1 bad module in 14S and how to remedy ?

[carpetpaul]

I'e assembled a 14S pack over the last 18 months or so, having checked really as carefully as I possibly could, charged, tested, waited, re-tested, randomised, and carefully built each of these 100P modules, with the help of RePackr, I find that I have issues with one particular module, which just likes to lose voltage, it recently managed to dive down to 2.5v, which is hardly a healthy state.

I have another 600 cells, which I've tested and am just storing, awaiting a re-test, but I'd really like to get my head around what's going on with this faulty one.

I know that in the past, it will just simply discharge while sat idle

apart from disassembling the whole thing and doing charge / storage test, and looking at the cells individually, since there must be some heating up, what else can I do to weed out the bad apples ?

I've build that pack in the plastic holders, four cells wide, and used twisted copper bus bars for connection, I thought about literally cutting the bus bars to seperate this pack into small sections, see if I can work out which areas of the pack are causing the issue ?

if anyone can help or advise, please reply.

 

[Oleksii]

Give the pack rest for 1 day without charging/discharging.
Disassembly a positive or negative side only and measure voltage on cells after 1 hour or one day. You will find the self dischargers very quickly.

 

[carpetpaul]

thank you for your reply, I'll give this a go, then I'll report back