If you had a deep cycle marine battery course you would have to charge it periodically probably every other day if I had to guess it would work in a pinch. That's what's power in this device now I think I've pretty much reached it's low temperature at least for this gallon and a half of water looks like it's going to be... 55.2. I might try larger more powerful Peltier and 2 cooling blocks as opposed to one,goal here is going to be to keep 5 to 7 gallons at least in the mid-sixties I think it's doable.. anyhow it's been fun playing with these little things going to build a freezer out of one here don't think that'll apply,☮ï¸