We have 160 W of solar (sorry, earlier post said 120W, brain fart). And it's enough to keep up with our use until the fall. then a double wammy, less sun, and needing to use the furnace in the AM. That combo ends up with a loss of about 6% of capacity/day.
But in the summer and sun, it's enough for LED lights, parasitic draw, DW using the hairdryer every few days, and using the microwave on the inverter to heat up leftovers, maybe 10 minutes/day.
Our biggest issue, and the reason we went portable is that most of the places we camp, the trailer is in the trees and shaded so roof mount doesn't work out well. So... it's LONG cable to get us into the sun. Last year it was 50ft max, now I've got 100ft and the small additional loss with proper cable size is more than offset with more time in the sun and getting to a spot where I don't have to move it during the day.
And at least with the portable we can orient for maximum solar output, flat panels in the far north take a big hit in output in the fall.
but then we have to put up with the hassle of portables and they don't charge while traveling like a roof mount does.
So, it's a compromise, what works best for each use case.
