Li -ion battery


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Revlac

Guru

Joined: 31/12/2016
Location: Australia
Posts: 459
Posted: 08:50am 05 Apr 2021      

Before attempting to charge this pack I wrapped up the back end with some masking tape to help hold it together.
I tried charging the one that has the black plastic wrap removed, I set the charger to 6v then connected it up turned the charger on and it maxed out at 40Amp for 3 seconds the dropped back. I then gradually increased the voltage as the amps dropped, after about 10 minuets I reached 12v on that pack.

Turned it off and disconnected over night, checked the voltage the next morning and the battery was dead flat, Did the same cycle again the next day  and the battery started to hold a little charge of about 1.5v.

Did the same cycle again, this time it was holding over 6v, looks encouraging.
Will do this with the other packs.

These are Lifepo4 pouch cells, LFP.
What We think has happened with this Flatpack is that it was left sitting flat (Discharged) for a long time.
An overcharged cell that has swollen up would not flatten out with any recharge.



Now in the photo you can see the masking tape is really slack, what is most surprising is the cells (while charging and left for some time) have sucked back down flat most of the way, was expecting that.



While charging this pack I did check every cell often to make sure none of then where going over voltage, it was nice to see all cells in this group where charging and voltage was equal on each cell.

Will have to peel open the cover on the end of the other 2 packs to check the while charging, see if they do the same thing, there is a small chance that they might might all charge up and work, will take some time to go through this process, but definitely worth trying.
Thanks Bruce for letting Me work on this.
Can't say for certain that all this will work, too early to tell, there is also the issue of high resistance that could make the battery difficult to use, will wait and see what happens...