I just started using a 40W portable last year. It seems to do the trick for us. Nice to be able to move it to follow the sun, as our trailer is usually shaded. We only deploy it for longer stays too, as the dual batteries alone are good for running your trailer for a few nights.
2017 Escape 5.0 TA (someday soon, I hope
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
“Most folks are about as happy as they make up their minds to be.” — Abraham Lincoln