280ah bad cell

[schmism]

One of the cells in my 280ah china cell pack has finally failed. I noticed my pack capacity seemed to have been dropping and with the recent power outage i actually took the pack down to cut off voltage which hasnt been done since the first week it went into operation. As we have full sun to day ive been monitoring the pack as its been charging and it didnt seem right. quick check in the basement led to an odd smell and some bulging cells. So i pulled the pack off the system.

Options, tear down the pack and test each cell finding bad ones and replace the cells?
Tear down the pack ,find bad cells, recycle them and sell off the others as used and replace with? EG4 server rack?

as an aside my NMC leaf cells are still holding up fine.

 

[timselectric]

Do you think that they were originally bad?
Or do you think that you pushed them too hard?

 

[robbob2112]

More quesion -

Have you checked the bus bar/cell connections to see that none are hot or any signs of corrosion?

 

[schmism]

Do you think that they were originally bad?
Or do you think that you pushed them too hard?

I think it had a manufacturing defect that was the cause of the issue.

More quesion -

Have you checked the bus bar/cell connections to see that none are hot or any signs of corrosion?

I just got done disassembling the pack to the point that I removed the bad cell to take it outside. All the connections I removed were clean and tight.

 

[740GLE]

Is this a DIY battery?

What BMS were you using?

 

[timselectric]

I think it had a manufacturing defect that was the cause of the issue.

Still under warranty?

 

[schmism]

Warranty is only as good as the person who is going to back it and given who I sourced the cells from, that is unlikely.

The price at the time was reflective of that.