Voltage drop is not a problem on the 120 volt side.
(Ten times the voltage = 1/10 the amps = 100 times the distance.)
While I’d like to keep this simple, there are a few basics that you must
understand in order to make your system work. Here is my version of how DC
(direct current) electricity works. On one hand we have air pressure; on
the other hand electricity. If you want to air up a truck tire you force a
volume of air (cubic feet) into it with pounds per cubic inch (pressure) of air
until it is full. It is easy to get the first few cubic feet of air in;
you can even do it with a hand pump. The fuller it gets though, the more
pressure you need. You can’t get it up to 80 pounds unless your hose puts
out more pressure than that. An air hose with 75 pounds of pressure in it
will never fill a tire to 80 pounds. Batteries are not sponges that soak
up amps. They are a lot more like tires that need to be filled up with air
pressure. You need volts (pressure) to get the amps (volume) to go into
the battery. Unless you have enough volts to push the amps into the
battery, they just won’t go in. Trying to charge a battery with too few
volts is just like trying to air up a tire with too few pounds of
pressure. It just doesn’t get the battery all the way full. Then,
just like you can use the volume of air that comes out of an air hose to do
work, like run an air wrench, you can use the amps in a battery to run
electrical appliances. An amp hour is a way of defining power available or
used. It is like volume over time. If you want to run an appliance
it will take whatever number of amps for the period of time it runs and by
combining the two (amp hours), you get a way of defining the power you need to
store in a battery if you want to run that appliance at a later time.
Watts (volts times amps) is actually a more accurate way of defining power,
which is why the power companies bill you for watts or kilowatts, but it is much
easier for us to deal with this issue in a battery powered world by using amps
times hours and assuming an average of 12 volts, even though a healthy 12 volt
system is never really that low.
VOLTAGE: For the sake of simplicity, I am only going to talk
about the requirements of standard flooded wet cell lead acid batteries, which
is what most of us use. The major points apply to all types of batteries,
but the actual numbers will vary. It is very important for you to research
the charging requirements of your batteries if you are using any other type and
make sure that your charging system provides what they need, or you could end up
damaging them by over charging or never getting them fully charged, which will
also damage them. Battery manufacturer’s specifications say that a
standard 12 volt wet cell battery needs to be charged to between 14.4 to 14.8
volts and then held
there for some time before it will be fully charged. (The
Trojan battery company says 14.8
volts daily charge.) How long it takes to get the charge in depends on how
far it was discharged. Trojan says to keep charging until a hydrometer
test shows that the battery is charged and not one charger available today can
do this. A fully charged battery can then be maintained at a full state by
applying a 13.2 – 13.6 volts “float” charge. All of the talk about how
many amps a charger puts out means nothing. It is the volts (pressure)
that you need to push the amps (volume) into a battery. VOLTS,
VOLTS, VOLTS!! Also, the amps pushed into a battery at a higher voltage
contain more power than those at a lower voltage. Remember, volts times
amps equals watts, so amps pushed at 10% higher volts give you 10% more
watts. Therefore, the power stored in the upper range of a battery’s
charge is greater, so it is very important to get a full charge. Low
voltage DC is not easy to get through wire without losing power due to voltage
drop or resistance. It is huge problem in an RV. Use big wires and
short wiring runs to get around this. It is good practice to use one or
even two sizes bigger wire than recommended to limit voltage drop. This
charge voltage has to actually reach the battery, not just the output terminals
on a charger. If you cannot get your batteries up to 14.4 volts (14.8 is
better & faster) with whatever charging system you have and then keep them
there while pushing amps in for more than an hour or two, your batteries will
never be full.
BATTERY MONITORS: The RV industry has really let us
down. First of all, you can’t believe the little “idiot light” panel that
came in your rig. That thing is very optimistic and tells you the
batteries are full at 13.4 volts, when they are actually nowhere near it (14.4
volts). It works by looking at the voltage present on the wiring, which
will be much higher than the battery voltage while charging & much lower
than the battery voltage when running loads. If it says your batteries are
“full” while you are charging, you could be anywhere from 40% to fully
charged. People that run their generator until the idiot light says “full”
are only getting their batteries up to about 40 or 50%. They start their
evening at the point my system would get down to after a week of rainy days. Last, if the
monitor says your batteries are “fair” when you are not running anything, they
are DEAD. So, how can you tell if your batteries are really getting fully
charged? The most accurate way is to test the battery electrolyte with a
hydrometer. This is messy and not very convenient, but if you want to know
for sure this is what you have to do. The easy (but not as accurate) way
is to buy a cheap little volt meter and measure at any point in your rig (12
volt outlet, light or fuse panel) after the batteries have been resting for over
an hour. Both charging and
loading will cause false readings. A resting, full battery will test at “about” 12.7
– 12.8 volts. A resting, dead battery will test at 11.8
volts. Yes, that dead battery will still provide some power, but you are
destroying it by letting it get that low. That magic 50% level that the
battery manufacturers say you should stay above for good battery life is about
12.2 volts. Campers generally don’t get decent life out of their batteries
because they run them down too low and don’t keep them charged up, causing
sulfating and stratification. My first set of RV batteries lasted less
than two years. My current set is on its eighth year and just starting to
show signs of getting old.
RECORDING METERS: I used to tell people that the $200
“smart” amp hour meters like the Link are a toy that you really don’t
need. After all, your inverter remote or charge controller has a volt
meter on it, and many have ammeters, but if you think about where they are
connected you will realize that they don’t give you very reliable data.
So, I finally bit the bullet and installed a Link 10, and I have changed my
tune. You should buy one of these before you spend a dime on solar power.
Trying to run a battery system without a good meter is like driving a car with
no fuel gauge. You end up spending your time worrying and stopping to fill
up instead of driving. At a glance, we now know exactly where the
batteries are. We have discovered that most electrical appliances use a
lot less power than we thought and we now have confidence in our system.
We love to show off by inviting folks over for solar waffles for
breakfast. “Can we use the microwave for dinner? Well,
the meter says we are only 30 amp hours in the hole and we could go down as low
as two or three hundred before worrying, so go right ahead.” Or, “It’s
been raining for two days and we’re down 150 amp hours. Maybe we should
light the oven.” (We get quite a bit of power from our solar panels on
rainy days, so that 150 amp hours is reasonable, but you would never know it by
looking at a volt meter.) My wife gets quite a kick out of watching the
amp hours go down and then right back up again when she runs the iron or the
hair dryer on sunny days. This is very cool. Now, a caution or two
about these gizmos; My Link had a very weird idea of what a fully charged
battery is, because the default setting is only 13.4 volts, way too low.
It has an automatic charge coefficient calculator that jumped around so much in
my rig that it gave us very unreliable data. After playing with it for a
while, it works great set at 14.6 volts, 2% charging amps, 660 amp hours and 50%
use floor, and the charge coefficient locked at 94%. Every system will be
different. You do need to get technical here and get involved in the
programming, because the factory default settings are just designed to make you
feel good, not give you useful data (just like those RV battery monitors).
On the plus side, one of these tells you the voltage right at the battery
terminals and how much current (amps) is going in or out, and records the amp
hours used, something that tells you how well your system is actually working
and helps you figure how much energy any appliance actually uses. If you
have one of these, you don’t need the expensive remote readout that is optional
on the better solar charge controllers. We love our Link. The newer
Tri-metric 2020 meter (bogartengineering.com) is even better and is easier to
wire and program (I have installed over a dozen of them and everyone who has one
loves it). The instructions include an explanation of charger settings
that agrees with what I say above. Its percent of charge readout is all
most folks ever need to look at. I’ve seen a couple of problems with the
old Trace TM500. It connects with a phone cable to a printed circuit board
located at the batteries. I believe the problems I have seen are caused by
having that circuit board in a harsh environment like an RV battery compartment,
which in some motor homes is outside behind the wheels in the dust, water, slush
& worse.
Let me give you an example or two about how most appliances use a lot less
power than we thought:
Our water pump is labeled 7 amps, but it actually measures 2.9 amps (less
than half).
Our 19” wide screen LCD TV is labeled 40 watts, which calculates to about 4
amps on 12VDC, but it actually measures 2.7 amps, 30% less. Every TV I
have measured has been similar.
