[Gta04-owner] Battery capacity calibration

EdorFaus edorfaus at xepher.net
Sun Nov 25 19:57:22 CET 2012


On 11/24/2012 05:47 PM, Joachim Meyer wrote:
> Am Sonntag, 28. Oktober 2012, 10:58:43 schrieb EdorFaus:
>> On 10/28/2012 12:19 AM, EdorFaus wrote:
>>> My question then became: how do I calibrate it?

>>> Despite my misgivings, I'm currently trying just that, having charged it
>>> as high as it goes and am currently leaving it on and disconnected to
>>> see if running it all the way out helps. I'll report back when it's
>>> done.

> I have 2 OpenMoko batteries, an older (1) and a newer (2) one. For battery 1,
> QtMoko shows the charge indicator, but for battery 2 always the red outline of
> the battery icon and, e.g., /sys/class/power_supply/bq27000-battery/capacity
> is not available.
>
> Probably, bq27000 is still learning the characteristics of battery 2...

Sounds like it, yes.

It would be nice if the new batteries came already calibrated, but I 
guess there are reasons they don't (e.g. that the calibration would 
likely be wrong by the time the battery arrived, or something)...

I wonder if there's any official information on how to calibrate these. 
I haven't been able to find any, but I haven't explicitly asked Golden 
Delicious directly either, so I suppose it's possible that they might 
have some info stored away somewhere...

> I had already charged it until
>    cat /sys/class/power_supply/bq27000-battery/capacity_level
> showed "Full". Then I left QtMoko v49 running without locking the screen to
> let the battery run empty.
>
> Any other hints how I could help bq27000 with battery calibration?

Well, one thing I probably forgot to mention is that, before leaving it 
on for the night, I changed the power settings in QtMoko so that it 
wouldn't automatically suspend when left unlocked on battery power (it 
normally does, locking just makes it happen a lot faster).

Then I left it overnight, IIRC, and maybe most of the next day as well 
(I don't quite remember anymore), even after it had already turned off, 
just to make sure it was really empty.

Then connect it to power again, and let it charge. I turned it on fairly 
early during this charging, at which point it still didn't show any 
battery info. I was actually writing an email about that (which tends to 
take me a while), when I noticed it had started showing the capacity level.

That's all I did, so if you've done the same but it didn't work for you, 
then I'm afraid I don't have any other possibly useful hints.


I suppose I could mention that I still get the red box with no capacity 
data sometimes, when the battery is almost empty (probably so empty that 
it's just about completely empty), and for a short while after that 
while recharging it.

I don't know why, or if there's anything to be done about it, so I've 
mostly just accepted it as something that just is that way.

I guess the battery holds a charge slightly better than the bq27000 
thinks, or maybe the GTA04 manages to run (well, at least stay in 
suspend) on a slightly lower voltage than the bq27000 interface 
requires, or something.

*shrug*

-Frode


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