A power inverter is a device that converts DC power (also known as direct current), to standard AC power (alternating current). Inverters are used to operate electrical equipment from the power produced by a battery. DC power is what batteries store, while AC power is what most electrical appliances need to run so an inverter is necessary to convert the power into a usable form. For example, when a cell phone is plugged into a car cigarette lighter to recharge, it supplies DC power; this must be converted to the required AC power by a power inverter to charge the phone.
Most domestic or industrial inverters come with jumper-like cables so they can be connected directly to a battery. This type is required to run more powerful equipment, such as power tools at a remote work site or a larger TV. Inverters can also be hard-wired into a battery to make them easier to use with larger pieces of equipment.
Larger inverters are used to convert solar or wind energy into AC power that can be used in a home. Called a grid-tie inverter, this device links into the utility grid to allow power to be delivered along the same wires that supply energy from a electric utility. It even allows any excess power produced to be fed back into the grid, where it can be sold to the utility company.
Different models of power inverters vary in how many watts of power they can supply. The capacity of an inverter should equal the total number of watts required by each device, plus at least a 50% addition to account for peaks or spikes in the power draw. For example, if a DVD player draws 100 watts and a small TV another 100 watts, a minimum 300-watt inverter is recommended. Getting an inverter with more capacity than what is immediately needed is a good idea for many people, as it means that different or new devices can be added without the need for a new power inverter.
Power inverters should only be used with batteries that are in good condition and fully charged. A weak battery will be drained easily if demand is too high. Working with large batteries can be dangerous, and when not done properly, can result in serious injury. Improper use of a power inverter can even lead to electrocution. For safety reasons, someone attempting to hook an inverter directly to a battery should be sure to read and follow any and all safety precautions listed in the inverter's instruction booklet. It is important for people to always use a power inverter that is rated high enough for the device that needs to be run.
