Re: Script to monitor battery status on X220

Hi,

On Friday 20 July 2012 16:13:56 Matthias Apitz wrote:
> El día Friday, July 20, 2012 a las 03:45:23PM +0700, Erich Dollansky escribió:
> 
> > > ... 
> > > Is it necessary to poll? Usually devd generates an event when the
> > > battery status and/or percentage changes. Just read the events from
> > > /var/run/devd.pipe.
> > > 
> > this is a good idea. I did not like this solution either but did not get a better idea when I did it.
> 
> I wrote and used something similar for my netbook EeePC 900; it turned
> out that the battery is not showing the remaining capacity in a linear

this is also true on the X220.

> way; the last 5% are 'consumed' in a few seconds, i.e. below 20% I
> polled every 2 seconds;

I did some tests until I ended at the 2%. There was always enough energy left in the battery to restart the machine.

I wonder anyway how they do it. I developed battery monitors a long time ago. As the voltage drop is not linear and the tolerances are very high. They might calibrate each battery when it reaches certain levels.

Erich