Our Mr. Coffee drip coffee maker is labeled 600 watts, which calculates to
about 60 amps on 12VDC, but it actually measures only 44 amps (maybe 450 watts)
and brews a 4 cup pot on only 7 amp hours, about twenty minutes of sun. We
run the toaster with ten amp hours, a bit over a half an hour of sun. The
labels are required by law, but there is no accuracy required. The label
has to show what the appliance will not exceed, not the actual energy use.
According to the usual chart in a solar catalog our bed warmer should take
about 20 amp hours, while we run it on less than a fourth of that. Of
course, we don’t set it on high.
They say standard refrigerators use about 150 amp hours per day, while a
friend’s energy star rated, but 22 cubic foot one runs on just over 100.
Small freezers use a lot less than you would think. If your system can run
one down in your cool RV basement during the cool winter days on the output from
less than two solar panels, then it will work just as well when the temperature
is warmer, but the charging days are much longer. The government required
label is based on a warm environment.
The CPAP machine with a humidifier that everybody seems to think requires a
generator running all night will run on less than 30 amp hours, the output of
less than one solar panel. Let’s see; a single cylinder gas engine that
might run out of fuel & die (or that your incensed neighbor might sabotage)
or a very reliable battery & inverter. We ran into one guy in a tent
who had figured out how to run his on one small car battery that he recharged
while driving with jumper cables. Use your brain folks.
Get a good meter first and you can learn how to manage your power needs,
running the generator only when and as much as you need to. Then if you
can afford it, you can size your solar system with facts instead of a salesman’s
high estimates designed to get you to spend more money. If you listen to
them you will be sizing your system for higher than true loads and then applying
a fudge factor above that, which can double the cost. Let’s see; buy a
$200 meter that will improve your life or another two or three $700 solar
panels. This is a no brainer.
You say that you can’t get
through the evening on your batteries? Most likely that means
that you aren’t starting the evening with fully charged batteries. You
might need new or even more batteries, but your basic smaller RV should run
through an evening on only one
battery, even if powering a small TV or stereo. Those of you with only two
golf cart batteries in your big rig should be able to run a 27” TV all evening
on less than 50% of your charge. 50% of 225 amp hours capacity, less a few
amps for lights, etc. or about 100 amp hours will run that 12 amp (150 watt)
load for over eight hours.
If you can’t do that, your batteries were not full at the start of the evening,
or you may be obsessing over a volt meter reading that is low due to having
loads running. Go back a couple of paragraphs. We go for days of rain in our rig while still
running the coffee maker, 19 inch TV and other normal loads, so I am getting
tired of people telling me they can’t get through just one evening without a
generator. You
can! You just have to figure out how to charge your batteries.
JUST WHAT IS A FULL BATTERY?? The general consensus on this
issue is not correct and this is
the primary reason that most RV electrical systems do not work very well.
The batteries in my rig show 12.8 volts after the sun goes down and
will usually show 12.5-12.7 after watching TV & running lights all
evening. I typically see 12.5-12.6 on the meter if I manage to get up
before the sun rises. These same batteries used to work like everybody
else’s before I figured this out, so this is fact, not opinion. My charger
works so well because it is set to get the batteries up to 14.8 volts and hold
them there for two hours before floating and since it is solar, it runs all day. It is so important to
get your batteries full because a 95% charged battery has 10% less usable power
in it than a 100% charged one, since you are trying to keep it in the top 50% of
its operating range (5% of full = 10% of 50%.)
BATTERIES: If you decide to buy new batteries, get the six
volt, golf cart type and run two of them in series to get 12 volts. I
can’t get into the complicated details here of why, but if you will do this, you
will get better than twice the life of the standard 12 volt marine battery and
around 20% more power. They are built heavier and work much better.
Be very careful about buying the new, high tech and expensive battery types
because they have different charging requirements, which vary by
manufacturer. Unless your charging equipment is adjustable, you could
damage those expensive new batteries by over or under charging them. I did
not say you shouldn’t buy them. I just said you need to be careful.
Get the battery manufacturer’s
charging specifications and pay strict attention to them. The charger
manufacturers are nearly all not
setting their equipment up for the voltage that the battery manufacturers
specify. The difference between 14.4 & 14.8 volts is not 3%.
That difference is nearly 20% of the charging range (12.2 to 14.8 volts).
That 20% makes a huge difference in how full the battery gets before the charger
shuts off. You can eventually get the batteries full by charging at 14.4
volts, but it takes hours, not minutes. We have related industries that
are not talking to each other and the outcome is that the majority of RV’s are
running around with weak batteries.
CHARGING
METHODS:
CONVERTERS: Here is the other place that the RV industry has
really let us down. Nearly all basic RV’s, whether they are trailers, fifth
wheels or motor homes are equipped with something called a converter or
“charger”. This mislabeled item should be called a battery maintainer, because it is designed to
be plugged into shore power in an RV park 24 hours a day, which is really what
the RV industry wants us to do. Converters are set to maintain the
batteries at the “float” voltage, about 13.5 volts, and supply a trickle charge
(2-3 amps, or 25-35 watts) to keep the batteries full, while not over charging
them and boiling them dry. Because of the length and size of the wiring in
most rigs, the converter supplies less than 13 volts to the battery.
Some newer converters will put out about 14 volts, but that is still too
low. You cannot
successfully charge batteries with a converter, because you never get the batteries up to the
required 14.4 volts. Don’t pay any attention to the amp rating of the
converter and don’t believe that it is a good charger just because it is labeled
three stage. It will put the rated amps out for a very short time after
you have run the batteries down or have just plugged in and it will taper the
amps off to a trickle at about 13 volts, long before the batteries are
full. Plus, if you have any solar power, the voltage it puts out will be
sensed by the converter and cause it to go into trickle charge mode even
sooner. I installed a new 60 amp Intellipower converter in a friend’s rig
& when we started the generator I measured only 4 amps output at 13.6 volts
right away. Does that sound like a battery charger to you? My solar
system actually puts more amps (3.5 amps) into my batteries on a cloudy day than
your average converter does, and I can’t keep my batteries charged when it is
cloudy, even with that trickle charge working all day. Therefore, you
can’t expect your converter to charge them, either. You are actually lucky
to ever get your batteries over 80% full with a converter that is plugged in for
several days. The single battery supplied on most small rigs holds about
90 amp hours. That is about 30
hours of charging from the converter, but at the same time you are still
running loads and reducing the power actually going to the batteries, so we are
talking days, not hours. The truth is that it takes even longer because
batteries are not 100% efficient, especially when they get closer to full.
In 2007 I repaired the solar system on a friend’s motor home that had been
plugged in for a full month at a park and then driven to our camp for a half
hour, with the engine alternator charging the batteries. He arrived with
his house batteries at 12.5 volts and the hydrometer showing them about 75%
charged. This is typical of rigs that are kept in RV parks &
occasionally taken out to boondock. They never have fully charged
batteries. Converters need to be plugged in 24 hours a day to work, not run for an
hour or two with a generator.
TOWING; or connecting a trailer to the tow vehicle and
idling the engine is very inefficient because the wires used are too small and
too long. The voltage drop is excessive and you are lucky to get more than
a few amps, once the tow vehicle’s battery is full and the voltage regulator
tapers the charge rate to the vehicle’s battery. Turning the tow vehicle
around and using big jumper cables connected directly from its battery to the
trailer’s battery will give you much more power. That will get you maybe
10 amps and up to 14.4 volts, which would take nine or ten hours to charge up that
single battery. It will work, but it still takes a long time.
