Most of the 'tax credit' systems are installed permanently in a house, and are 'grid intertied'. Because I plan on driving my RV, and not leaving it connected to the house all the time, I don't think it would qualify for grid intertied system.
Solar systems are not nearly as expensive as they used to be, and intalling it yourself is not much harder than installing a headlight on a car.
What I did was install the brackets on the roof, then bolt the panels to that bracket, and run wiring down the vent for the refrigerator. That goes to the controller, and on to the battery.
The brackets can be made from 6" long 2" angle aluminum, and drill 3 holes 3/16" for #10 screws into the roof, and 5/16" hole for a 1/4-20 bolt into the solar panel frame.
#10 grey romex from Home Depot will provide UV resistant wiring. The controller for a 12 volt 'nominal' panel is only about $25- $35 for a 20 amp model at aliexpress.com 12 volt nominal will have a 19 to 22 volt 'open circuit' rating, and will charge a 12 volt battery effectively.
SunElec.com sells solar panels with aluminum frames in the $1 - $2 per rated watt price range. I would recommend something in the 100 - 150 watt size, as more than 150 watts is to large to fit on most RV roofs.
Your total system cost will be between $200 and $800. Why worry about a tax deduction? Taking a long trip will cost more in gasoline! And if you start dry camping more often, you can save $10 a night in camping fees, paying for the system in about 30 nights of dry camping. . . I paid $3000 for my system (back in 1994 a 90 watt solar system at $750 was a great deal and no tax incentives at that time). By 2004 I had dry camped more than 300 nights, and completely paid for the system. Between 2006 and 2007, I full timed and paid for it again, and between 07 and 13, I lived in the RV in a campground, where I never needed to turn on the battery charger, and paid for it again. The 120 watt panels that I bought in 1999 where on sale for $429. Now you can buy that size panel for around $120. Prices have really come down!
Good luck with your project.
Fred.
