Bizarre charging behaviour


antisol

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Hi

My pandora is doing some really weird stuff WRT charging. I've managed to convince myself that it's probably some kind of software issue.

My pandora's usual resting spot when not in use or in my pocket is sitting on my coffee table, plugged into its charger, screen open but turned off (power management). In normal operation for the past ~5 years I can expect to see it with the red "charging" light either on or off - it switches on every couple of hours, charges for a little while, and then switches off for a couple of hours and lets the battery drop. Sometimes the battery will drop to ~85% or so but this is pretty rare. Usually it's at >90% when I pick it up to use it or to take it somewhere.

Recently (maybe 2 weeks ago) I saw the charging light flash to indicate that the battery was critically low. It had been maybe a week since I used it or did anything to it. I'm not sure.

I picked it up and investigated and was unable to get it to charge using the charger. When I plug it in, the charging light will light up red for less than one second and then the battery will continue to discharge.

I tried rebooting, this had no effect.

I tried updating the OS. I had to free up some space on the internal storage to do that because when I first tried I was told I didn't have enough space. Once I did that, running "upgrade pandora OS" didn't update any packages.-'

I have a second wall charger (which has only been used maybe half a dozen times in 5+ years). I tried that. It behaves the same way.

I put a multimeter on the wall charger plug. The voltage I get fluctuates occasionally but stays between 5.25-5.26VDC.

Eventually I was able to get it to charge by plugging in a mini usb cable. This seemed to work OK so I figured that the charger plug on the pandora had probably developed an issue. I don't think I've used the pandora for anything since then, though I have unplugged it, taken it out somewhere, and then plugged it back in when I got home.

Last night, I noticed the charging light flashing again to indicate that the pandora had a critically low battery.

I unplugged it and plugged it back in and the charge light came on for less than 1 second and then turned back off.

I did this a couple of times and eventually it started charging. I fired up the system information program and switched it to the battery tab so that I could keep an eye on it. The battery seemed to be charging, saying 7 hours (or something, I don't remember exactly) until full. I left it alone.

I just noticed this morning that the battery monitor was reporting something strange:
"Time left till full charge: ???"
"Percent full: ~110%" (i forget the exact figure)
"Percent of design capacity: ~102%"
"Charge: >4200mAh and rising"

I disconnected the USB cable and lef the battery discharge a little bit, then I plugged it back in (it was still over 100%). it immediately started charging again.

I am now worried about leaving it plugged into the USB charger because I don't want to damage the battery or the pandora, but at the same time I want to leave it plugged in so that it's always close to full when I want to take it somewhere.

I'm also pretty worried that maybe I'll find myself in a situation where I'll be unable to charge the pandora at all. this will obviously make the device totally unusable. That would be bad.

Ideally, I'd like to get things back to normal operation.

I'm not sure what else I can try to figure out what's going on, or what I should do to? Had anybody had any similar experience? I searched the forums briefly but it seems like other people having issues with charging are related to a bad connector or cable. I don't (anymore) think that this is the case here. If there's a test I can do to find out more definitively, I'd love to hear about it.

Can anybody give me any advice? If there's any more info you'd like or any clarification I can give on any point, please just ask and I'll be happy to reply.

Thanks!
 

PowerGod

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Try a "sudo dmesg" from a terminal, and have a look if there are high temperature warnings.
 
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antisol

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Thanks.
I don't see any temp warnings at the moment. Is there a particular time I should be looking - when the system is idle? charging? not charging? >100% charge?

I *DO*, however, see a few ubifs errors. That's the rootfs, right? A corrupted OS could cause all kinds of weirdness. Is there a fsck type tool I can use to run a scan on the internal storage? How can I run that scan with the disk mounted? (on a PC I'd insert a livecd, not really an option here as far as I know?). Is there a way for me to take a ddrescue-type image of the rootfs?
 

rSl

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until it's clear what's going on, i would suggest not to let your pandora charging unattended, just to be on the safe side.
 

FBnil

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Take out the battery for 5 minutes. Put it back in. The Pandora has charging hardware, and maybe that developed a bug. By disconnecting it a while, it might reset.
105% charged means the charging software finds the battery better than expected/calculated when going into trickle-charge, and keeps charging it until it "feels" the battery can take no more.

And yes, the mini USB is fickle sometimes, you need to re-plug it for it to detect that it is charging (doesnt always need to be at the Pandora's end).

Also, take out the battery, and while putting all sides on a flat surface, see if it started bending. If so, you might need a new one (or extra paper/elastics to keep it in place)
Post automatically merged:

I don't see any temp warnings at the moment. Is there a particular time I should be looking - when the system is idle? charging? not charging? >100% charge?
While charging, just put your hand underneath the device and feel the temperature. If very hot, it automatically slows the charging. put it on a wet towel, that dissipates the heat fast.
Keeping the Pandora clamshell open also helps a bit with cooling.
 