PORTABLE GENERATORS: Those with a DC battery charging output
for direct connection to batteries work much better than plugging the rig in to
the generator and using the converter in the rig, or using a small automotive
type charger like I see many folks doing. This battery charging output
will give you about 8 amps at up to 14.6 volts, which does work, but will
take over 11 hours to charge up
that single battery. A converter is unable to fully charge a depleted
battery even when plugged in for days on end, and it only uses a tiny percentage
of a generator’s output, so running it on a generator is a waste of fuel. Plus,
the batteries will end up weakened due to not getting charged and will then not
hold a full charge. This is also true in motor homes with built-in
generators and converters. What you need is a battery “charger”. This can be a simple
automotive type, but it needs to be a big one, at least 25 amps, if you want it
to work by running it for a limited period of time each day on your
generator. A 25 amp charger that is run for two or three hours a day will
maintain a battery in the average small RV. Remember that it also tapers
off the amps as the batteries start to get full, so it doesn’t really put 25
amps per hour into them. A 25 amp charger will draw about 600 watts at 120 volts
AC, so you can run it on a tiny 1000 watt generator, but you have to be careful
and not run much else at the same time. You can run a 50 amp charger
(about 1200 watts) on a 2000 watt generator, but again, little else at the same
time. These numbers may not seem to add up, but you have a lot of
inefficiency when you are converting the AC output of a generator to DC in the
charger. One of the new “smart” chargers with a battery recondition
(equalize) button on them are what you need. Walmart now sells Vector
chargers under the Black & Decker brand name and they do work very well when
run on a generator. (So, you don’t have to have solar panels to charge
your batteries.)
INVERTER/CHARGERS: High end motor homes are now being
supplied with these rather expensive, but useful gizmos. The big ones can
quickly charge batteries when powered from a generator. The modern ones are
programmable for battery type and amp hours of storage and this is where I have
usually found problems. It seems that many of the RV manufacturers and
repair shops don’t know how to set them and if they are not set correctly, they
won’t work properly. The factory default voltage & amperage settings
on most of them are just as low as a converter and some will automatically
revert to that setting if you disconnect your batteries to clean the
terminals. It is very important to learn how to program your
inverter/charger correctly for the batteries in your rig, so you are getting
your money’s worth out of it. Remember, even these have to be run for at
least an hour after you get the batteries up to the proper voltage and since
none of them are set to 14.8
volts as Trojan recommends, an hour isn’t nearly long enough. If you set
them for a bit more amp hours than your batteries actually hold you can fool
them into charging for a bit longer. I recommend that you look at Magnum
if you want to buy a new one.
SOLAR POWER: Now, if you do decide to spend the money for a
solar system, you have found the person that can tell you how to make it
work. I am aiming this information at those of you like me, who have a
limited budget. However, even those of you with lots of money need to
become educated if you don’t want to be taken advantage of by the RV solar
salesmen, so keep reading. My wife and I really have been full time
boondocking for over seven years and we have never owned a generator. Don’t
listen to the folks that tell you the first thing you need in order to go
boondocking is a generator. Campers who don’t need to run the toaster
& microwave are better off buying one solar panel and a small inverter instead of a generator. We run
our TV, computer, battery chargers for phone, camera, tools, etc., plus coffee
maker, microwave, mattress heating pad, toaster, waffle iron, hair dryer, vacuum, power tools such
as skill saw, table and miter saws, router, sander, drills, heat shrink gun,
soldering iron, etc. You name it. We live a normal life, except that our
house is very small. My wife watches TV while she quilts with a sewing
machine, using an electric iron
to press the seams and I do remodeling & repairs, including building a big
deck in 2006, using power tools connected to our rig, at a remote cabin with no
electric service (where it rained for three days during construction). We
have only 345 watts of panels (that is less than three new 125 watt panels),
which we tip up to 50 degrees in the winter and six golf cart batteries giving
us 675 amp hours of storage, so we can get through a few cloudy days. One
person that I talked to about this (who owns a big rig with a huge TV) said “You
must never go anywhere that it rains.” A solid week of cloudy days like
you get in the northwest would put a crimp in our style, but we have no problem
living in Arizona in the winter, Utah spring & fall and summers in Wyoming
& Montana, where it does rain. Show me an RV with the roof covered
with solar panels and I’ll show you a solar system with more panels than they
need but does not work because it was added to and added to with no regard for
voltage drop. Adding solar panels to an under wired system is like putting
a big motor in a little car with a tiny drive train & skinny tires.
You can’t use the power.
Be very careful about who you ask for advice. (Don’t ask the guy with solar
panels and a generator running
behind his rig on a sunny day.) You also need to watch out for those who
brag about being charged up by 10:00 or 11:00 AM. They either have more
panels than needed or their systems are shutting off early because they are set
up wrong. When you see those guys with solar, wind generator AND the
gasoline one, you really need to start to wonder. Ask any “expert” if he
has ever actually done what I am doing and lived without being plugged in or
running a generator for more than a few days at a time. It seems to me
that anyone seriously in the business of selling solar equipment should be
living with it. Both his home and business should be off the
grid. If he is an RV’er, why is his rig parked behind his business
location & plugged into the grid? Electricity from the grid does cost
money, you know. Anyone who starts out by telling you what you cannot run instead of what you can run is the wrong person to listen
to, because really, with enough power, you can run anything. The solar
industry is letting us down by producing solar charge controllers that have
their charge voltage set too low (14.2-14.4 volts) and the installers are not
doing their job by verifying that the systems they install are wired and
adjusted correctly. (Most of them are clueless.) I have had several
arguments with these so called “experts” over these issues. Buyer beware! Close to 90% of
the solar systems with wet cell batteries that I have checked do not supply the
14.4 volts minimum needed at the battery terminals, either because they are set
too low (many are not adjustable) or there is voltage drop in the wiring between
the charge controller and the batteries. You have to realize that the
voltage shown on your charge controller is measured at its output terminals,
not at the batteries.
There is voltage drop in every
DC installation, even if the wire is very short, so all controllers need to be
adjusted upward in order to actually get the batteries full. The same
thing applies to the amps. I have seen systems with nearly two volts of
drop in their wiring and similar resistance loss, adding up to about a 25%
loss. 25% of a four panel system is one entire panel! You must locate the charge controller as
close to the batteries as you can or use BIG wire, so you actually get the volts
to the battery terminals. (#10 is not big.) Above the refrigerator
is absolutely the worst place for the charge controller, due to both wire length
and heat (the enemy of electronics), which should tell you something about many
of the solar installers, since this is still their favorite location.
Worse yet, some of the cheap controllers are set at 13.6 volts like the
converters, are not adjustable and their instructions say you can connect them
at the refrigerator supply wires, choking the power off and the money spent on
expensive solar panels is just thrown away. The attitude in much of the solar
industry seems to be that their factory settings are “close enough”, which is
absolutely not true.
Manufacturers of charge controllers also seem to worry way too much about over
charging, which is very difficult to do with the limited amps produced by most
RV solar systems. So, most of the systems people have had installed in
their rigs by the so called “professionals” are not really getting their
batteries full and they end up running their generators when they shouldn’t have
to. Many people with only one or two panels would actually improve their
system’s performance and not hurt their batteries if they removed their cheap,
nonadjustable charge controller and connected the panels directly to the
batteries. (2 or 3 amps will not hurt a 225 amp hour battery, no matter
how many volts you push it with.) It seems to me that if you are going to
spend all of that money on solar panels, you should do everything you can to get
that expensive power into your batteries. This means that money spent on
big wire and a better charge controller is a wise investment. The
difference in price between a cheap controller and one that will work is very
small, as is the difference between small and big wire. Don’t waste a
thousand dollars on solar panels and then throw half of it away by not
installing and adjusting it correctly.
Even with my background in electrical engineering and electrical equipment
sales, I was not knowledgeable about DC wiring and I’ve made all the
mistakes. My attitude all along has been that money would be more wisely
spent on solar panels than a generator and I would just not accept what I kept
being told by salesmen that were on the outside of the RV boondocking
world, looking in. I installed our first solar panel with the #10 wire
furnished in a kit and installed the controller above the refrigerator as
directed in the instructions. It did not work. I would take the
amps, hours and the rest of the information that was available, calculate,
figure & obsess and it never seemed to add up. I added a second panel
after three months of traveling, and then added tipping hardware. Our
batteries would still go deader & deader every day as we ran nothing more
than our lights & a tiny 9” TV. Then I listened to the wrong advice
& added two more batteries to a system that wasn’t charging the two that I
had. I finally figured out that voltage drop was the biggest problem, but
having no experience with DC power, it was a real challenge to figure out how to
fix it. We are now in our second rig, fourth charge controller and on our
eighth year of full time boondocking and are pretty much acting like electricity
falls from the sky in unlimited amounts. (Wait a minute…. Maybe it
does!) So, when I tell you it is possible to run on solar equipment, you
can believe me. We do
it. One more time: We have never owned a generator. Believe
it or not, most of the folks in the solar power industry, including the
manufacturers and the dealers do not know how to make solar power really
work. I’m not saying that none of them know, but it is my
experience that the honest ones who really know what they are doing are in a
very small minority and most of them are doing houses, not RV’s. Even
those folks will tell you that you need a generator and will not believe me when
I describe how well our system works. You see, most of them are just
selling the stuff and not relying on it like I do. There is a great big
difference.
