LiFePo4 replace just one cell?

[wallypedal]

We have an older LiFePO4 battery, 12 cell 36v, came in an aluminum case. Although 5 years old or so, there were not many charging cycles at all on it. I'm a long way from being a battery expert, just know what I've read here on ES. This battery has a bad cell. All the others are in the 3.5 to 3.6 range, this one is shot. With the charger hooked up, it will try to go to 1.1 v or so, this with the BMS disconnected. The charger will kick off at about 43 v, but available volts will drop back to 36 to 37 or so if left unplugged for long. Then the bad cell reads almost zero. The BMS was suspect and so it isn't wired in right now.
Can these individual cells be sourced and replaced? Is there a place to get them? Are replacement BMS's available stand alone that can be hooked up easily? It looks like the connectors are common. The cell is rectangular, maybe 3/4" thick, 3" wide, 6" long, approx. I can post pics of the cell and BMS if that would help anyone advise us.
Thanks! Wallypedal

 

[dogman dan]

The main problem will be finding the replacement cell in the same shape and capacity.

But before you go to that much effort, I'd suggest doing some kind of capacity test of the remaining cells. If they hold a charge, but have very low capacity, it might not be worth the effort.

You can do capacity test on one cell at a time with an RC charger, or the whole pack with a cheap blue wattmeter from ebay.