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antisol

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Thanks for the tips everybody. Apologies for my slow reply.

reflash it.
Ouch. That's a lot of work. I'd rather debug it. As a last resort, sure, but I'm not inclined to just jump straight to that.
i would suggest not to let your pandora charging unattended, just to be on the safe side.
Way ahead of you on that. But thanks :)

Take out the battery for 5 minutes. Put it back in.
I just did this and something odd happened: When I put the battery back in, the system is reporting about 5% charge. It was at about 85% before I took the battery out.

It's at 6% and charging from USB now. I'll report back on how that goes.

I also tried the wall charger and saw the same thing described above - the charging light came on for less than 1 second

see if it started bending
If it's bending, it's only by about 1mm. But I think that it's just raised up because it has the raised area for the battery contacts.

put your hand underneath the device and feel the temperature
I haven't noticed it being warm, but I'll keep an eye on it.
Keeping the Pandora clamshell open also helps a bit with cooling
It's spent most of its life open - the "standard rest position" on the coffee table is open.
 

antisol

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More weirdness.

While charging, just put your hand underneath the device and feel the temperature.
OK, it's back up to a full charge. I checked once while charging and then again when the battery was at 102% (92% of design) and still charging.
Not even warm. No temperature warnings in dmesg.

BUT, I do see this:
Code:
[   67.757598] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (5), disabling charger
[   68.000091] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (7), disabling charger
[   68.175628] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (9), disabling charger
[   69.935333] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (11), disabling charger
[   86.343963] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (5), disabling charger
[   87.954956] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (5), disabling charger
[   89.738739] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (7), disabling charger
[   89.854431] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (9), disabling charger
[   89.925903] twl4030_bci twl4030_bci: spurious CHG_PRES irqs detected (11), disabling charger

I also had another weird thing just happen: I was sshing into another machine to copy-paste the message above to my laptop so that I could paste it here, and the screen turned off! I absolutely did not press anything that would cause that. I was able to turn it back on using the brightness controls, and it might be unrelated, but that's just weird. I'm now more tempted to try reflashing, if nobody else has any suggestions?

Also, after doing the above it has dropped from 102% to 100.6%, even though the charge light stayed on the whole time and sysinfo says it's still charging.
 

antisol

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Well I feel stupid. for some reason it's only just now occurred to me to try my spare battery! duh!

It's at 88% (impressive, given that it's been about 3 years since I used it) and discharging. I'll let you know how it behaves.
 

FBnil

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Also, after doing the above it has dropped from 102% to 100.6%, even though the charge light stayed on the whole time and sysinfo says it's still charging.
It is possible to drain the battery faster than it can charge if you enable the USB port, for example. I have some highspeed USB sticks that, combined with VLC decoding video from them, eat more than can be charged.

Also give us the settings (with the old/bad battery) as stated here, when doing another battery calibration:


The screen can blank if you do not touch the interface (touchscreen, mouse, keyboard) for a while. That's an XFCE Linux configuration. If you do not like it, there are 2 places where you can/must change it:

Menu/Settings/Video-Settings
Menu/Settings/Desktop/XFCE 4 Power Manager

It's at 88% (impressive, given that it's been about 3 years since I used it) and discharging. I'll let you know how it behaves.
It's best to store them within 80% to 60% (i.e. It's not good to store them with 100% charge

I just did this and something odd happened: When I put the battery back in, the system is reporting about 5% charge. It was at about 85% before I took the battery out.
Ouch, you short-cirquited your battery while putting it in. Also can happen when you drop your Pandora. Happened to me many times. It did not kill my battery, but I had to re-charge it again.
Post automatically merged:

I'm at 1038 charges, and full = 91% of design
 
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antisol

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The screen can blank if you do not touch the interface (touchscreen, mouse, keyboard) for a while. That's an XFCE Linux configuration
Oh, sorry if I wasn't clear about exactly what happened: the screen blanked while i was typing on the pandora: i was ssh'd into my laptop from the pandora. Pressing a key or touching the screen didn't bring it back as I'd expect - I had to use the brightness keys. Also I'm running openbox, not xfce.

I'm about to go to bed. I'll do the battery calibration stuff tomorrow and get back to you. Thanks.
 
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levi

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It's also worth checking your cable. I assume you've got a multimeter in your hobby box, strip some sort wires and wire up the barrel plug and check the voltage. But, providing the cable hasn't degraded, I think you'll end up at my first answer in the end ;)
 

antisol

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give us the settings (with the old/bad battery) as stated here, when doing another battery calibration
OK, I'm working on the battery calibration now. I'm getting close to 100% charged, but I'm unclear about this instruction from the wiki page you linked to:
and "cat /sys/class/power_supply/bq27500-0/current_now" reads around 800000. If the meter reads 100%, make sure to check these two files to ensure it's actually FULL. Realistically a charge current below 100000 is close enough.