One bad example of this was the technical guru of a company that manufactures
solar charge controllers and installs RV systems, who I had the occasion to talk
to because I was repairing an under wired inverter installation they had
done. I was thinking about replacing my controller with their new MPPT
unit and I was trying to decide if it was the right one for me. He could
not explain to me why their new controller was set a half of a volt lower than
the Trojan factory recommends and did not have the ability to equalize, while
claiming that they talked to Trojan all the time. He told me I would boil
my batteries dry by following Trojan’s 14.8 volt recommendation and then said to
use my generator & inverter/charger to equalize (after I had already told
him that I owned neither). He bragged that they tested their equipment on
the company owner’s own motor home with his roof “covered” with solar
panels. He said “of course he has a generator, everybody needs a
generator.” This was a very illuminating conversation for me. Here
was an “expert” on solar who evidently didn’t trust it enough to rely on it and
appeared to be ignoring what the biggest manufacturer of deep cycle batteries in
the country has to say. Looking back on this conversation a year or so
later, with more experience under my belt, and after installing one of their
controllers in a friend’s rig with AGM batteries (where it worked fine), it
occurred to me that the company in question had decided that we should all be
able to afford sealed batteries and were designing their controllers
specifically for them. However, their advertising, their installation
instructions and the numerous dealers selling for them have not been telling us this. Their
controllers work fine if not overloaded and if they are used as intended on AGM
batteries, which can be done if you go to their factory to get it installed, but
there are lots of them hooked up to wet cell batteries and that are not working
very well at all by dealers who have no clue what they are doing. I
replaced one that was badly misapplied by connecting too many panels to it and
then hooking it up to wet cells with small wires by one of those “expert”
dealers in Quartzsite. The controller was shutting off about a half a
panel’s worth of power because of being overloaded and what it did let through
was getting shut off when the batteries were about 80% charged because the
voltage was too low. I also can’t help but wonder just how many inverters
have been installed with cables smaller than Xantrex requires. I’ve seen a
lot of motor home installations done by the RV manufacturer that have too small
cables run too far from the batteries. It is more common than you would
believe. The only reason we are not seeing more problems is that most
folks do not load their inverters nearly to their capacity, like I do, so the
voltage drop issue is not apparent.
Following are some “Common Sense Guidelines” for designing a solar power
system that really works. One of my friends says common sense ain’t all
that common. Ain’t that the truth? I’m not going to get technical,
because you don’t need to. This is not an installation manual because
there are plenty of those already available. It is intended to be an
education guide. If you really want to obsess about amp hours, watts,
types of panel crystals or charger regiments you can go buy one of several
books, or go to a seminar that will confuse and probably misinform you.
Even worse, go on line & solicit the help of strangers who sit at their
computers, in rigs that are parked in RV parks, but claim to be experts on every
subject under the sun. Even before I figured out how to fix my system I
had walked out of two seminars at Escapades because the people running them were
so obviously lacking in knowledge. On the other hand, if you just want a
system that works and doesn’t cost too much, read on. As you read, keep
this in mind: I’m not trying to sell you anything. I just
want to help you get your money’s worth and prevent somebody else from taking
advantage.
HOW MUCH POWER?? Everybody is different. How’s that
for a generality? Examples:
We have RV friends that get by just fine with one 125 watt solar panel and
two batteries on a 34 foot class A motor home. They don’t watch a lot of
TV, but they do occasionally use a laptop computer. They were going to buy
a second panel, until I showed them how to reset their controller to get 14.8
volts to the batteries and now they have plenty of power. The dealer told
them they needed three panels, but did agree to put only one up initially and
use #8 wire, but then he left the controller at the factory default voltage
setting (14.4V on the controller/ 14.2V at the batteries).
We have other friends with a four slide-out fifth wheel, the built-in vacuum
system and 27 inch TV that get by nicely on only two 125 watt solar panels and
four batteries. The dealers told them they needed either three or four
panels. I told them to try two panels and wire it for three, and helped
them install & adjust it correctly. They used battery power with their
new inverter to run the built-in vacuum system to clean up the mess we made
& watched movies that night to see how things worked. Their generator
got loaded into the back of the truck the next day and wasn’t used again until
they got snowed on the following fall up in the great white north. These
people do not use the microwave or a coffee maker and they are successful with
250 watts.
We have other friends that you will recognize if you ever see them, because
of the eight big panels (800
watts) on the roof of their 40ft bus conversion, six L16 batteries, all of the
usual appliances, plus a 22 cubic foot over/under residential 120 volt
refrigerator. Their system seemed to work except for having to run the
generator any time it got cloudy for a few hours and then I convinced them to
let me do some rewiring, move their controller closer to the batteries and
replace it with a three stage C60. The generator doesn’t run now unless it
rains for more than three days in a row. They could be getting by with
only 500 or 600 watts, but with their over designed system they can now ignore
the rain. By the way, according to something I read in a solar dealer’s
catalog, they should need 500 watts just to run the refrigerator. This is
how I know that the information in that catalog is not to be trusted.
Then there are the folks who have six big solar panels tipped up on the roof,
one of the big expensive boost controllers and six batteries on their 40 foot
motor home that can’t get along without running the generator nearly every
day. They also have a 27 inch TV and a computer and a large phantom load,
but no electric frig & more than 600 watts of panels (don’t forget the
boosting controller). Their system was installed by a “professional”,
using too small of wire and even though the meters show that it charges, they
are losing at least 20% of the power their panels put out (a whole panel’s
worth) in wiring losses, even after spending hundreds of dollars on the boost
controller that would supposedly solve their inadequate wiring problem by
running 24 volts down from the roof. It does not work, because it does not provide
what they need and they won’t listen to me.
Then there are the folks we ran into only once, who had two panels (240
watts), four batteries and a noisy generator running on a sunny day. I
showed them with my meter how their system was wired inadequately and was not
getting their batteries above 75% or so, but they weren’t going to be
convinced. “The controller is blinking full and 14.4 volts” (It was 25 ft
away from the batteries, which were getting only 13.5 volts) and “by God, the
guy we bought it from knew what he was doing, we spent $5000 on it and you don’t
know what you’re talking about”. So, why is the generator running??
“We are using it to watch TV, so we don’t run the batteries down.”
They couldn’t watch TV all evening on their four “full” batteries without having
them go dead! Those four batteries should power their little TV for two
full 24 hour days and their panels could produce 3 or 4 times as much power as
the TV used, if it was only getting to the batteries. Sometimes you just
have to walk away, go home & start writing the RV Battery Charging Puzzle, which is
exactly what I did.
See, everybody is
different. You cannot tell by looking at somebody’s rig if their solar
equipment actually works and most folks don’t really know so be very careful
about asking strangers for advice. There are thousands of rigs out there
with systems that do not really work, owned by people that don’t know any better
and think their systems work, while at the same time being paranoid about
turning anything on, trying LED lights & burning candles. If you can’t
use your lights and appliances whenever you want to, your system does not work. Remember that your
appliances are part of your electrical system. You can spend money on more
efficient appliances like a smaller TV, instead of buying more solar panels and
end up with the same net result. This is not an acceptable compromise for
many folks, but by doing just this we are able to leave the TV on all day and
still be able to run things like the toaster that those other folks
cannot. Many people have gone to extreme measures with their lights to
save tiny bits of power, something that we have not done. We don’t like
fluorescent lights. I even replaced the fluorescent over the kitchen
counter with 12V halogen under cabinet lights that use twice as much
power. We just turn the lights off when we don’t need them. A
propane heater that keeps you from running the furnace motor is also a lot less
money than a solar panel.
