I have an idea on how to warm a tear drop with out using your battery up, you know how you always have a fire going, well what would happen if you had a rock about the size of a large grapefruit heating in the fire till you got ready for bed, and the you took it out of the fire and put it in say a dutch oven ad put that in the trailer, as small as the trailers are, it should be enough to keep it nice and toasty if it isnt, you could just use more rocks.
