You might want to first decide how much energy you use every day by doing an energy audit before buying panels and then having to adjust your usage to meet the panel output. It is surprising many Amp-Hrs. are consumed by just the everyday items, some of which run in the background) in many RV's.
For instance, my mid-size travel trailer uses roughly 30 Amp-Hrs. per day for items like the refrigerator, water pump, CO2 detector, clock radio backlight, bath fan, etc....all before I even turn on any lights (LED) or use the furnace. There are guys who are better at this than I am (whom I am sure will chime in), but to replace that 30 Amp-Hrs. on a daily basis, I would need roughly 75 watts of solar panels (assuming 5 hours/day of peak output) with everything (panels, controllers) operating at 100% efficiency and with no wire losses....all of which are impossible). So a 100 watt panel would not be inappropriate for me. I have 300 watts, flat mounted on the roof, but use the trailer mainly in the winter when sun is at a premium.
Hope this helps,
Steve