That said, here is this stranger’s advice: If you want to just be able
to run your lights, water pump, charge the cell phone and run the occasional
small kitchen appliance, acting more like a camper than a full timer, you only
need one panel and one or two batteries. If you want to run the TV,
computer, the microwave to warm up soup or make popcorn and some kitchen
appliances you’ll need two panels and four batteries. Of course you need
more panels if you want to run any unusual loads like a freezer in the basement
or a CPAP machine to keep you breathing all night. It can be difficult to
figure out how much power any device needs because the labels generally show
higher watts than actual and then you can’t guess the duty cycle. There are
meters available (“Kill A Watt”) that can do this for you, but if you buy that
smart meter like I told you earlier even before you buy any solar panels, you
will have what you need. If you aren’t going to be able to climb up on the
roof and tip the panels during the winter, add 40% more panels and keep in mind
that the newer and fancier motor homes typically have as much as two amps of
phantom loads that you’ll never be able to shut off. You need to find
somebody like me with a DC clamp on ammeter and test your rig for phantom
loads. (Two amps over twenty four hours is 48 amp hours, and that is more
than a whole solar panel in the short winter days.) When I say panel, I
mean a modern one that puts out 100 to 130 watts. I don’t care what brand
or type, just check the warranty, calculate the dollars per watt and do some
comparison shopping. You will find that the bigger panels are a better
buy. Unless you stumble into a bargain on used panels it is short sighted to buy
smaller panels. Don’t buy more batteries than you need to get through a
couple of days unless you need to run big loads like a microwave oven. It
is not good practice to draw the 120 or more amps that takes out of only two
batteries. You do need more batteries for big loads but realize that every
battery you add has a built-in loss that must be overcome by your charger, so
more is not necessarily better. Adding batteries to a system that doesn’t
have enough charging power is like putting big truck tires on a compact
car. You end up with something that burns more fuel, but can’t carry more
cargo. Good luck if you try to calculate your amp hour needs based on what
you find in a book or at one of those seminars. The people that gave you
the info are trying to sell more panels. You won’t really know what you
need until after you have lived with whatever you install for a while, but you
can get by with fewer panels than you have been told elsewhere, if you install
them correctly. Regardless of how much power you use, you need nearly 3%
of your total battery storage amp hour capacity in charging amps in order to
successfully charge those batteries. With less, you can’t equalize.
For instance, six batteries with 675 amp hours capacity require 20 amps charging
(675 x .03 =20.25), which is three panels. Two panels do not produce
enough power to successfully charge six batteries. The number of panels
gets you the power needed per day plus some excess to make up for what you miss
during cloudy periods, while the battery capacity is what gets you through the
night, or in our case, through a few cloudy days. Remember however, that
panels do produce some power even on rainy days, so the batteries do not have to
be sized to power several 24 hour days of use like some dealers will tell
you. We have more panels than we need, so we can charge the excess of
batteries that we have, and so we don’t need to carry a generator. Having
a generator lets you get by with a smaller solar system. Wiring your
system for more panels than you buy will keep you from having to do things twice
and will make your system more efficient if you end up not needing to add
panels.
THE CHARGE CONTROLLER: FRIEND OR FOE? Charge
controllers are installed to limit the power sent to the batteries and keep them
from being damaged by overcharging. Therefore, one that is set too low
becomes the enemy of anyone who wants to actually charge their batteries until
full. The typical solar charge controller, which is a flush mounted two
stage or on /off device and rated 20 or 25 amps, is designed to maintenance
charge one or maybe two batteries. It tapers the charge amps off,
typically as soon as it reaches whatever its voltage set point is, which is
usually around 14.4V, instead of pushing amps in for a period of time as
required to get the batteries full. Go back & reread what I said under
batteries about the difference between 14.4 & 14.8V. That 20%
difference is like getting only $560 worth of power from a $700 panel, so a
controller that shuts off early is costing you money. The manufacturers of
these things have no idea of what we are trying to do with them out here in the
real world. They designed them to trickle charge batteries and keep them
from going dead, not to actually power a small house. So, our batteries
get “nearly” full, not really full. That “nearly” full battery will still
show 12.7 volts after the sun goes down, but it is not really full and also not
really healthy and will get weaker over time. Get a three stage charge
controller that will handle the power from more panels than you buy and that has
an equalize button on it. Equalizing is the source of much disagreement in
the RV world, and I know you don’t really need to do it if your charger is working
correctly. Trojan Batteries says to equalize when you need to, based on a
hydrometer test and I haven’t had to since I set my controller to 14.8 volts.
Also get a controller that is temperature compensated if you spend time where it
gets over 80 degrees for any length of time, or you should plan on remembering
to manually lower the voltage setting during the summer (something nobody does)
to keep from over charging and raising it in the winter because batteries need
more volts in cold temperatures. Setting it low all the time is what most
installers do, and that keeps your batteries from getting full and is very bad
for them. Three stage chargers are easier on your batteries, charge them
faster, fuller and help you use less water. Higher amp controllers let
more amps through when in the absorption charge mode, so they get the batteries
full faster. The charge control manufacturers are all very conservative in
their settings, so don’t worry about hurting the batteries by turning the
voltage up. And last, don’t load any controller to over 80% of its rating
(lower is better), no matter what the manufacturer says. You want it to
last for years, not just get through the warranty period. I bought a
3 stage Trace (now Xantrex) C60 for $209 in Oct., 2006 with the temperature
sensor, but no digital meters because I use a Link 10 to monitor the
batteries. This unit charges for an hour after it reaches the voltage set
point without tapering the amps. I replaced the Trace when the
temperature compensation quit working with a new Morningstar Tristar 45
($195.00) and I like it even better because it charges longer. These big
non-boosting controllers were designed to power home systems and they really do
work. My older (pre Xantrex) flush mounted RV controller was only four
years old, rated 30 amps and it was starting to act funny (failing). But
worse than that, it was designed by the manufacturer to start tapering the amps
long before it reached the set point voltage (a gentle finishing charge), so it
was shutting the power from my panels off before the batteries were full.
Why they think we need to taper what is already a trickle charge is beyond
me. I want all of the power my panels put out to go into the
batteries. I didn’t figure out that this was happening until I replaced
that controller and saw the big difference in the available power. Don’t
buy any of the little flush
mounted two stage controllers, including the “boost” models if you are serious
about using solar power. They all shut the power off before the
batteries get full.
MPPT BOOST CONTROLLERS (maximum power point tracking);
Yes, they do work, assuming that you run your batteries down low enough, which
you will hardly ever do if your system is set up right. My system runs in
the top 15% of its range 95% of the time. The magic boost kicks in when
the batteries are low and will accept more amps at a lower voltage. There
is little or no boost at higher voltages. Also, the manufacturers will
tell you that you can overload their controllers and they will limit the power and protect
themselves. If you look at the meter on one of these, it will show boost
even when it is limiting or tapering the amps, so just what is it doing;
boosting or shutting the power off? It can’t be doing both at the same
time! I can’t prove it, because I don’t have an independent test lab
in which to do testing, but I suspect that they play games with the numbers
shown on their meters, because they show quite a bit of boost even when the
batteries are at full voltage. I tested the input & output of one of
the best ones available with my Amprobe and when I multiplied the numbers to get
watts, I found that the controller was losing about 10% in its
electronics. It was definitely boosting the amps while lowering the volts,
but that unit was advertised to be more than 98% efficient, not 90% as I
measured. If you carefully read the reports on these controllers, you will
realize that the magazines never do comparison testing side by side with other
brands and independent metering. They simply report what the meter on the
charge controller shows as if it is gospel. The whole story is
suspect. My background was in the lighting business, where certified
independent test reports were the norm, so that is what I expect to see.
There doesn’t seem to be any such thing in the solar business. I’m
just not convinced that these controllers are worth two or three times as much
money. I know, the small two stage units don’t cost that much, but they
don’t work. I have replaced three of them with non-boosting three stage
units and the systems had more power afterwards, not less. Buy a three
stage boost unit if you can afford it, just don’t expect any ”25% or more” extra
power. Somewhere around 5 or 10 % is more like it and you are going to get
that much extra by running big wires. Last, don’t believe the latest
“trick” about fixing voltage drop problems in a system by running 24V down from
the roof in small wires and then transforming down to 12V in the
controller. All transformers (including electronic ones) have an
efficiency loss and the MPPT circuitry is not 100% efficient. You gain by
running 24V & then lose by running it thru a transformer. Last, the
boost comes from using excess volts put out by the solar panels and turning it
into amps. If you don’t install great big wires so that voltage is
actually getting to the controller, then you are wasting the extra money spent
on the MPPT controller. The big boost controllers cost a lot more than correctly sized wires to
install. The wire is a much better bargain. There is one company out
there that has been experimenting with custom lower voltage panels that are
designed to work specifically with their MPPT controller. I have seen the
same theory offered on-line in residential systems. The theory is sound
and should work, if wired
correctly. If you are willing to go to their location and have the budget
this can work and probably uses less roof space. However, you need to do
some serious comparison shopping before you decide if it is worth the price.
