Powered for success! One of the keys to SimplyGo's portability is its lightweight and compact battery. This powerful lithium ion battery is fully charged from empty in only 2 to 3 hours and weights just 1-1/2 pounds. SimplyGo's battery is immediately accessible and can be easily changed. There are no awkward external battery belts or connectors that get in the way, or hard-to-maintain internal batteries. After the initial charge via AC power, the batteries can be charged in the unit while plugged into AC or DC power. Or, out of the unit, they can be charged using the external battery charger (optional accessory). The lifetime rating of the SimplyGo is 300 full charges.