Microsoft on Monday issued a lengthy statement about the recent Windows 7 battery controversy, echoing my assessment from earlier in the day but backing it up with cold, hard evidence. Put simply, Windows 7 is not responsible for any battery life issues that customers have reported via its support forums.
"Windows 7 is correctly warning \[about\] 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," Microsoft president Steven Sinofsky wrote in the Engineering Windows 7 Blog. "We are seeing nothing more than the normal course of battery degradation over time ... In every case we have been able to identify the battery being reported on was in fact in need of recommended replacement."
Sinofsky explains that Windows 7 includes a battery notification that is not present in its predecessors, Windows XP and Vista. This notification recommends that users "consider replacing \[their\] battery" when the device's ability to hold a charge falls beneath a certain level. As a result, customers who previously never saw a warning were becoming alarmed after installing Windows 7 and assumed that the OS did something to cause that issue.
Sinosky also noted that Windows 7 does not write anything to a portable PC's battery. "Some reports erroneously claimed Windows was modifying \[battery status\] information, which is definitely not possible," he wrote. "This information is read-only and there is no way for Windows 7 or any other OS to write, set, or configure battery status information."
You can read the entire response on the Engineering Windows 7 Blog. (As usual with Sinofsky, it's on the wordy side.