WIRING: Resistance or impedance is the enemy. You have
to overcome it and get the power to the batteries, not just to the output
terminals on your charge controller. The system in my rig is efficient
because I wired it with six gauge wire, for a total distance of only 12 ft from
panels to controller. I ran #4 from the controller to the batteries.
I spent about $30 for this wire and gained about $120 worth of added power when
looking at what 6% of what my panels cost, which is about what I gained when
going from 25ft of poorly routed #8 wire to 12ft of #6 wire. Big wire is
even more cost efficient when you are looking at the difference in cost for a
new installation. If your controller is located very close to the
batteries like it needs to be, it will regulate the voltage to the batteries so
they get what they need. You can run smaller wires from the panels to the
controller than you run from there to the batteries, but make sure you can get
about 16 volts minimum to the controller by looking at a voltage drop table. Big
wire is cheap compared to the cost of panels, so err on the big side. You
can either run big wire or install multiple smaller runs and split the panels up
into several feeds. DO NOT tie the wires together at both ends. One
wire will always have less resistance & carry more of the load. Find a
voltage drop chart and limit your loss from the roof to the batteries to
3%. This way you can ignore the drop in the wires on the roof. You will
find that voltage drop is directly proportional to the number of amps (higher
amps equals more voltage drop), which is why you should wire for the number of
panels you might need and not use the minimum size for the panels you initially
buy. A perfect example of my complaints about solar dealers can be found
in the Backwoods Solar catalog, where their wiring chart is based on 5% drop
(not 3%), and in looking at the numbers, I’m convinced it is bit
optimistic. Backwoods is a good company (I send them a lot of business),
but remember they are selling panels and want you to buy more. I know, 5%
isn’t a lot and most dealers think that 10% drop is fine, but think about this
for a second. They get to sell you more panels to make up the
difference! Let’s see, you can spend $100 more on wire or $650 for another
panel and get the same results. Duh! (I can say these things because
I’m not charging you anything.) Use BIG wire, at least #8 for two panels
and, and #6 for three panels and that is only for runs under 20 ft. I have
installed a lot of #4 cable and wish I had it in my own rig.
A word on the stranded wire debate: Yes, you should use stranded wire
because it is better for DC power. However, the difference between
building wire and finely stranded automotive or welding cable is teeny, tiny
electrically, so don’t obsess about it. The finely stranded stuff is
easier to work with, but the main thing to worry about is a UV rated shield on
the roof, protection against damage when routing through the rig and the
price. Buy what you can find at the right price and what you can deal with
mechanically. There is nothing wrong with running big, stiff wires and
then splicing short, flexible leads on the ends to make it possible to connect
to terminals. The big wire is there to limit voltage drop, not to
carry amps. You are not going to load it enough for the splices to get hot
and fail.
INVERTERS: I use two inverters in the rig and carry a third
in the truck for portable power for the lap top. This may seem like
overkill, but I have my reasons.
The first is a Morningstar Sure Sine 300 watt pure sine wave unit that is
located near the batteries and connected to them with 4 gauge wire and a 60 amp
fuse. From there I ran a 12 gauge building wire to the entertainment
center where it powers a custom built power center with individually switched
receptacles for the various appliances such as TV, stereo & sewing
machine. With this I can individually turn the TV & other devices off
& not have them drawing power to keep warm, (the TV draws only .1 amp, so we
leave it on). Another cord runs to the mattress heating pad & the air
pump for the Select Comfort bed. This may seem like a lot of trouble and
expense, when I could just turn my big inverter on to run anything, but I figure
that I am getting as much extra power from this as I would from $350 worth of
solar panels and wiring. Those big inverters constantly draw over two
amps. Power saved is much
cheaper than power generated. I resisted buying a sine wave inverter for
years and finally bought one in 2008 after having two cheap inverters fail and
realized that I was risking $500 worth of TV & stereo on $40 inverter
power. However, we did go for eight years, powering everything from
modified wave inverters.
The second is a large modified wave power inverter (with no charger) that is
also located close to the batteries and connected through a 400 amp time delay
fuse with #4/0 cables. It supplies the 120 volt panel in the rig through a
manual transfer switch and there
is a remote control switch in the Kitchen, so we can turn it on only when needed
because it has an idle current draw of over two amps. (The breakers that
feed the air conditioner and water heater are switched off and the fridge is
switched to gas.) Since we never plug in, we never have to remember to
flip the transfer switch. Manual switches are reliable. This
inverter is a 2200 watt unit that has a surge capability of 4600 watts. It
will successfully run my 1 ½ HP air compressor, table saw and anything else I
want. I used it to power the seamless gutter installer’s machine at a
cabin site in Montana. You should have seen the look on that guy’s face
when I showed him where to plug in! I don’t own a battery charger, because
I have no generator to run one with, and inverter chargers are expensive.
Well, actually I did replace the converter with a tiny ten amp battery charger
just in case, but it has only been plugged in when forced to park under trees at
a friend’s house or when covered with snow, which we don’t count as being hooked
up.
If you can afford it, and already have a generator to power it, an inverter
charger is the way to go. They have a built-in transfer switch, which
simplifies installation, and a big charger that is programmable so it can be set
up for whatever batteries you have, though it would be nice if they were set to
a higher voltage. You must have a transfer switch because you will burn an
inverter up by connecting its output to outside power fed back through the
electrical panel. You would think that everybody in the RV business would
know this, but I keep finding failed inverters installed without transfer
switches by RV dealers and the owners of the rigs have no clue what has
happened. I even found one where the installer had not connected to the
built-in transfer switch in the inverter charger! The transfer switch can
be a simple cord & plug arrangement instead of a $100 automatic switch, just
make sure it is fool proof. The biggest challenge with an inverter
installation is figuring out how to hook it up to the loads; the whole panel,
one phase of the panel in a 50 amp rig, add a separate panel or connect to one
circuit only. There is just too much variety to make it simple.
Whenever you read anything that tells you to always do it in any one way, you
know that the author doesn’t have much experience. It is not that
easy.
A word about Sine wave inverters: Unless you need to power something
that must have a pure sine wave,
(and don’t believe everything you hear), you don’t have to spend the extra
money. I know, a pure sine wave inverter does a better job of powering a
microwave, toaster or hair dryer, but how much money do you have to throw
away? The money we saved is more important to us than the convenience of
running the toaster for a few seconds less. Big sine wave inverters are
expensive and they have high idle losses, (up to five amps) which can be enough
to require you to buy another $700 panel. Get that appliance to somebody
with a decent modified wave inverter, plug it in and find out for yourself if it
works. Just don’t buy the cheapest inverter you can find. My Vector
starts my 1 ½ hp tools like they are plugged into the grid. My last
inverter was a Heart 1000 and it worked just fine, except that it was too small
to run my power tools. I have been recharging my Dewalt tool batteries for
six years on modified sine wave inverters and haven’t burned one up yet.
So much for that “fact”. My wife bought a new computerized sewing machine
in 2006 and it is working just perfectly, thank you. We have friends that
run big juicers and food processors on their modified wave inverters. The
only appliances I have heard of that absolutely need sine wave power are
residential refrigerators, washing machines, some air purifiers and Craftsman
brand battery chargers. Both the inverter and appliance manufacturers are
controlled by their lawyers; they are overly cautious.
Warning: Properly adjusted solar systems with temperature compensation
will regularly exceed the 15 volts many small inverters use as a high voltage
shut down. Xantrex has changed their X-Power line so that their inverters,
manufactured by a company that also makes solar charge controllers, will not
work on properly operating solar systems. Go Power & Cobra are others
with this problem. They don’t realize that there is another market besides
the truckers. Many of the cheap inverters have this problem, as well as
noisy fans that run continuously. The small Vector units work, but have
noisy fans. The Morningstar Sure Sine 300 has no fan, a 600 watt surge
rating and very low idle current. Of course; it costs nearly $300. I
finally bought one anyway and have not regretted it.
