Before going on an rv trip, I decided to install an rv solar panel kit so that I wouldn't have to depend on external power sources. I installed the panels on the roof, and on the first day, they charged the batteries almost to full. We could easily use the lights, and the refrigerator, and even charge our phones. Even on cloudy days, the panel continued to give at least some energy, and we didn't have to worry about finding outlets or chargers.