I don't bother trying. You shouldn't be in a camper during the day anyways!
Seriously, I've only got a single 13.5 on our 32 footer bunkhouse. I did some workamping in NJ This summer averaged 110 in the sun all day. Once the sun dropped the AC cooled the camper quickly, and by the morning it was like a refrigerated box car.
Don't bother wasting the energy, camping should have a certain amount of "green" factor, right?
2007 Chevy 2500HD crew
2015 Jayco Jayflight 32BHDS