BATTERIES: This one place where I believe that you truly do
get what you pay for.
I bought Trojan T105’s back in 2001 because I talked to many people that had
them and found no dissatisfied customers. The only complaints I have ever
heard about Trojan were concerning price or came from a dealer selling something
else (sour grapes). Mine are now over eight years old and just recently
started getting a bit weak. On the other hand, I only got one year out of
a set of deep cycle 12 volt marine batteries that never tested the same as each
other. You can’t always compare amp hour ratings because the different
manufacturers like to play games with their numbers and use differing rates of
draw. I plan to buy four new larger Trojan or Crown batteries next summer,
instead of six T105’s, which will save some weight & have less to go
wrong. Recently (spring 2007) Interstate had some problems and I still
keep running into folks with bad Interstate batteries. I think they had a
bad production run. One dealer I talked to about the problem tried to tell
me that a hydrometer is not an accurate way to tell if an Interstate battery is
fully charged and the new Interstates run at a lower voltage. Huh?
Interstate has published nothing that he could produce to confirm his
statements, so I think we were getting the brush off. The replacement
Interstates (a different model than originally purchased) tested just fine with
a hydrometer and charged right up the first day of full sun, and I believe the
technical data I got from Trojan, who say that a hydrometer is the best way to
tell. Buy whatever you want, but get 6 volt batteries and wire them in
series for 12 volts. The differences between batteries average out this
way and they match up better. Should you buy AGM or whatever new battery
comes along? Do your own research, ask everybody you run into about their
experience, weigh that advice with common sense and make your decision. My
decision was based on value and history and it may very well be different in the
future, since no battery lasts forever. Just be very careful about researching
the charging requirements of whatever you decide on. Get this information
from the battery manufacturer, not from the manufacturer of your charge
controller. This is critical if you want the batteries to get fully
charged and to last. A side note about not owning a big charger: My
batteries stay clean and hardly gas at all; you could eat off of them. Big
chargers are wonderful in some ways and terrible in others.
Now, I will tell you why I am not a fan of the new technology batteries like
gel cell & AGM: Your charge system has to be set at a lower voltage
for them, so more of the power your solar panels could produce is not available
for use. (Lower volts equals fewer watts.) This can be offset of if
you spend the extra money to buy a three stage MPPT controller. Therefore,
you must spend more on the batteries, more on the charge controller, plus the
big wires to get that voltage to the controller and you end up with batteries
that store less power in the same amount of space. (They are rated at
fewer amp hours.) All this so you don’t have to add water and can’t check
the electrolyte to monitor their condition. Suit yourself, but this really
doesn’t sound like a good bargain to me.
Regarding battery cables: Make all of your interconnecting cables up
the same length & gauge. (Heavy enough for the inverter load.)
Connect diagonally across your bank of batteries so that you have the same total
length of wire between each battery and the connections to hot &
ground. If you have a chain of six batteries, two will be closer to hot
and two will be closer to ground, but the total wire distance will be the same
for each of them, so they will get an equal charge and will also be drawn down
together. This is critical because we are really only trickle charging
with solar power and we have to make sure the batteries all get the same
charge. Any tiny difference will get worse over time and can eventually
ruin your expensive batteries. Don’t listen to the guy that says you have
to buy all that extra cable to make every cable the same length and connect to
common hots and grounds so all the batteries are connected exactly the
same. It is a waste of money and adds more connections that all have a
potential for failure.
A word on cable connections: Many of the so called “professionals” are
doing a very poor job of crimping. You test crimps by trying to pull them
apart, so do just that in front of the guy you bought them from. I once
had three of twelve crimps fail that some “professional” had done and he wanted
to know what I had done to them. I now carry my own big crimper, and I do
all double crimps. (This is a UL requirement in the real electrical
world.) If a hot wire comes loose while you are going down the road and
falls against the frame, it will turn into a welder. You don’t want to become
a burning hulk at the side of the road. Make sure those connections are
good and solid.
INSTALLATION & LOCATION OF EQUIPMENT: Locate the charge
controller as close to the batteries as you can. It puts out the power
that the batteries need and if you run any distance to them, they won’t receive
that power. While you can compensate for voltage drop in wires that are
too long by turning the controller set point up, this is bad practice because
the voltage at the batteries will rise as the amps drop off late in the
day. You can easily end up with an over voltage condition, causing all
kinds of problems. So, you have to set it too low to really get the
batteries full while the amps are being generated in the middle of the
day. Try to find a short route to get from the roof straight to the
batteries and put the controller between, at the battery end of the run.
You will learn over time that the controller does not need to be constantly
watched, so worry more about how well it works than how easy it is to see.
Mine is buried in the basement and I never look at it. While the
refrigerator vent is an attractive route for wires, it is hot and is rarely in
the right place. Run the wires up inside of a wall, cabinet or
closet. Then go ahead and drill a hole in the roof and plug it by bolting
a weatherproof plastic box down over it that is sealed to the roof with
caulk. This will never leak. Buy one big enough for all of the big
wiring connections it will contain (big mechanical splices, or wire nuts for
small systems), and then seal the holes out onto the roof with UV resistant
caulk like Dicor or ProSeal. You can run multiple 10 gauge standard solar
system cables on the roof (one to each panel) and not worry about voltage drop,
then run big, non sheathed cables down to the controller.
Locate the panels on the roof so that they are NEVER shaded at all by the
vents, air conditioner, etc. There are a few panels on the market that
will lose just some power if partially shaded, but most go completely
dead if you shade just one cell (like with a TV antenna). A shadow 4” x 2”
on the bottom of one cell, caused by a vent cover proved to cause 25% loss of
the panel’s output. A 3” high x 30” long shadow on the bottom of a panel
from an air conditioner measured 50% loss. These numbers are real! I
have even measured a .2 amp loss caused by a skinny CB antenna!
A $700 panel that is dead because a shadow falls on it is not much of a
bargain. The “professionals” that install systems have done a lot of poor
installations by ignoring this problem. They must know better, so selling
more panels has to be their agenda. I have been amazed and appalled
several times when evaluating systems at what I found on the roof. You
don’t really want to have a lot of extra holes in your roof (like on mine) due
to poor planning, so try to get it right. If you tip them, make sure you
get hardware that gets them up higher than 45 degrees. I’ve
seen a lot of standard mounting bars holding panels at 30 degrees or less (about
10% less power). Last, you need to face the panels south. I have seen several rigs
parked with their panels tilted up & facing east! I’m afraid to ask
what their “really good” reason for this might be! Their systems are
completely shut off in the afternoon when the sun is shining on the bottoms of
their panels! I have learned to not ask questions of those that are
obviously challenged, just like those guys with 6 panels & a generator
running on a sunny day. I have tired of trying to reason with the
unreasonable.
FUSING: This just flabbergasts me, but I run into unfused
wiring all the time in RV’s, some of it installed by the original RV
manufacturer, and some installed by “professional” RV technicians. I say
“fuse” on purpose. I don’t like the automotive type automatic circuit
breakers. First; you can’t turn them off like you can pull a fuse for
disconnecting; and second, breakers are mechanical devices that are prone to
failure. I have also found a few that were drawing a phantom load.
Don’t use the in-line fuses with springs behind them for a heavy, constant load
like solar charging. They tend to get warm and eventually melt down.
This is true even for the larger ones in a clear plastic case that the solar
dealers sell. I use the big stab-in automotive type or the 250V cartridge
type commercial fuses & holders. One of the folks I sent this to
came up with a brilliant suggestion for fusing the solar leads; a two pole fused
air conditioner electrical box with a pull-out disconnect. They are
available 30 & 60 amp and have #4 lugs for the big wires we need to
use. Connect the input from the panels to the controller on one side &
the output from the controller to the batteries on the other.
Disconnecting the entire solar system is then one simple motion. They are
dependable and cheap. The bottom line is that every single positive wire
needs to be fused within inches of the battery so that it will be protected
should it ever rub against something metal and cause a short, starting a fire,
or worse. Batteries have been known to explode if shorted to ground.
