Canon BP535 3500mAh Lithium Ion Battery Pack for ZR and Optura Xi Camcorders The Canon BP-535 is the largest capacity battery for Canon's ZR series, consisting at its debut of the ZR20, ZR25MC. and 30MC The BP-535 lithium ion battery can be recharged at any convenient point; it is not necessary to wait until the battery is completely discharged, as is the case with certain other battery technologies 3450 mah According to tests, this battery lasts up to 8 hours 15 minutes when the camera's viewfinder is used, and up to 6 hours 15 minutes when the LCD screen is used