MacRumors reports that the testing build of OS X 10.8.2 completely restores battery life to OS X Lion levels
The big change came with 10.8.2, which is still undergoing developer testing. Using the latest build, 12C35, we saw a tremendous increase in battery life, to the point where running time was a few minutes longer than even that of 10.6.8.OS X 10.8.2 Restores Notebook Battery Life to OS X Lion Levels
In addition, the study shows that users experienced a similar but smaller effect on battery life with the introduction of OS X Lion, an issue that was not fully resolved until the release of OS X 10.7.3 over six months after the public debut of OS X Lion.
