Solar Panel question

With a trailer I would want 4 6-volt batteries and for each 100 AH at 12 volts I would want 75 Watts of solar panel installed.

Useful to think more in terms of amps of output than Watts. A panel that provides 6 amps of current will provide 24 amps of charging easily regardless of the weather. A 100 AH battery can be discharged 50% safely and that 50 AH of current can be replaced in 8 hours with the 6 amps of panel output.

A very good investment is a Trimetric charge metering device. Cost is under $200 and it will tell you exactly how much charge is available in your batteries and how much charge is going in or out at any given point in time.

If you plan to camp in areas where there is not going to be AC power, i.e. boondocking, the advantages of a trailer are more tank capacity for fresh water, grey water, and black water, and more roof space for solar panels. If you plan to boondock I would put in as much battery capacity as will fit and get someone other than the dealer to install the necessary number of solar panels to keep the batteries charged.

The great thing about solar is that once the system is in place you can forget about it as it runs itself and requires no maintenance.

100 Watts is a very nice size and you have your generator for charging when necessary. The panel will really help the life of your batteries by keeping a more stable charge and generally will not allow a full run down if you don't leave a heavy load on such as the fan for the heater.

You can really lower your energy use if you change your light bulbs to LED's.

I have had solar on three RV's. Self installed since I am an Electronic Tech.

OMG! I think we have seen the light, literally. Please keep the good posts coming on this subject and THANK YOU. I think you may be saving us a big headache and some expenses. Believe in doing it right the first time!

We have a single 100w panel with a cheap Morningstar controller (PWM) on our remote camper (34ft bunkhouse semi permanent) and it's enough for furnace, detectors, fridge controller (using propane, of course), and old lights that haven't yet been upgraded yet. But it's bright Western sky, and we have two 6v gold cart batteries. Whatever we use on a cold night with the furnace is made up mid day. We used to run 400w inverters from the 12v plugs for tv, which worked if the tv was not too big. Now, I have a separate workshop solar power center to send only 120v to the trailer for TV and charging things. We disconnected the DC converter since the 100w panel still does the job!

But, get the thickest wires run from the drop down point on the roof, and from your controller, so you can easily add more. You're going to love being able to use a toaster or hair dryer without cranking a generator, just need some good batteries, cable, and inverter. Any wattage panel will eventually catch up with your use, but you'll have to wait for the 100w a lot once you go with a decent sized inverter. Cause now you can run power tools, compressors, vacuums.......

We love having solar, even if it's to just power the fantastic fan while it's parked at a big shopping area.

I made at least four mistakes when I had solar panels installed on our 32'DP:

1) I thought I knew enough about solar power.

2) I thought the techs and solar "professionals" knew what they were doing.

3) Had a professional (RV Tech) install 2 80 watt panels, with wiring capable of carrying at least twice that. Wire not really adequate for upgrading as a I later found out. See item 2.

4) Had a professional (Solar installer) add 2 130 watt panels and new controller. See item 2 again.

Now I need to seriously upgrade the wiring AND move the controller roughly 25 FEET closer to the batteries!!!!! :S



Listen carefully to the advice of the many experienced and knowledgeable people on this board. With their suggestions I was able to improve the system significantly until I can get home and rewire.

I would also suggest that if you don't go bigger at the start, be prepared to do so later and make provision at the start.

100 watts is enough to charge the batteries if you use them fairly lightly in the summer.

We lived without hookups on a 130 watt solar panel for a full year in our 27' TT, and in the summertime, using just one laptop between us and watching just a little TV, we were fine. In the winter it wasn't enough, so we upgraded.

If your husband is handy, installing solar panels is not such a huge thing. We installed panels on two different trailers and on a sailboat -- in each case we did the installation without shore power and without a generator either.

We've written a lot about our solar panel installations on our website, including an easy-to-digest solar power tutorial that explains the various components used in a solar installation:

RV Solar Panel installation and Solar Power Tutorial

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Hi,

You would be better served by 300 watts. It would be far cheaper to do an after market installation, and you will know it has been done right.

Another option would be to set the system up to where you could add another 100w panel in the future should you decide to do so. The prices of panels has come way down over the last year. If you explain to the factory that you might want to add on in the future and to install an appropriate controller, they might be able to accommodate you. Once the main wiring is in (the hard work) adding a panel should not be too difficult.

You need to do an energy audit based on your anticipated usage of AC and DC loads. Then you can size a system to accommodate your consumption.
http://www.jackdanmayer.com/rv_electrical_and_solar.htm
http://www.amsolar.com/home/amr/cpage_9/rv_solar_education.html
http://www.quartzfest.org/php/main.php?RV_Solar_Battery_bank_and_Solar_systems_by_N8GS
Install on the road is entirely possible, competent system design comes first.