How long will single battery last with heater running?

philh wrote:
We may have our first opportunity to dry camp mid winter for one night. Do I stand a chance of surviving on a single deep cycle 12V battery, or should I just plan on buying my first i2000?

Depends on how much amp power is your furnace drawing and for how long..

I have Espar diesel heater that's probably the most efficient unit available and it discharged the battery only 20-25% down even at minus 20 C..but then I have two inches of rigid foam insulation everywhere in my small TC and double pane windows.