How to Run a House Appliance Off of a 12 Volt Battery

Determine which power inverter to buy. If you're buying it specifically for one appliance---say, a refrigerator--check out the tag on the back of the refrigerator to find its wattage rating. Small refrigerators need around 60 to 100 watts. If your appliance only shows an amperage rating, multiply this number by 110. This gives you wattage. Buy an inverter with a rating slightly larger than your wattage needs.

Plug your inverter into your vehicle's cigarette lighter or a 12-volt charger outlet. Usually, inverters rated 400 watts or less have this type of plug. For bigger inverters, hardwire the inverter with cables hooked directly to the battery. Use at least a 4-gauge wire for lengths up to six feet, and 2-gauge for anything over that. Attach the cables to the battery using ring terminals, available at any auto parts store.

Plug your appliance into the inverter and turn it on. Depending on your battery and the wattage of your appliance, your battery can run down in as little as an hour. Deep cycle marine batteries generally have a higher reserve power rating, last longer, and can withstand repeated recharging.