I have 3x160w on my roof but live and camp in an area that is frequently overcast and mostly tree covered. Since I am close to the 49th Parallel, I also have limited daylight in the winter. This is probably the most adverse conditions for solar and count my actual collection close to half my rating. Once Summer hits and we head to clearer skies, generator use is limited to AC and cooking since I have not spent the money on an inverter large enough for either. I can charge through the truck, solar, generator or shore power but my battery bank comes to me used after five years of standby in a server room (however free of cost). They are less efficient and heavy, but I find even my limited power collection in Winter is enough to limit generator usage to cooking and it keeps up with my furnace fan draw.