For extended power needs, you may want to have an extra system battery
The ThinkPad A Series Lithium Ion System Battery is a rechargeable battery that supports the ThinkPad A Series. This battery contains 9 cells providing an output of 10.8 V and can be recharged in 2.0 to 5.0(1) hours depending on the ThinkPad system usage. Spare system batteries can be swapped in to maximize "unplugged" system usage.
Operates and recharges in the battery slot of the ThinkPad - Can be swapped out with the standard system battery to extend the unplugged usage time of the ThinkPad (always have a fresh second battery on the ready to let you keep using your ThinkPad)
Battery Capacity : 3.2 Ah
Recharge Time : 2.5 Hour(s)
Weight: .59 lbs
Dimensions: 1.02"(H) x 2.47"(W) x 7.47"(D)
Warranty : 1 Year
BRAND NEW FACTORY SEALED & RETAIL BOXED