Power inverters for cars and other vehicles can be purchased at stores that sell automotive supplies and electronics, such as Walmart and AutoZone. Power inverters can also be purchased at hardware stores.
Power inverters convert the DC power inside a vehicle's battery into AC power that can be used by electronic devices. A power inverter can charge cell phones on long trips or act as a generator during a power outage. Drivers should purchase an inverter with at least 10 to 20 percent more watts than they actually need. Power inverters under 450 watts can be plugged into a vehicle's cigarette lighter or clamped on to the battery, while inverters over 500 watts must be directly hard-wired to the battery.