Is my battery in need of replacement?

[Exophase]

Although 5% for 15 minutes still seems like a little much. That would mean I'd get about 5 hours game time, and my Pandora definately lasted longer than that before. But I guess that's just natural battery degredation over time?

Disregarding the wrong percentage, this methodology isn't really correct.. voltage vs capacity on Lithium Polymer batteries is very non-linear. See the graphs on this page:


http://www.ibt-power...um-Po-tech.html


Capacity vs time, on the other hand, should be a lot closer to linear, at least away from the extremes, since you'd be drawing about the same power. There'd probably still be some second order effects as the efficiency of the power regulators might change slightly depending on how close the input voltage is to their output voltages, but I wouldn't expect it to vary nearly as much and certainly not in a way that cancels out the voltage vs capacity non-linearity. In other words, you shouldn't look at voltage drop between two points and try to linearly extrapolate what your battery life will be.

This could be a useful tool to monitor what your battery is reporting:


http://boards.openpa...ra-system-info/

Maybe you could add a logging feature so we can see the aforementioned curves

 

[Barnaby]

Just thought I'd come and give an update on my battery - after leaving it for an hour after fully chargiing it and turning it back on, it had dropped to 90%. 10% was roughly the amount is had mis-calculated before (when it was at 11% then went straight to 0%) so I thought it had something to do with that. Been using it a little and it seems to be OK. Maybe dischargining slightly faster in sleep mode than before, but there doesn't seem to be any issue anymore. I'll keep using it and see what happens near 10% again. If issues persist I'll download that app that _wb_ linked to which looks pretty useful.


Thanks everyone for your help, especially WizardStan! The information you provided was super useful and I hope other people with issues will find this thread.

 

[SNESFAN]

This could be a useful tool to monitor what your battery is reporting:


http://boards.openpa...ra-system-info/

wow that's really great, I'm going to check it out, this could be really useful especially if it's information it highlights could be incorporated into a status bar "widget" of sorts.

 

[WizardStan]

I'm a fairly novice programmer but I would like to help fix this if it's not already being worked on. Can you point out the applicable files that control this on the xfce side of the house?

There's no application to be rewritten. It's handled entirely in the hardware of the BQ chip, all the GUI does is ask the chip for the value and then displays it. It does so by constantly monitoring the current_now value and tracking how much power can go into the battery and how much comes out of it. current_now is the measure of the current being used right at that instant. The variables you're looking for are "charge_full" and "charge_now". These are both populated automatically by the BQ chip and yield the percentage remaining. There is no way we can make something more accurate in software.


Hmmm...


When it reaches 100% and is still charging, do a


cat /sys/class/power_supply/bq27500-0/charge_now


cat /sys/class/power_supply/bq27500-0/charge_full


You'll probably be able to watch as charge_now starts to exceed charge_full. When it reaches full charge and you turn the Pandora off for an hour this is supposed to be the signal to the chip that this charge_now value is the new charge_full.

 

[SNESFAN]

There's no application to be rewritten. It's handled entirely in the hardware of the BQ chip, all the GUI does is ask the chip for the value and then displays it. It does so by constantly monitoring the current_now value and tracking how much power can go into the battery and how much comes out of it. current_now is the measure of the current being used right at that instant. The variables you're looking for are "charge_full" and "charge_now". These are both populated automatically by the BQ chip and yield the percentage remaining. There is no way we can make something more accurate in software.


Hmmm...


When it reaches 100% and is still charging, do a


cat /sys/class/power_supply/bq27500-0/charge_now


cat /sys/class/power_supply/bq27500-0/charge_full


You'll probably be able to watch as charge_now starts to exceed charge_full. When it reaches full charge and you turn the Pandora off for an hour this is supposed to be the signal to the chip that this charge_now value is the new charge_full.

I guess I wrote that whole thing for nothing, I kind of see what it's doing now


I did let it sit for an hour at full charge, and it did track the 100% mark for a bit and once I unplugged it it went right to 99% the problem is, the setting didn't "stick" I guess. On recharge it reverted.


Does removing the battery reset it?

 

[WizardStan]

It should maintain it indefinitely, it has it's only PROM. You can also check the cycle_count file. A complete cycle is discharging it to 0, leaving it off for five hours, then charging it completely and leaving it off for an hour. Or the other way around, charging and then discharging, I forget exactly now (secretly that's why I say it may need to be done twice ). Either way, if you're trying to force the gauge to remember, make sure that this number increases. If it didn't increase then it didn't record the change and you should try again.


I only just noticed that the cycle_count file exists else I'd have mentioned it sooner. It wasn't there before, pre-SuperZaxxon. I used to do some custom hackering to get the value out of the chip before, but this makes it so much easier.

 

[meandu229]

Im having wierd issues that I think are to do with the battery im not sure, basically about 50% of the time my pandora wont turn on, or at least the screen doesnt turn on the green LED turns on and sometimes the SD card LEDs flicker indicating its trying to boot or something, but the thing just wont turn . as soon as I try to turn it on with power plugged in it boots fine and I can unplug the power straight after I see the pandora logo. After boot my battery is fine e.g its currently at 92%. im just running pcsx with crash banicoot running the intro bit over and over while im at work to run the battery down and going to try to follow the steps in this thread. Any other ideas about why this would happen?


P.S mine is also back from RMA and been a while since it has been used and battery has just been sat in a box on my desk for over a month.

 

[meandu229]

Just FYI fixed my issue, the lcd cable wasnt plugged in properly, it seems that when I was pushing in the power cable i was also pushing the lcd cable as they are close together,, all sorted now

 

[Barnaby]

Would a mod be kind enough to label this as [sOLVED]? My battery seems to be working fine now, it's definately not as bad as it was at any rate. It's charging and discharging normally now