Carry a spare ThinkPad X60 Tablet 4 Cell Li-Ion Battery so you can stay unplugged longer! The 4 cell battery delivers approximately three hours (1) of unplugged time. Need even more freedom? Consider the ThinkPad X60 Tablet 8 Cell Li-Ion Battery (40Y8318) for approximately seven hours (1) of system run time. (1) These model numbers achieved Battery Rundown Time of at least the time shown during testing. A description of the testing available at lenovo.com/pc/ww/thinkpad/batterylife. Battery life (and recharge times) will vary based on many factors including screen brightness, applications, features, power management, battery conditioning and other customer preferences.