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oxygen_wobble

Member

Registered: 2012-05-20

Posts: 129

Battery management for T440s (two batteries), with tpacpi-bat ?

Hi everybody,

the latest ThinkPad T440s has two batteries, one internal, one external.

Now, i followed the guide to enhance battery lifespan, as described in the T420 wiki article.

(https://wiki.archlinux.org/index.php/Le … 0#Tp_smapi)

But, with the two batteries, only one gets charged to the specified threshold, while the other one (probably the internal one ?)
remains stuck at 51% ...

Is there a way to charge both batteries to threshold, without physically removing one ?

Regards,
N

EDIT: Ok, just found out that tp_smapi isn't really supported at all, so what i'm talking about are the tpacpi-bat scripts ...

Last edited by oxygen_wobble (2015-03-10 20:11:36)

oxygen_wobble

Member

Registered: 2012-05-20

Posts: 129

Re: Battery management for T440s (two batteries), with tpacpi-bat ?

Ok, already found it ...

internal battery is number 2, external battery is number 1 ... i've got no idea if this is reliable, ot if the numbers might be changed

If you remove the external battery, the internal becomes number 1, so, primary (no wonder, really ...)

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Battery management for T440s (two batteries), with tpacpi-bat ?

My machine will charge the internal battery to somewhere around 70%, then charge the removable battery pretty much all the way, then come back and top off the internal.  It does this without any scripts or attempts to control battery thresholds.  The firmware alone handles this.

I do have various powertop recommended settings that allow for longer battery life.  But as far as attempting to control battery thresholds, I figure that all batteries wear out eventually... and that takes a bit, so why not just allow them to do what the firmware intends?

oxygen_wobble

Member

Registered: 2012-05-20

Posts: 129

Re: Battery management for T440s (two batteries), with tpacpi-bat ?

Hmm, ok, haven't really tested this, but it seems my device charges all the way up to ~99% ...

With the tpacpi-scripts, things can be controlled pretty well, except that the battery numbers seem to be changing when changing the battery whilst the device is switched off.

Runtime is still amazing, even when only charged to 80% (esp. with the large battery), so i think i'll keep it at that for now.