Wednesday, April 25, 2012

lenovo x60 battery REPAIRED

3 years ago i forced lenovo to send me an replacement for my x60 battery that failed just before the warranty expired. the replacement has now failed - one day it had 2 hours of runtime, the next 5 minutes, which doesn't match my model of how li-ion ages. my gut is that lenovo is artificially shutting them down on a timer (guessing they make $100 profit per replacement battery). or maybe it's a legitimate "bug". who can know. lenovo has to a degree acknowledged that it's a problem (my fru isn't listed, but it's the same symptom):

http://download.lenovo.com/lenovo/content/batt/082009/LandingPage.html

that page describes an issue with the battery controller that causes premature reports of failure, ie before the cells have died. by premature, they mean in the first year ... but really, any time the battery controller is the cause of death (and not a cell failing) it's premature. so pretty clear to me that it's *intentional* on lenovo's part, but not much that we can do about this. after all, the anti-trust division of the doj is preoccupied with it's witch-hunt against google - no way they can waste time on something as mundane as actual fraud

so i'm working under the assumption that it's a software/controller problem. some other's seem to be on the same page (http://www.levien.com/tp600-battery.html). so the deal is that if you can trick a lenovo battery into fully discharging, it will reset the controller and take a full (well, as much as the cells will accept) charge and you're back in business

but no pinout for the x60 battery, so i can't use the exact method that javier valero suggests. but i found a *simpler* workaround. while running on battery i put the machine into suspend and left it there, which drains the battery slowly. while suspended, the crescent moon led is solid green. after about 30 hours, the battery was really dead, the machine shut off and the crescent moon led went out

plugged in the ac adapter, started the machine. after a few minutes it told me the battery was 100% (even though i now know it's almost totally discharged). removed the ac adapter and waited a few minutes until the "critically low battery" warning came up and plugged it back in. the battery charged to full (24000mwh - the battery is *somewhat* old after all :) and has behaved normally since

note: during the long suspend, the machine woke up once (presumably because the battery told it that it didn't have enough juice to keep it in suspend for much longer). i plugged it in for a second, clicked "ok" (ie suspend again) and then removed the ac as soon as it went back to suspend. not sure if the ac was needed or not

  • lenovo x60, stock other than 4G ram that i installed
  • ubuntu 11.10 as the primary OS, windows xp still installed and occasionally used
  • battery: FRU P/N 42T4631, ASM P/N 92P1170. fewer than 50 charge cycles (the x60 is usually plugged in). this battery was supplied by lenovo under warranty 3 years ago, but my original battery had a similar failure mode
symptom: one day the battery was fine, with runtimes of approximately 2 hours. the next time i tried it (could have been a month or 2 later) the runtime was 5 or 10 minutes. and the battery would report capacity of 30000mwh slowly decreasing to say 29000, and then suddenly drop to 1000mwh, causing the machine to suspend (in both ubuntu and windows xp). from the lenovo bulletin:

  • Irreparable damage or battery cannot be charged error message from Power Manager or Message Center, or
  • Low battery capacity, as indicated by short battery run time or sudden drops in the battery fuel gauge


tl;dr -- my lenovo x60 laptop battery failed prematurely (running ubuntu). i repaired it by leaving the machine in sleep till it shut down (crescent moon led went out), charging till "full" (only took a few minutes), discharging till "critical" (again, just a couple of minutes), and then everything worked normal, battery would hold 24000mwh


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