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warnec

Member

From: Poland

Registered: 2009-06-22

Posts: 166

Can a battery report "empty" at 20% and "full" at 90% ?

The question is as in the topic's name. I plan to buy a ThinkPad T410s with Li-Ion battery, and it is best to keep it at about 20-35% to 85-90% charged all the time, because deep discharge or full charge deplete its capacity.

So, is it possible for a laptop to report that the battery is empty when in fact the charge level goes down to a predefined value (like 20%) and report fully charged when it reaches, say, 90%?

I'm asking just out of curiosity, because it would be of great help, not having to remember about it and turning the laptop off when it reaches ~20%.
(charging to 90% is not a problem, thanks to tp_smapi, read more about it here: http://www.thinkwiki.org/wiki/Tp_smapi# … _features)

Besides, it would make it possible for me to see the calculated discharge real, just as I need it, to 20%, not 0%.

I await your answer, but I doubt it, however, because, as I presume, it would require low-level changes in the system, most propably BIOS, and nobody would tamper with that, would they?

Maybe it is possible to use some sort of system's power management programs?

As a workaround, I think writing a script which checks battery state and displays a "Your battery reaches 20%! Save your work and close the system!" (libnotify style, I'd like to use Ubuntu 10.04) warning, at, let's say, 25%. 

What do you think? Which solution is best? And, more importantly, which is possible?

eldragon

Member

From: Buenos Aires

Registered: 2008-11-18

Posts: 1,029

Re: Can a battery report "empty" at 20% and "full" at 90% ?

there is a battery monitor for the gnome-panel with a low level alarm configuration

warnec

Member

From: Poland

Registered: 2009-06-22

Posts: 166

Re: Can a battery report "empty" at 20% and "full" at 90% ?

And, this is it? No any other idea? gnome battery monitor isn't too bad, but i hoped for something more...

lagagnon

Member

From: an Island in the Pacific...

Registered: 2009-12-10

Posts: 1,087

Website

Re: Can a battery report "empty" at 20% and "full" at 90% ?

I would write  script that checks the output of "acpitool -B". This gives fairly accurate % remaining numbers.  "pacman -S acpitool", then write a script that periodically checks its output, greps the % level and then maybe use zenity to send you a message when it gets to 20%.

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Painless

Member

Registered: 2006-02-06

Posts: 233

Re: Can a battery report "empty" at 20% and "full" at 90% ?

GNOME's gconf allows you to set the thresholds for when your laptop shuts down or hibernates.

Applications -> System Tools -> Configuration Editor

Apps -> Gnome Power Manager -> thresholds

You can also specify the actions in Apps -> Gnome Power Manager -> actions

demian

Member

From: Frankfurt, Germany

Registered: 2009-05-06

Posts: 709

Re: Can a battery report "empty" at 20% and "full" at 90% ?

I think that's a very bad idea. Batteries are consumables and should be treated as such.
In my experience a modern Li-Ion battery as you can find them in ThinkPads won't lose more than 30% capacity in two years - even if you treat it badly, that is.
For instance, mine is ~15 months in constant use and still has 78 of 84 Wh.

Last edited by demian (2010-06-16 22:49:26)

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