The easiest and most efficient way to do this is to use a deep-cycle marine battery and a pure sine-wave DC/AC inverter, which can be purchased for under $150 online. Most other power systems are square wave, which tend to produce a fair amount of 60 hz hum.

The marine battery will last about 7 years if kept charged with an inexpensive trickle charger and the battery will cost you about $150 on average.
total outlay for a solid system will be about $300. That battery will be heavy, though, about 55 pounds.


Gary