Ha!! Guess I'll skip the battery idea. I'm in NC and this will be my first winter here, so we'll see how cold it gets in the mountains. A friend in WI told me he tosses a hot rock into the water and that helps. I'm thinking of wrapping a bucket of water in insulation (like for a water heater) filling with warm water and a hot rock. Figure that'll do the trick. When I try this next year, we'll find out 
