Microsoft has rejected claims that Windows 7 is a battery hog, or is delivering false warnings about faulty or depleted batteries in laptop computers.

Various tech forums and blogs have been reporting stories of messages delivered by the operating system to computer users, saying “Consider replacing your battery”. Writers have suggested that there’s nothing wrong with the batteries in most cases, and that the fault lies with Windows 7 itself.

In a blog posting, Windows president Steven Sinofsky says, “At this time we have no reason to believe there is any issue related to Windows 7 in this context.” The battery warnings, Sinofsky goes on to say, are most likely genuine.

“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,” he says.

“Using all the tools at our disposal including contacting customers reporting this issue on forums, customer service communications, partnerships with our PC makers, and of course the telemetry in Windows 7, we have been monitoring reports and discussions regarding this new feature.To date all such steps indicate that we do have customers seeing reports of battery health issues and in all cases we have investigated Windows 7 has simply accurately detected a failing battery.

“A quick check of mainstream laptops will show that batteries usually have a warranty of 12 months, which is about the length of time when statistically we expect to see noticeable degradation (meaning that you start to notice the need to charge more frequently).

“Windows 7 makes use of a feature of modern laptop batteries which have circuitry andfirmware that can report to Windows the overall health of the battery.

“There is no way for Windows 7 or any other OS to write, set or configure battery status information.In fact all of the battery actions of charging and discharging are completely controlled by the battery hardware.Windows only reports the battery information it reads from the system firmware. Some reports erroneously claimed Windows was modifying this information, which is definitely not possible.

“It should stand to reason that some customers would be surprised to see this warning after upgrading a PC that was previously operating fine. Essentially the battery was degrading but it was not evident to the customer until Windows 7 made this information available. We recognise that this has the appearance of Windows 7 ‘causing’ the change in performance, but in reality all Windows 7 did was report what was already the case.

“If you believe you are receiving this error and your battery is new or believed to be in great shape we would encourage you to report this to us or your original PC maker.”

The full blog posting can be read here, and anyone wishing to report a concern as mentioned above can use the contact form on that page. Judging from comments posted on the page, some users are not convinced by Microsoft’s reassurances.