Re: how to control battery charge level on a laptop

[mlelstv%serpens.de@localhost (Michael van Elst)]

nbsd4ever%gmail.com@localhost (Henry) writes:

>  1) design capacity is said to be 5.376Ah, but written directly on the
>battery is 7.7V, 41Wh (=~5.324Ah) and nominal 5350mAh.  While small, the
>battery is being overcharged to 5.376Ah (101%).  Is there a way to
>correct the design capacity to 5.324Ah, and force the machine to keep
>the charge no higher than 5.324Ah?

No. The value is reported by the battery.

It's also unclear if you can influence the charging process. Some
laptops (like Thinkpads) allow this, others do not. If they do,
they use some vendor-specific methods.


>  2) the CritMax and WarnMax entries are blank.  Is there a way to
>inform the machine of these parameters, and issue a warning and stop
>charging the machine until the issue is resolved?

You can set values, and this notifies powerd to trigger some action.
But you cannot stop the charging process. Best would be to play
an alarm signal telling you to remove the power cord.


>  3) the WarnMin and CritMin for charge are 12.091% and 7.068%.  What
>actions are taken, if any, when these levels are reached?

The event is passed to powerd (assuming that you run it) that then triggers
an action. Default is to run /etc/powerd/scripts/sensor_battery which
just logs the event. Falling below CritMin on all batteries while AC is
disconnected creates the additional "low-power" event that triggers a
shutdown and powers off the machine (also via that script).


>Unless there is some way to control the battery charge level, I think
>I will have to take the battery out and connect the adapter to a ups,
>since I use the PC remotely, and can't keep an eye on it constantly.

I don't think that changing the charging levels (if that's possible)
prevents your problem. Every battery will fail after some time, YMMV.

Saying that, I never had a laptop battery blow up but already two
phone batteries (fortunately without fire).