Re: [Debconf-discuss] X60s battery issues
+++ Luca Capello [2011-07-26 15:54 +0200]:
> Hi there!
>
> On Tue, 26 Jul 2011 13:26:54 +0200, Chris Knadle wrote:
> > On Tuesday, July 26, 2011 02:53:25 AM, Jérémy Bobbio wrote:
> >> It looks like the battery of my laptop (ThinkPad X60s) does not want to
> >> charge anymore.
> > I'd like to believe that the battery could be recovered using some kind of
> > ThinkPad battery firmware hack, but I haven't been able to find one. I
> > similarly have a failed battery that I'd like to bring to life again. [If
> > anhyone has a clue on this, please ping me via email.]
It might be possible. It will only be possible for a relatively short
period of time (days, maybe a couple of weeks - after that it really
will be dead). I have tried this on batts left flat for too long with
zero success.
(note some of this is stuff is generic lithium cell/batt knowledge,
rather than specific thinkpad thnowledge, so I could be wrong - there
may be proper expert along soon). The reason for not-charging can be
due to the laptop firmware or internal batt controller deciding that
chargin is not allowed rather than anything wrong with the battery
cells as such. The firmware has a minimum permitted voltage cut-off
below which it simply refuses to charge. If your batt has got into
this state then it may well actually be knackered, but it is possible
to manually tickle it back up over the limit (with a very low charge
rate) and then the laptop will carry on using it as normal (until the
next time).
The min voltage is found in:
/sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/voltage_min_design
> I clearly remember that Henrique de Moraes Holschuh (cc:ed,
> ThinkPad-ACPI upstream maintainer) told me at DebConf9 that is there
> actually a way to "bare metal" manually charge dead ThinkPad batteries
> if the EC controller is not dead (technical details may be wrong, but
> you got the idea). I have never tried looked for the necessary
> information nor tried that, but I will certainly to that. Links
> appreciated ;-)
Here are some:
thinkpad battery pinout:
http://pinouts.ru/Power/thinkpad_battery_pinout.shtml
Useful desc of how SMBus/SBS batteries work:
http://batteryuniversity.com/learn/article/inner_workings_of_a_smart_battery
I don't actually know if the IBM system uses SMBus or something
they made up themselves. I expect it to be very similar though.
cat /sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/uevent
will give you some clues to current batt state.
I expect you'll find that
/sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/voltage_now
is lower than
/sys/bus/acpi/drivers/battery/PNP0C0A:00/power_supply/BAT0/voltage_min_design
The old thinkpad_acpi module had low-level debug you could turn on -
which may have been helpful - but I'm not sure what's available in the
current in-kernel implementation.
Ah I see that Mr Holschuh wrote the driver. I guess he should know how
it all works :-)
Wookey
--
Principal hats: Linaro, Emdebian, Wookware, Balloonboard, ARM
http://wookware.org/
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