Tony, here is a reply I sent to someone else on solar power. We bought a system in 2006 from a vendor in the high desert near Southern California, Solartron Technologies, because I could go see the product and knew that had it in stock and wouldn't sit on my money while they waited for all the parts to come in. I would recommend them if you are within an easy drive of Victorville. Also, there is more discussion about quality vendors now and I know Lewster in this forum now represents and installs AM solar equipment so I believe they are a good vendor also.
I did all the planning for the layout and my wife and I did the install, however I am an engineer by education and vocation and as an amateur radio operator, home repairman and mechanic, I work on every thing we own that I can dissemble and diagnosis; Airstream, car, house, motorcycle, radio equipment, etc. It is not hard, you just need a modest understanding on electrical or be willing to read some of the good books on the subject and be unafraid to cut, drill and work on the Airstream.
Our system uses two 135 watt panels (Airstreams factory system for large trailers is only 100 watts) and a MPPT (maximum power point tracking) charge controller that provides more charge output to the batteries than the older PWM (pulse width modulation) charge controllers. We have two Group 24 Gel Batteries Group 24 was the original size for our trailer and fit without modifying the battery box or installing the batteries inside).
We find that the system works very well in the southwest where we have lots of sunshine. The Airstream has not been plugged in to commercial power since we installed the system in July of 2006 except to get the refrigerator cold before a trip or when we stop overnight in RV parks when traveling across the country. The batteries fully charge up in 3 to 4 hours even after running the furnace with night time temperatures near or below freezing if we have good sun in the morning. I believe we might have to get our generator out if we were boon docking in one place and had three or more days with heavy cloud cover and night time temperatures at or below 32 degrees. We occasionally use a 12 volt
lunch box cooker bought at a truck stop to cook, chili and hot dogs or hot sausage and even a pot roast for four people with potatoes, onions and carrots but we need good sun since the cooker requires 10 amps alone and I have seen charge currents of 14 amps when we were cooking and had other loads on in the trailer. We do use an inverter to run the factory Flat screen TV and also to charge things like our computer and small vacuum cleaner.
It does charge on cloudy days but might not be enough if you camp in lots of forest areas with shaded spots. I do plan to add more battery capacity in the future, probably modify the battery box to hold two larger six volt Lifeline AGM batteries wired in series.
If you have more questions or want to install the system yourself you might give me a call (951.780.5199 some days, weekends and evenings or 951.453.1944 cell) so I can give you some pointers and let you know what to watch out for. Two are you might need to use a little bit smaller panels to fit them on the roof of a trailer that is narrower and shorter and you need to make sure that you limit how deep you drill bit penetrates the skin in a couple of places so you don't hit any wiring in the roof of the Airstream.
You can view my article that was in the April 2007 Sierra Nevada Unit newsletter http://sierranevadaairstreams.org/sn...snu-nwsltr.pdf
and a more verbose version with pictures on the SNU web site: