Ouch, i did not want to go back the route of 6 volt batteries again, they cost me a big chunk of change before. Half the time we have hookups, the other half, we are in yosemite and normally don't use a heater in the summer and really have no use for a battery since my kids go to bed at sunset. But dry camping for a weekend at the beach in the winter like next weekend, might not work well. Weather is supposed to be 40 degrees at night plus wind, i will need that furnace for the little guys, one battery is not going to cut it, in fact two 12volt deep cycles might not even cut it, i do have a generator i could recharge each day though.