Strange and annoying battery problem with Thinkpad W520

I've had my W520 for a while and it has recently started having a strange problem. Basically, at seemingly random intervals, it seems to think that its battery is dead and it hibernates, even if the battery is actually full or nearly full. When I turn it back on it says it was shut down due to low battery. It does not do this when the AC adapter is plugged in. I haven't changed the settings for when it's actually supposed to shut down if the battery gets low. Any ideas? Thanks for looking.

 

I had this happen on my T420s a couple of times some months back but not within the last month or so. Are you using the latest available BIOS and power management software / driver? I wonder if my occurrence of the problem was fixed by the updates I did in July / August.

John

 

I've had this issue every once in a blue moon on a few different Lenovo machines. Something with their power management hardware/software. I've also had it think it's on battery every so often while it's plugged in (the screen will dim and the lenovo power manage will start reporting a time remaining, then 15 seconds later it flips back to "plugged in"). Both these problems have been pretty rare, but I have seen them from time to time.

I set my power plan to "do nothing" when the battery is low and have had no issues from it. Slightly annoying but not a huge problem.