Back in February, it was reported that there was a bug in Windows XP SP2 concerning battery life and laptops. Originally it was attributed to the Intel Core Duo/Centrino platform, however that turned out not to be the case – it was simply a problem with Windows XP SP2 and USB controllers (particularly those that stayed on for some reason). This fix is for 32-Bit Windows XP only (both Home and Professional versions). It’s highly recommended that you take a look at this fix if you have a laptop and Windows XP SP2 and think there maybe something funny with your battery life.
Information from Microsoft:
Symptoms: When you unplug the AC power from a Microsoft Windows XP-based portable computer, the battery may drain more quickly than you expect. Therefore, the operating system may shut down prematurely.
There are three potential causes:
– The portable computer cannot enter the deeper Advanced Configuration and Power Interface (ACPI) processor idle sleep states.
– The USB host controller is unable to turn off.
– The USB host controller uses the periodic scheduler for USB 2.0 devices.
The fix is available here (support.microsoft.com).