GTA02 Battery Capacity (Was: Re: More about the GTA02)

Kyle Bassett kylebassett at
Thu Feb 14 08:38:15 CET 2008

I have been following the "Suspended Mode" thread in the kernel ML and they
have made amazing progress within the last week.  As GTA02A5 currently
stands, a "cold" suspend mode (just GSM in standby awaiting incoming
call/sms), could result in >20 days of standby!

For those technical people on this list, they have gotten GTA02A5 in suspend
using ~2.07mA @ 3.7v (fully charged batt).  If the GTA02 will have a 1200mAh
battery, that's ~24 days of suspend runtime in a perfect world.  The goal is
set around 1mA-2mA of suspend current draw, with best case scenario suspend
time of ~50 days (sure beats 4 hours... :-P  ).  There are also issues such
as internal battery discharge, ~30% over 90 days for one of the packs that
is being considered, which will reduce the final suspend runtime available.

Currently, work continues attempting to shave even more power consumption
from a sleeping Freerunner.  Individual power consumption of the different
internal devices is still taking place, that way any user can approximate
their battery lifetime (but each internal device has a few different states,
making this a tedious task).  In the very near future, we should see some
numbers coming in about the "talk" runtime, once some GSM power state issues
are resolved.

There is talk about pushing startup power control of the internal devices
(wifi, bt, gps, mmc, etc.) to user level, as every user may or may not want
certain devices available at bootup/all the time (availability vs.

It's nice to have some good news, everyone keep up the good work!


On Thu, Feb 14, 2008 at 12:29 AM, Michael Shiloh <michael at>

> Nick Guenther wrote:
> > On Feb 8, 2008 4:04 AM, Michael Shiloh <michael at> wrote:
> >> Hello,
> >>
> >> I've researched this a little, and this is what I've learned:
> >>
> >> 1. We are still looking at a number of different batteries, so there is
> >> no "final" capacity or feature set determined yet.
> >>
> >> 2. The capacity will most likely be around 1200mA.
> >>
> >> If you find any place on the wiki that says something other than
> 1200mA,
> >> can you please make the correction? You may reference this email.
> >
> > Oh. That's... really disappointing. The battery life is already
> > unusable, and the faster processor and wifi will just make this even
> > worse.
> We are well aware of software changes we need to make in order to
> improve battery and have simply not had the time to do this. You can
> expect much better battery life when we implement these changes.
> In fact if you look in the archives of the kernel mailing list you will
> see that a tremendous amount of progress has happened over the past few
> days. I think the current SVN code supports a much improved suspend mode
> that my very simple testing suggests should last for well over 12 hours.
> And work continues.
> Michael
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