World’s longest lasting AA and AAA battery for high-tech gadgets. “Delayed at the station? Get pedalling to cost your phone”. To recharge a fuel vehicle’s starter battery, where a modular charger is used; usually an 3-stage charger. For cell phones with detachable rear cover, extended batteries exist. These are bigger inner batteries attached with a devoted, more spacious rear cowl changing the default one. A drawback is incompatibility with different telephone instances while hooked up.