News | 10 Feb 2010 :
Microsoft has issued a detailed denial to accusations that Windows 7 is harming laptop batteries.
Several blogs and forums have claimed that Windows 7 is having a detrimental effect on laptop batteries, with the operating system issuing repeated warnings that a previously healthy battery needs replacing. However, in a detailed blog post on the Engineering Windows 7 site, Microsoft claims that there's no fault with the OS.
"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," Windows chief Steven Sinofsky states. "In every case we have been able to identify the battery being reported on was in fact in need of recommended replacement."
Microsoft says the confusion has been caused by a new warning system in Windows 7, that's designed to warn users when a battery's nearing the end of its useful life.
"Windows 7 makes use of a feature of modern laptop batteries which have circuitry and firmware that can report to Windows the overall health of the battery," Sinofsky writes. "This is reported in absolute terms as Watt-hours (W-hr) power capacity. Windows 7 then does a simple calculation to determine a percentage of degradation from the original design capacity. In Windows 7 we set a threshold of 60% degradation (that is the battery is performing at 40% of its designed capacity) and in reading this Windows 7 reports the status to you.
"At this point, for example, a battery that originally delivered five hours of charge now delivers, on average, approximately two hours of charge. The Windows 7 notification is a battery meter icon and notification with a message 'Consider replacing your battery'. This notification is new to Windows 7 and not available in Windows Vista or Windows XP."
Sinofsky claims Microsoft has thoroughly examined telemetry from Windows 7 customers and held lengthy discussions with key PC manufacturers to ensure that Windows 7 is not harming batteries. "Our OEM partners have utilised their telemetry (call centre, support forums, etc.) and have let us know that they are seeing no activity beyond what they expect," he claims.