A power inverter changes DC power from a battery into conventional AC power that you can use to operate all kinds of devices ... electric lights, kitchen appliances, microwaves, power tools, TVs, radios, computers, to name just a few. You just connect the inverter to a battery, and plug your AC devices into the inverter ... and you've got portable power ... whenever and wherever you need it.
The inverter draws its power from a 12 Volt battery (preferably deep-cycle), or several batteries wired in parallel. The battery will need to be recharged as the power is drawn out of it by the inverter. The battery can be recharged by running the automobile motor, or a gas generator, solar panels, or wind. Or you can use a battery charger plugged into an AC outlet to recharge the battery.