Overdischarged cell of a lipo pack

Hello everyone. Today I faced the problem that I hoped I will never face. Overdischarge.

This morning I went to the fridge to get out my lipos for my board from there. I am using 4x 3s 5Ah lipos from HRB to be specific. Then i decided to check all of the voltages and faced the problem: the 4th pack’s 3rd cell voltage was at 1.36V. In other words, it was dead.

I managed to restore it using the IMAX b6 in NiCd mode at 0.1A. Well, I know that it is dangerous as f…k, but I’ve did it anyway.

So now I actually dont know what to do:

-1: I can try to use it in my old setup 6s2p (with one half-dead cell) at my own risk

-2: I can replace this cell just by buying single cell from the HRB. (but it will have higher capacity, which is not good either)

-3. I can desolder this cell as well as one good cell and build my own 10s lipo pack.

-4. I can swap to the absolutely new li-Ion pack but this is an overkill IMO.

So what do you guys think? What should I do?

It happened to me a couple of times with HRB…I restored them, and being checking how they behave…This was 1 year ago and they keep pulling…I just check them every time I charge them (IR), and individual cel voltage before charging…everything with my bms lipo charger…Not paranoid about it…

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Hi, Santino

It seemes like this cell also has significant self-discharge current. Yesterday it was at 3.81v, today it is at 3.77v.

If you do not trust the cell, better to replace the whole pack then… Unless you know what you are doing about desoldering a Lipo pack, I will discourage doing so. But if your are willing to take the risk, I’ll suggest you to do it out side your home, safe from fire hazard, and if something happen, just let it burn (you could throw 10 kilos of sand over it if you have). Other than that, buy new packs, better brand (like Turnigy Graphene), or swipe to Lion. In that case, discharge completely the Lipo and dispose them under your current disposal laws.