Consider a wind charger if you are leaving your camper in a static location. I have left my old camper on the same site for 6 years. I use it year around and here in ND it can get chilly at night. I started with 2 deep cycles battery's and a 100 watt solar charger. I found that the recharge with the short days in the winter just was not enough. I put a 400 watt wind charger up 4 years ago. It has a built in controller and keeps the battery's charged very nicely.
I use the camper at temps down well below zero. I put 4 ft. high plywood skirting with R-8 insulation around it, put fiberglass in some of the north and west windows and on the cold nights the furnace runs about 4 times an hour to keep it above 70. Since I added the wind generator I very seldom run the generator. Spent 500.00 on an Air dyne charger, got surplus 2 inch poles, buried a 10 foot treated 4X4 4 feet in the ground, clamped the 2 inch pole to that, 3 guy wires and put the charger 24 feet in the air. No problems. Almost always some wind here. Well worth the money.
