[ltp] Re: ThinkPad Batteries

Elias Oltmanns linux-thinkpad@linux-thinkpad.org
Thu, 13 Nov 2008 00:09:00 +0100


"Daniel Castro" <castromd@tcd.ie> wrote:
> hey!
>
> another thing...
> i'm trying:
> echo 30 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
> echo 80 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh
>
> but I noticed that when it reaches 79% it stays there, it will not get to
> 80% and it will never start discharging...

It doesn't always reach exactly 80%. This is nothing to worry about but
just a consequence of the fact that capacity measurements aren't an
exact science, to put it in that hand wavy way. Also, it won't discharge
as long as you are connected to main power.

>
> so I did:
> echo 95 > /sys/devices/platform/smapi/BAT0/start_charge_thresh
> echo 100 > /sys/devices/platform/smapi/BAT0/stop_charge_thresh

Whatever for?

>
> and left it to charge to 81% and then did the 30-80 one again.... and it is
> stuck there in 81%....
>
> i though that it would charge up to 80% and then run on battery until it
> gets to 30%, then charge again to 80% and so on... isn't that what's
> explected?

No, that would be just crazy. It charges until it has reached the upper
limit and leaves it there, using main power as long as it's connected.

Regards,

Elias