HP 12-Cell Multi-Charge Extended Battery. Recharge whether your notebook is on or off. It offers up to 8 hours battery life. Check your battery charge with the new fuel gauge. Plug in your battery to AC adapter port to recharge.Compatibility: HP Pavilion: dv4, dv5, HP HDX: HDX 16 HP: G50, G60, G70 Compaq Presario: CQ40, CQ45, CQ50, CQ60, CQ70. Battery Re-Charge Time: System in OFF or Standby Mode: 4.5 hours System On: 5 to 8 hours.