We went on a month long trip last year with a 5 cu ft chest freezer in our 5er running on a 1,000 watt PSW inverter all day and I would check on the freezer at every stop which were many and the compressor was hardly ever running. We have a single 12 volt battery. At night we had shore power & I would run the freezer on shore power and when we would hit the road in the morning the battery was just abt. full charge and I would put the freezer back on the inverter. This was a experiment, and now I will make the wiring permanent. Seriously considering a residental fridge when the time comes along with either a 2nd 12 volt battery or switch to 2 6 volt batterires. I know not exactly what you want to do but may give some idea. By the way the freezer only draws less than 2 amps. :)