Microsoft: Windows 7 Isn't Killing Batteries

Microsoft has said that the battery problems currently plaguing a number of Windows 7 users are not caused by the operating system.

Last week Microsoft said the company was investigating whether or not Windows 7 caused laptop battery life to deteriorate. People who have installed Windows 7 (stretching back as far as the RC release last June) say that their computer's battery life has taken a huge hit. One user reported that before Windows 7, he used to get seven hours of battery from his brand new laptop. Once he had installed Windows 7, it dropped to four hours on a full charge and even then, it was an optimistic four hours. Others said their laptop was telling them to replace their battery altogether.
Microsoft yesterday posted to its MSDN blog network and explained that to the best of its knowledge, Windows 7 is not destroying customers' batteries.
"Several press articles this past week have drawn attention to blog and forum postings by users claiming Windows 7 is warning them to “consider replacing your battery” in systems which appeared to be operating satisfactorily before upgrading to Windows 7," Microsoft says. "These articles described posts in the support forums indicating that Windows 7 is not just warning users of failing batteries – as we designed Windows 7 to do this – but also implying Windows 7 is falsely reporting this situation or even worse, causing these batteries to fail."
The company clarifies that this is not an issue with Windows 7:
"To the very best of the collective ecosystem knowledge, Windows 7 is correctly warning batteries that are in fact failing and Windows 7 is neither incorrectly reporting on battery status nor in any way whatsoever causing batteries to reach this state. In every case we have been able to identify the battery being reported on was in fact in need of recommended replacement."
Microsoft goes on to explain how the battery replacement warning works, detailing that Windows 7 has a set threshold of 60 percent degradation (that is the battery is performing at 40 percent of its designed capacity). When your battery reaches this level of degradation, Windows 7 will suggest you replace your battery.
The company reiterates that this is a feature exclusive to Windows 7, so folks running Vista or XP could have thought their battery was fine, when in reality it was deteriorating the whole time.