SUMMARY: I hope to improve the RV world one rig at a
time. Please tell your friends and hand copies of this out like confetti,
just don’t give it to the “professionals” that will tend to get defensive and
disagree with half of what I say. One of them has even labeled me “Overkill”
Bob. I have no problem with that, because he has it backward. If you
let him, he will sell you more panels than you need and a $600 boost controller
that definitely deserves the overkill moniker, plus a true sine wave inverter,
and try to convince you with a very arrogant attitude that you are stupid if you
don’t buy both. THAT is the very definition of overkill.
There is a better way and you do not have to buy a generator first to
go boondocking.
Generators??…………. We don’t need no stinking generators.
NEW INFO & PHOTOS ADDED
JULY 26, 2009:
Now for some photos of the problems I have found. It seems that photos
are needed to drive the point home about the things I write about. These
are just a few examples. I have found similar issues on systems installed
by the majority of the RV solar dealers, even those that have a good
reputation. Some of them have gotten better over time, but I have found
problems in installations done by most of them. As I have said over &
over, most people with solar power don’t know if it is working properly.
These photos are of systems owned by people who sought me out because they had
talked to others who have solar power that now works, thanks to my help. I
only recently started taking photos because I never intended to go to this much
trouble. Early on I optimistically believed the problems were rare, but
over time I found that problems like these are way too common. Some of the
photos that I didn’t take would have been a lot worse than these. I have
found everything from stupid mistakes to extremely dangerous wiring problems
that would scare you to death. I have nothing but my memory to relate most
of them.
The numbers I give for amps & percentage loss are based on measurements
taken with a very expensive Amprobe clamp-on meter. Watching the output
shown on the meter while moving a panel or causing mall shadows is something
that really opens people’s eyes. Nobody wants to believe what I say about
small shadows causing big losses, but it is true.
CASE STUDY #1:
This is a 40 foot motor home with six solar panels and a generator that runs
nearly every day. They have a small freezer in their utility trailer and
they own a 38 inch TV. While most folks think this is just too much to
expect of solar power, you need to think about this. This system is 720
watts, enough power to run a small home, if the energy produced by those panels
could only get into the batteries. What I found on the roof was
unbelievable.
Minus 2.5 amps
You would never believe that unless you saw what happened to the meter
readout when we unbolted the panel and moved it about two inches.
Two shadows add up to minus 6.4 amps.
6.4 amps!! This is 90 % of the output of a full panel.
What I found in the battery compartment was even worse that what was on the
roof.
Poor location for a charge controller.
The 40 amp controller in this photo was installed in the battery compartment
by the best dealer in Quartzsite and they told the owner of this motor home that
they would guaranty it forever. Not only is this bad because of the
potential explosive hazard due to Hydrogen gas and the corrosion problems due to
sulfuric acid, (the stainless steel cover screws were rusty), it was connected
to a potential of 42 amps from the panels with #8 wire, dropping the voltage so
low that the batteries were never charged. The batteries were shot due to
constantly being undercharged.
I refused to work on it unless I could replace the controller with a properly
rated Morningstar Tristar with a temperature sensor and locate it in the next
compartment over with the inverter. After rewiring with #4 cables, fixing
the multiple shading problems on the roof, and doing some reprogramming and
education concerning his Link meter, this guy now successfully runs everything
he wants, including a the 38”TV and the freezer, without running the
generator. The generator is only needed after a couple of cloudy days.
CASE STUDY #2:
A 40 foot fifth wheel with six panels, three controllers and owners who never
use electricity because their system does not work and they hate to run their
generator. The people that own this rig had spent over $6000 and were
afraid to turn anything on. This is a perfect example of what I say about
the dealers setting you up for failure. The problems were unbelievable,
from six improperly wired batteries scattered in three different compartments to
long runs of #10 wires from three junk charge controllers mounted up near the
ceiling. Only two of the six panels did not have shadowing problems.
These folks had bought solar, added to it twice and it still didn’t work.
They bought from one of those “professional” dealers in Quartzsite who has
been in the solar business for years and turns out non-working systems
daily. The cheap controllers he supplied are not suitable for paralleling
and it says that right in the instructions that come with them. I guess
“Professionals” don’t need to read the instructions. Then, this dealer has
been installing 25 ft runs of #10 wire for years and seems to have absolutely no
clue about the voltage drop this causes. After having several
conversations with this guy, I suspect that he does know, but doesn’t
care. People with under wired systems buy lots of expensive solar panels
and that is where the profit is in the solar business.
Minus 50%, worse if tilted.
I should have taken a close-up of the terminal strip next to the air
conditioner. It was the kind of thing intended for use in a protected, dry
environment, but it was installed exposed on the roof. The connections
were rusty and the wires were exposed to the sun. We moved the panel a
couple of inches over & up to get out of the shadow and added tilts to both
panels in the photo, resulting in more than doubling the amp hours.
Minus 2.9 amps.
Adding legs to the mounts & raising the panel a couple of inches solved
the problem.
Dead, zero, nada.
Same rig, but Teton is to blame this time. They had unknowingly copied
the solar dealer’s mistakes. Really though, were those accidental or on
purpose? That guy has been in the solar business long enough to know
better. I often wonder if the system in his own bus is any better.
This panel was shut off by the dish in the morning and the air conditioner in
the afternoon. It worked for just a couple of hours a day. There was
another panel just ahead of the air conditioner with morning shade
problems. By moving these two panels and adding tilting mounts we probably
tripled the amp hours.
This system now has a Morningstar Tristar controller with temperature
regulation, #4 cables down from the roof and a Trimetric 2020 battery
monitor. Their rig is just about the most beautiful full timing mobile
home you can find, with everything from a 42” TV with satellite & Tevo,
broadband internet dish with a wide screen lap-top to a built in vacuum system
and they may never have to plug it in again. I hadn’t heard from them in
months, so finally I phoned to ask how things were going. I was told that
it was working just like I told them it would. They hadn’t called because
they didn’t need to. They were now running everything and the generator
hadn’t been run in months. They would have been successful with only four
panels, if only they had been installed correctly. Now, with six panels
they can run whatever they want on cloudy days.
CASE STUDY #3:
A nearly new motor home with recently installed solar that did not
work. These folks are more of the “minimalist” type, who never wanted to
be able to use the microwave or a toaster. They were hoping that two
panels would run their rig and then let them use their TV for a couple of hours
and power the lap-top for checking e-mail. They didn’t have enough power
to do that and were ready to go back to the dealer with the money back guaranty
to buy another panel.
Suprize! MInus 2.5 amps.
Close-up.
Surprise! That tiny shadow from the vent cover is cutting the power
produced by 2.5 amps, 30% of the possible output from that panel. Before
you say that all the guy has to do is lower the vent cover a little, think about
the shadow that would be there if a Max Air cover were installed. Don’t
you think that somebody who has been installing RV solar for as long as that
dealer should know better? No warning was given. I doubt that the
installer had a clue about what he had done.
I have no photos of the rest of the problems in this rig, so read my “More
System Problems 2009” where the voltage drop issue is explained. Thanks to
a new Morningstar Tristar 45 amp controller with temperature compensation that I
mounted two feet from the batteries (after extending the #8 negative wire to
there) and a Trimetric 2020 battery monitor, I talked these folks out of buying
another solar panel. (It took a lot of talking; they were convinced that
another panel would solve their lack of power, while it was actually caused by
poor installation.) The last time I talked to them it was looking like
they were getting about 105 amp hours per day into their batteries on an April
day with the panels flat, about 10% more than they could get before with the
expensive little “boost” controller that I had removed, even if it had been
rewired correctly. I got to this conclusion by monitoring a nearly
identical installation in another rig that kept the boost controller, but moved
it close to the batteries. Three stage charge controllers that cost less
than $200 do work a lot better.
These folks are now successfully everything they wanted to with only two
panels. They may have to occasionally run their generator, but since it is
one of the big diesels, connected thru a very good Magnum inverter/charger and
both are already paid for, what the heck. Spending the money for another
panel that would require them to rewire the whole system because of increased
voltage drop does not make
sense.
ONE LAST TIME: I AM NOT SELLING SOLAR EQUIPMENT!