It seems to me that these two numbers are inconsistent. Probably a typo? Should it be 80000 rather than 800000, or 1000000 rather than 100000?

Currently I'm at 95% and seeing:
Code:
~ $ cat /sys/class/power_supply/bq27500-0/voltage_now
4168000

~ $ cat /sys/class/power_supply/bq27500-0/current_now
267000

and the 267000 number doesn't seem to match either of those?

I'm at 1038 charges, and full = 91% of design
Where did you find the number of charges? I don't see it on that page?
Full is 90.77% of design for me according to sysinfo.

hmm... that's weird indeed.
I know right. If I was you, I probably wouldn't believe me. I'd be asking things like "are you sure that you didn't accidentally hit the brightness key? And you didn't imagine it?". But I promise it did happen ;)
Might not be relevant. Just another weird thing in addition to other weird stuff so I thought I'd mention it.


It's also worth checking your cable
Covered in my first post.
 

antisol

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It seems to me that these two numbers are inconsistent. Probably a typo? Should it be 80000 rather than 800000, or 1000000 rather than 100000?

OK, after keeping an eye on these numbers I'm able to answer my own question: the current is slowly dropping and will likely get to below 100000 pretty soon (currently at 150000 and charge is at 100.4%). it's meant to be 100000

800000 is a typo. If someone has an account on the wiki maybe you could fix this? (i'd rather not sign up just to fix that one thing)
Post automatically merged:

200722-202536.png
 

antisol

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OK, battery is fully charged. It didn't make it all the way down to 80000 because it stopped charging, but it got pretty close. I had a script checking the values every 20 seconds:
Code:
Wed Jul 22 20:53:20 EST 2020

$ cat /sys/class/power_supply/bq27500-0/voltage_now
4198000

$ cat /sys/class/power_supply/bq27500-0/current_now
84000

Wed Jul 22 20:53:40 EST 2020

$ cat /sys/class/power_supply/bq27500-0/voltage_now
4149000

$ cat /sys/class/power_supply/bq27500-0/current_now
-342000

I've just taken the battery out and will leave it for 5 hours per the instructions.
 

antisol

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Battery is now discharging. When I put it back in it said it was at 90%

200723-025902.png


Code:
$ cat /sys/class/power_supply/bq27500-0/capacity
89

$ cat /sys/class/power_supply/bq27500-0/present
1

$ cat /sys/class/power_supply/bq27500-0/status
Discharging

$ cat /sys/class/power_supply/bq27500-0/temp
168

$ cat /sys/class/power_supply/bq27500-0/time_to_empty_avg
34080

$ cat /sys/class/power_supply/bq27500-0/time_to_empty_now
36840

$ cat /sys/class/power_supply/bq27500-0/time_to_full_now
cat: /sys/class/power_supply/bq27500-0/time_to_full_now: No data available

$ cat /sys/class/power_supply/bq27500-0/type
Battery

$ cat /sys/class/power_supply/bq27500-0/uevent
POWER_SUPPLY_NAME=bq27500-0
POWER_SUPPLY_STATUS=Discharging
POWER_SUPPLY_PRESENT=1
POWER_SUPPLY_VOLTAGE_NOW=4119000
POWER_SUPPLY_CURRENT_NOW=-304000
POWER_SUPPLY_CAPACITY=89
POWER_SUPPLY_CAPACITY_LEVEL=Normal
POWER_SUPPLY_TEMP=168
POWER_SUPPLY_TIME_TO_EMPTY_NOW=36840
POWER_SUPPLY_TIME_TO_EMPTY_AVG=34080
POWER_SUPPLY_TECHNOLOGY=Li-ion
POWER_SUPPLY_CHARGE_FULL=3847000
POWER_SUPPLY_CHARGE_NOW=3460000
POWER_SUPPLY_CHARGE_FULL_DESIGN=4240000
POWER_SUPPLY_CYCLE_COUNT=767
POWER_SUPPLY_ENERGY_NOW=12800000

$ cat /sys/class/power_supply/bq27500-0/voltage_now
4119000

$ cat /sys/class/power_supply/bq27500-0/current_now
-304000
 

FBnil

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@antisol I think the information is not visible because you have the bar always on top, and the maximixed window is behind it, try to resize the window, like in the image. See the bottom right of the application window. It could also be you have an older version of the Pandora System Info, latest is: http://repo.openpandora.org/?page=detail&app=sysinfo.wb
pandora_systeminfo_battery.jpg
 

levi

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I've just taken the battery out and will leave it for 5 hours per the instructions.
Good stuff. Make sure you don't have the system on/on charge (it's the same thing when it comes to pandoras without batteries) when you put the battery in. There's a historic warning against doing that, and while I've never heard of it causing any damage, it did caveat against confusing the charge chip by hot swapping batteries.
 
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