Deep Discharge et al.

Harald Welte laforge at
Thu Dec 20 17:22:23 CET 2007

On Wed, Dec 19, 2007 at 04:17:10PM -0500, Nick Guenther wrote:

> > Does the neo actually know how much power is left in the battery?
> Well, it knows whatever the apm subsystem reports. That part is pretty
> accurate, the inaccurate part is the attery's own measurement of
> itself. This is a general problem with batteries, and not the neo...
> except I don't know how good the neo's detection is afterall, can
> anyone on the hardware team comment on that?

GTA01 doesn't have accurate battery charge/discharge metering, just the
current cell voltage.  From this, the amount of charge left in the
battery can be estimated based on calculations.  However, the latter is
currently not implemented to the best of my knowledge.

So the battery scale will make the completely wrong assumption that it
is linear with regard to the voltage.

GTA02 has a coulomb counter in the battery, enabling precise

Patches to improve GTA01 are welcome :)

- Harald Welte <laforge at>         
Software for the world's first truly open Free Software mobile phone

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