Havahart Wireless Dog Collar Battery Replacement Kit Batteries last for up to 1,000 charges Batteries take 1.5 to 3 hours to charge Charger can charge up to 2 Batteries at once Charger can only be used to charge HWRECHBAT Batteries - Will not work with old model: HW2REBATPACK Charger's indicator light is green when the Battery is fully charged