Can this battery be recovered?

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mangocats
 
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Can this battery be recovered?

Post by mangocats »

Hopefully wrapping up the saga that started with viewtopic.php?t=194692 , in there I had a pid353 6600mAh 3.7V 3 cell LiIon pack which had a bad time with a 259 charger board that was acting strangely (lights indicating "test mode", among other problems.)

So, that pack currently reads 2.66v. It can drive a 42-60mA load (the Pi Pico + stuff) and holds up around 2.4v while doing so. I have tried plugging it into a new-from-package 259 charger (with no load), but as soon as I apply 5V in to the 259, it flashes an amber light for a tiny fraction of a second, then goes to green light and the BATT terminals of the 259 read 4.25v - sounds like high impedance on the battery to me... unplugging the 5V in to the 259, the BATT terminals return to the 2.66v range, driven by the battery.

What would be the best course to try to recover this 3 cell pack to a more normal voltage range?

It doesn't seem like the 259 is doing much for it, but maybe?

Thanks,

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sj_remington
 
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Re: Can this battery be recovered?

Post by sj_remington »

If the voltage of a single lithium-based cell drops below about 2.6 V, it is generally regarded as destroyed, and not salvageable. If that is the voltage you are measuring for three cell pack, it sounds hopeless.

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mangocats
 
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Re: Can this battery be recovered?

Post by mangocats »

sj_remington wrote: Wed Sep 28, 2022 7:47 pm If the voltage of a single lithium-based cell drops below about 2.6 V, it is generally regarded as destroyed, and not salvageable. If that is the voltage you are measuring for three cell pack, it sounds hopeless.
These are three cells in parallel... I have read a bit about freezing LiIon batteries, but that sounds like a special recovery mode charger is needed after freezing. The main thing I don't know about is the behavior of the protection circuitry in the 353 product.

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mangocats
 
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Re: Can this battery be recovered?

Post by mangocats »

So, on what appears to be functioning like an extreme trickle charge, the 353 battery now reads 2.82v at rest and that number has been consistently climbing 1mV every 2 hours or so for the last 3 days.

The 259 charger supplies the battery with 4.23v when it is powered, but obviously very little of that is reaching the battery, the 259 shows green "Charge Complete".

At this point, I'm assuming it's something in the https://www.adafruit.com/product/353 battery protection circuit that is preventing more current from being delivered when 4.2+v is applied - I have tried disconnecting the battery and leaving it for a couple of minutes before reconnecting - is there anything else that might reset the protection circuitry in the battery pack?

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mangocats
 
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Re: Can this battery be recovered?

Post by mangocats »

October 17th update, 2.902v and climbing, oh so s l o w l y.

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Franklin97355
 
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Re: Can this battery be recovered?

Post by Franklin97355 »

I think the battery is seen as a semi-charged one and the charger is going to trickle charge. If you have an other battery I'd let it alone for a week and then see if it is able to hold a charge being used. There are articles on reviving a lipo but I can't recommend them, you could burst the battery apart or set your house on fire, not pretty.

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mangocats
 
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Re: Can this battery be recovered?

Post by mangocats »

Agreed, LiIon are definitely on my "handle with care" list. I worked with a small drone company and witnessed a 4S pack without protection get dead-shorted one day, it's really impressive how quickly 12 gauge wire can go from room temperature to white hot, and with that kind of energy available you definitely want to play on the safe side of things.

However, with the pack's (as mentioned above, very desirable) "nanny" circuit in place, I was unable to trickle charge the pack voltage above ~2.92V with 4.2V applied by the charging circuit - for weeks.

So, tempting the feline mortality curse, I opened the pack and found that the actual cell voltage is 3.17 when bypassing the protection circuit. I have a reasonably smart and careful LiIon cell charger https://www.amazon.com/gp/product/B07BFWHD7G so I put one liberated cell in it and it is currently accepting the standard 500mA charge current with voltage climbing fairly rapidly - up to 3.45 after 10 minutes and not getting warm in the process.

I wholeheartedly agree that caution is warranted when handling LiIon cells - but it seems in this case that the protection circuit is maybe a little over-zealous in its protection of the cells from incoming charge energy.

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mangocats
 
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Re: Can this battery be recovered?

Post by mangocats »

5 hours on the 500mA charger and all 3 cells seem to be back to full functioning. I don't have a test system to see what their capacity is now, but they definitely are usable.

Question: is there a smart charger that can "work through" the protection circuitry to recover cells in the state these were in?

The protection circuitry did let them over discharge to a point where the 4.2v limited charger wouldn't bring them back (couldn't deliver any current to the cells that were sitting at 3.17v). Without the protection circuitry in the loop, the 500mA charger started at 3.17v and worked up to 4.22v in just about the time expected for a 2200mAh capacity cell.


Last bumped by mangocats on Thu Dec 01, 2022 3:27 pm.

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