Windows 7 and battery life issues – Problem explanation and solution

Windows 7 users who were upgraded from Vista were facing a strange problem. After the upgrade battery was failing and a message was displayed “consider replacing your battery”. Now Microsoft has confirmed that it has nothing to do with upgrade but this confusion is because of an advanced feature in Windows 7.  Windows 7 had introduced  battery notification message which created the confusion.

Microsoft Explanation as follows:-

Those of us that have owned the same laptop  for a couple of years and taken it through regular charge cycles have no doubt “felt” the decline in battery life though we might have attributed to any number of factors since we did not have any information available to us otherwise.

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. 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 5 hours of charge now delivers, on average, approximately 2 hours of charge.  The Windows 7 the 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.

Tags: microsoft, windows 7