[Gta04-owner] charging battery

[Dr. H. Nikolaus Schaller]

Am 23.04.2013 um 22:51 schrieb Liz:

> On Mon, 22 Apr 2013 13:12:42 +0200
> "Dr. H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> But charging current will go up a little if the battery becomes more
>> charged.
>> 
>> So I guess it was a temporary problem or something with your USB
>> chargers?
> 
> I cleaned out the power key hole and the phone didn't do such strange
> things
> Now Battery 0 is being recharged after discharge overnight to 6%
> plugging in any power at that stage did not start charging the phone
> I had to shut it down and restart to allow charging.
> 
> Is this other people's experience?

You may be hit by this issue:

if there are power fluctuations and the USB voltage drops below ca. 4.5V
even for a very short moment, the charger stops. And is not restarted unless
the power drops below some lower threshold where the USB subsystem
detects that the cable has been unplugged. So USB thinks everything is ok
while charging has stopped. And since charging is started by the USB
plug-in detection it will not come out of this situation autonomously.

IMHO this is a bug in the design of the charger and USB drivers...
It is possible to disable this auto-switch-off of the charger but I was convinced
by the kernel specialists that this is harmful.

There is a test to find out if this is the problem. If you use the latest NAND
image (you can also copy it to an SD card and boot from SD), issue this
command:

/boot/batt 10

it will report every 10 seconds the status of the important charger and battery
values. This will show if the VBUS will fluctuate and drop and it will show
the state-change if the charging stops.

Hope this helps to debug the issue.

-- hns