[Gta04-owner] various powermanagement issues

Andreas Kemnade andreas at kemnade.info
Sat Oct 17 12:15:25 CEST 2015


On Fri, 16 Oct 2015 20:05:07 +0200
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> > Monitoring device current:
> > My last boot from flat battery took >10h even with my bike-approved
> > initrd setup.
> 
> Depends if your device goes to suspend or not. If it does not, it will draw ~400mA.
> And USB charging is limited to 500mA (unless increased to 800mA). So there
> are 100 mA for charging of a 1200mAh battery. Should make 12 h.
> 
I was not talking about charging the battery full. I was just talking
about boot(!!) time from
adding usb power input 
The battery is so bad that after precharge the battery has not enough
power to start booting the kernel most times. So it is really time to
be replaced...

root at gta04:~# cat /sys/class/power_supply/bq27000-battery/charge_full
389130


> > My battery seems to have lost much capacity the last
> > weeks. I guess I could still find GTA02 batteries somewhere but not for
> > a long time. So the questions are:
> > 
> > - Are there any other hints for current other than montioring IUOS
> > mhile in CV charge mode?
> 
> bq27000 through hqd should report.
> 
Well, I was just thinking about living without the special openmoko
battery,
so there is no bq27000.

> > - Has anyone designed things like a BQ27000 adaptor to put a little bit
> >  smaller standard battery into the GTA04 and that adaptor between the
> >  adaptor board?
> 
> Not that I am aware of. But it is an interesting idea! You would just have to design
> a tiny PCB with two spring contacts on one side and 3 gold contacts on the other.
> A shunt resistor and the bq27000 in between. Maybe even embedded in the
> PCB (which should be just 0.5mm thickness...).
> 
Hmm, AFAIK the schematics+ of the Om battery are open, so that should
be a starting point.

> But beware to make it short-circuit *safe*. And, you have to program the bq27000
> so that it "knows" the nominal capacity. I don't know how easily that can be done.
> 
You mean taking care that at least one short circuit protection is in
the line if you do not know if there is one in the battery?

Regards,
Andreas
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