The 4000 watt 24 volt low frequency AIMS Power inverter charger transforms DC (direct current) power, stored by batteries, into AC (alternating current) electricity that can be used to run your various tools and appliances. This inverter also has a built in AC-to-DC battery converter charger, which allows users to recharge their battery bank from an AC source such as a fuel-powered generator, shore power or a regular outlet at home. The built in battery charger features a seven type battery selector and 3 stage charging, for safely and effectively charging your battery source. Use this product for renewable solar, off-grid, mobile and emergency backup power applications anywhere that uses 110 or 120 volts of alternating current. This product also has auto frequency detection that allows users to operate at either 50 or 60 hertz. This inverter is equipped with a 12000 watt surge capacity for up to 20 seconds, specifically for devices with high startup needs, like motors, compressors and pumps.