If you have a place for a solar panel, it might be a good alternative. If you do your homework, you could make sure you have enough juice to run a small fridge.

Also, my understanding is a small chest style freezer, combined with an external thermostat are very efficient and won't lose as much heat when you open them.

http://mtbest.net/chest_fridge.html

http://www.northernbrewer.com/brewing/br...controller.html

http://www.amazon.com/gp/product/B000MSCKM6
http://www.amazon.com/gp/product/B000MS8SHM
http://www.amazon.com/Brunton-SOLARIS-Foldable-Solar-Silver/dp/B0018BCYRM

Depending on the over night heat loss, you might not need to even mess with batteries.

Random thought -- if you have power during the day, but not at night, I wonder if some sort of thermal mass might further assist keeping the target temperature.

I'm thinking about solar panels more and more these days instead of a generator. No noise, no gas to run out....

-john