Apple has posted an update for the battery of the MacBook and the MacBook Pro line-ups which increases performance.

Battery Update 1.2 updates battery firmware and improves battery functionality.

After Battery Update has been installed, each battery you insert into your MacBook or MacBook Pro will be updated automatically. Your computer's power cord must be connected and plugged into a working power source.

For further information on this Update, please visit this website: http://www.info.apple.com/kbnum/n305256

The 244KB file is available from Apple's support web site.

The company has also issued a repair program for certain batteries that lose their power prematurely. Users who encountered problems as described in this support page may contact Apple for a free replacement even if the warranty has ended.