We boondock a lot in the adirondacks. We used to have trouble making the battery last even though we used no dc powered devices (lights, water pump, radio, etc.) the only things we used were the co detector and the refrigerator (on gas). Turned out the refrigerator had a heat element in the door to prevent condensation and it could not be turned off. Check your manual to see if your heater element can be turned off. If it can't, you can disconnect the wire providing power to the heater. Search this forum for instructions to do it if you can't figure it out from your manual. Without the heater we have never had condensation problems. In Michigan I doubt you would either.