Thursday, February 4, 2010

Windows 7 on laptops?

Are you running Windows 7 on a laptop? You may be interested to know that there's a problem with Windows 7 on laptops, where Windows effectively kills your battery. And I don't mean, "my battery just got drained to 0%, time to recharge." Instead, Windows 7 may permanently damage (2) (3) (4)your laptop battery. Even if you roll back to Windows XP - which many people have done.

Microsoft Technet has a forum thread on this topic, where users report problems with many different brands of laptops. The thread dates back to June 5 2009 - when Windows 7 was still in "Beta" - and continues to be updated with more comments. That's at least 8 months, and no fix yet from Microsoft! (Sound familiar?)

Microsoft is convinced the problem relates to a BIOS problem, but several comments in the forum suggest not.

I hope you bought a spare laptop battery.


  1. Wow. That's quite a feat - how does MS accomplish this? I would also expect modern batteries to have their own microcircuitry which disconnects the battery when the charge is below the recommended per-cell voltage; batteries without the integral low voltage protection circuitry are begging for trouble.

    I don't see how the BIOS can be blamed; the BIOS has nothing whatsoever to do with the computer's operation once the kernel initialization phase is over and the CPU is switched into a virtual mode.

  2. I like how this showed up in the beta, WHERE YOU ARE SUPPOSED TO FIND/RESPOND TO PROBLEMS LIKE THIS, but Microsoft seems to have ignored it.

  3. If it is taking them this long to address it, my guess is that they have a bug in how they handle I2C. Something as simple as suspending at low voltage should be trivial.

    To play devil's advocate, it may be a hardware problem. I built a little embedded system which uses SMART batteries, and the I2C controller did not actually do what the docs said and the spec required. Had to drill down to the level of watching the signals on an oscilloscope before I realize it wasn't properly acking. I wasn't using no-name hardware either.


Note: Only a member of this blog may post a comment.