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

Michael Shiloh michael at
Thu Feb 14 08:50:40 CET 2008

Thanks Kyle for a great summary of the work being discussed on the 
kernel ML. I am simply not able to keep up with all the lists and very 
much appreciate your helping out here.


Kyle Bassett wrote:
> 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. duration).
> It's nice to have some good news, everyone keep up the good work!
> -Kyle
> On Thu, Feb 14, 2008 at 12:29 AM, Michael Shiloh <michael at 
> <mailto:michael at>> wrote:
>     Nick Guenther wrote:
>      > On Feb 8, 2008 4:04 AM, Michael Shiloh <michael at
>     <mailto: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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