Apple Releases Battery Update 1.4 for All MacBook Models
Apple on Monday released Battery Update 1.4, an update for all MacBook models designed to improve the ability of MacBook batteries to maintain a charge when shut down and not used for an extended period of time.
To determine if you need the firmware update, Apple says to open System Profiler on your MacBook and click on Power under the Hardware section. If you see a device name of ASMB016 or ASMB013 in the serial number, a Pack Lot Code of 0002, and a battery firmware version of 0110, your battery needs updating.
To run the update, you must be using OS X 10.5.6.