I am running my ATC Bobcat shell with a single battery, the truck battery under the hood. My camper has the lights and the furnace that run off the battery. I don't use it for any other electrical in the camper. I have a standard Intersate battery that is wire to the camper connector in the bed. I was told it should be ok to run the furnace for single nights. I also carry a battery charger that I can use IF the battery runs down. My question since I'm charging and dis-charging this battery should (or can) I replace my truck battery with a deep charge battery like an Optima or something else to avoid wearing out the battery from both starting the truck and using my camper? Can deep cycle batteries be used as a primary auto battery? Thanks.