Pandora stops charging


b_o_b

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Sep 7, 2010
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1,493
Hi

One of my Pandora's has an issue with charging. It stops charging after a while and then starts discharging while being plugged in. Battery gives health 90% in System Info - Power use 3100 while charging and temperatue 29.5

If it starts discharging plugging in the adaptor again restarts the charging process. I also needed to reflash my Pandora twice in two days (due to hang after booting). Might be caused by the continues restarting / charging on/off and charging - dischargin while only being  0 - 1 % charged.

Any solution or advise how to determine the root cause?
 
Yeah, that's a good idea, to reset the charging logic on board.

It's normal that the charging circuits will stop charging when it's nearly full and let it discharge a little - that's designed to extend the battery life. Unplugging and replugging the charger in will normally start it charging again temporarily at least.

It's possible the battery logic has lost what full and empty are on that battery, due to reboots and plugging/unplugging. After you've left the battery out a while, put it in and leave the unit on charge for a day or so.
 
Currently having 2 pandora's side by side running the excellent System Info from _wb_

The Pandora with the charging issue started with a few minutes of discharging but then started charging again. The other one didn't have a discharging phase and is charging a lot faster but based on some comments in another thread I guess charging profiles can deviate so shouldn't be a problem.
 
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Still seems to work incorrecty. As mentioned I have two pandora's charging side by side. One of them doesn't have any problem and is currently full at 100%. After closing the lid for the night is was discharging to appr 88% and then started to charge again until now.

The other (bad) one reached 97% yesterday evening - closed the lid and this morning was discharging at 85% and is still discharging now (69.1%)

I am pretty sure that removing the battery or even removing the power from the Pandora and plug it in again will start the charging process again. That is the behaviour I have noticed before the test. During charging occasionally the charging LED flickers a few times - no charging indication in System Info though. 

I will keep them plugged in until the battery is almost fully discharged and then I will switch batteries to see if this is caused by the battery or Pandora.
 
Do be careful not to plug a battery into a unit that's already connected to external power; that's apparently almost guaranteed to mess up the charging logic.

Are the power consumption figures between the two units comparable? Also, System Info is capable of producing graphs of behaviour, and it might be simpler if you posted those rather than trying to explain the behaviour longhand.
 
Can't compare power consumption right now because one is charging and the other one is discharging. I have set logging enabled for both, might be interesting to compare them after a while - I assume it will take at least one - two days to have gathered enough data. 

I have indeed changed batteries while the power was plugged in especially with this unit. I was swapping batteries continuously.
 
This morning the battery was flat again. Maybe the plots will reveal some information.

I will place this battery in another Pandora and try again. 

plot-charge.png

plot-charge-std.png

plot-cpu.png

plot-mem.png

plot-power.png

plot-power-breakdown.png

plot-temp.png

plot-timeleft.png
 
Hmm, on those first two graphs, it labels the current charge track, but hasn't drawn one. I don't know if that's a bug in system info, a peculiarity of the way it draws the chart, but if the system can't get the current charge level, that would make any charging logic suboptimal.

I'll have to see if I can get an equivalent graph to compare.
 
Thanks Levi, but not needed. See plots from another Pandora and another battery without the charging issue to compare.

plot-charge.png

plot-charge-std.png

plot-cpu.png

plot-mem.png

plot-power.png

plot-power-breakdown.png

plot-temp.png

plot-timeleft.png
 
Okay, there are some small discrepancies in the RAM chart, but perhaps you'd been doing some other stuff on one of them before running systeminfo, or they're not at the same OS version. Shouldn't matter though - you can see it draining the battery, then topping it up over and over on the battery charts.

However, on the battery charts now the red crosses indicating the actual charge are definitely there, and clearly missing on the original charts. I forget exactly where that data's put on the file system /sys/class/bq...something, I think. If you can work out what that folder is, can you see if it has a charge_now file in it at all on both units, and if so, what's in it (should be ascii numbers in there).
 
Changed the battery and the results suggest the battery is not the problem, but the unit is. The other battery was also flat after a night of 'charging'

Difference in RAM can be explained because of the difference in units. The one with the charging issue is a classic unit. So seems like a hardware issue, probably need to contact ED.

Added the latest plots and you can see a similar charging profile - it did charge for the first few hours. 

plot-charge.png

plot-charge-std.png

plot-cpu.png

plot-mem.png

plot-power.png

plot-power-breakdown.png

plot-temp.png

plot-timeleft.png
 
You could check the charger itself of the bad unit, maybe it's faulty and is not providing enough current. It has been reported in the past that some chargers that came with pandoras were no good.
 
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Okay, I tried that once - and thought to see the same behaviour after a few minutes with another adaptor - but lets see how it works if it is plugged in longer than that.

I don't use the original adaptors anymore - all my Pandoras are charged with speedlink psp adaptors. Of course they can have issues as well.
 
Unfortunately changing the adaptor didn't help - battery is flat again. So I think there must be an issue with the unit. It is interesting that after having the unit unplugged and plugging it in charging usually works for quite a while. After reaching appr. 80% is has a risk of stopping charging and when it stops it will only start again after unplugging it.

Does this make any sense?
 
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Not really, probably something is broken like you say.

You could check dmesg on that unit, maybe it logs something there.
 
I have charged the Pandora with mini usb without issues. So I guess I will use that to charge from now on. Not a big deal but it would still be nice to be able to charge with the adaptor. Maybe dmesq reveals something. 
 
Output of dmesg - see attachment
 

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My Battery stops charging even at around 75% and it only starts again when I replug the charger. It was not a cheap one.  Well and the Battery somehow does not go much above 85-90% if the charging indicator displays this correct. I suspect the 1000mAh my charger provides may not be enough for the Pandora battery, however, the (cheapo) stock charger that came with my Pandora also had only 1000mAh.
 
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