I live in the PNW and have 100W and 2 2GC batteries. My use case is 3 day trips dry camping throughout the year and one or two extended trips where I either have shore power or the truck alternator to charge. This works ok for me, but the panel won't keep up with daily demand in the winter if I use the furnace or not. The main reason I added the panel was to keep the batteries ready to camp while the trailer is parked, which it does well. If I was full time I would want at least 250 watts.