[Gta04-owner] uptime of rtc (unusual usage pattern)

e.waelde ew.ng7125 at nassur.net
Wed Feb 13 09:37:25 CET 2013

thanks for your reply.

On 02/11/2013 10:59 AM, Dr. H. Nikolaus Schaller wrote:
> Am 09.02.2013 um 18:44 schrieb e.waelde:
>> Hello,
>> after talking briefly to someone at the FOSDEM stand, it
>> was suggested to raise this here.
>> Q: How long is the onboard RTC supposed to run, when the
>> battery is removed from the GTA04?
> only as long as you need to swap batteries.
> The GTA01 and GTA02 did have its own 10mAh LiIon
> battery cell and that did last much longer than the Supercap
> we have in the GTA04.
> So you may ask why we did change it? The reason is that
> such batteries are no longer produced because it is too
> difficult to get them as production reels into air freight
> (LiIon is potentially dangerous as you can see with the
> Dreamliner).
Thanks for the information.

>> Background:
>> I do carry the phone (GTA04) with me almost all the time,
>> however, it is switched off. I don't need it to be available
>> to others. After finding out that the battery on gta04 drains
>> rather fast even after shutting down the device, I do remove
>> the battery from the case.
> Opps, that should NOT be the case. If the system is shut down
> through the TPS power controller and the Modem is properly
> shut down, the full system should not draw more than some
> uA. If it does, there is some bug in the shutdown software.

Ok, I took your information as a trigger to test this again:
I did a full load on Sun evening, then I shut down the device
(long press on power, select "shut down the device").

I booted it up on Mon morning, the battery indicator was
still green at approx. 80% or so (hard to judge visually).

on Mon evening the battery indicator was at approx. 40%.

just now (Tue morning) I bootet it again, the battery indicator
was red at approx 10%.

So lets for the argument assume that the battery in the 
*shut down* device lasts 40 hours. That would mean that
I had to charge the device every 2 days.

This is far away from the gta02, which I could leave shut down
for at least 14 days without being afraid of the battery
being empty.

1. My battery is really worn out. How to jugde?
   I do have a second battery which I can test. But so far
   I have not had any hints that one of them would behave
   significantly different.

2. something is not shut down after all
   I do remember a discussion about the gsm modem not being
   shut down properly, however I would need to search the

FWIW: this is with QtMoko v52 armhf. Before that I used v50 armel,
and initially v49 iirc. The behaviour was the same. A SIM card
is inserted.

3. none of the above.

Any further ideas anyone?
Anything I could check?

>> So when I want to use the phone, I boot it. However, if I
>> remove the battery for more than 12 h or so, the time on
>> the device is back to 2000-01-01 00:00:00. I used to switch
>> off the phone for maybe 2 weeks on average, but losing time
>> annoys me.
>> Any ideas?
> Well, I run ntp and 30 seconds after booting and connecting
> to a USB host with IP forwarding the clock is correct again...

At home this is how I do it as well. However, I do not
have a data connection via gsm. And this is usually, when
I need it most.


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