12s losing a cell?

[2easy]

Gents,
Been running a 12 s setup, 26s x 5000 mah and im loosing a cell in one bat. Happened to me once already and im gonna try the trickle in NiCad instead of lipo to get the cell back, but now I have noticed the same thing happening in another brand new pack. Coincidence or is it something in my esc....120hv by the way. Thoughts?

[DrSteve]

Is it the same cell in both instances? Can you confirm the cell voltages after charging on another device? Maybe the charger is out of calibration on that cell.

Are you balance changing every time? This is recommended.

What are the voltages of the packs/cells after you finish a flight? Are you using more than 80%?

[2easy]

Yes on the same cell

Yes balance charging always

Cells at 3.86 per after a flight. After a few flights it wont allow the charge in that cell to exceed 4.0 when charging. If I keep using that battery it will drop off past 3.2 and be unrecognizable by the charger....0 Maybe its my charger that's going but I run other packs through it and they charge to 4.20 per.

[2easy]

correction different cells...number 6 and now number 2

[P@reez]

Are your balance leads / main charging leads soldered in well? I recently had an issue where cell #1 on my 6s pack would sometimes show higher IR and would also have trouble charging completely to 4.2v. After a few days, while hooking up the charger, the positive lead came undone from the EC5 connector. I replaced it with another wiring harness and the cell #1 IR is back to normal and it charges fine.

[2easy]

Originally Posted by P@reez

Are your balance leads / main charging leads soldered in well? I recently had an issue where cell #1 on my 6s pack would sometimes show higher IR and would also have trouble charging completely to 4.2v. After a few days, while hooking up the charger, the positive lead came undone from the EC5 connector. I replaced it with another wiring harness and the cell #1 IR is back to normal and it charges fine.

Hmmm...ill check that. I have taken apart the first battery tracing the balance lead wires back to each cell just to make sure they are all connected and they are. When you check each cell through the balance lead with a volt meter they move up in 4.2 v increments until you hit the "dead" cell and it carries the total volt sum from the previous cells, not adding an additional 4.2 v.

[2easy]

Could it be coincidence that these cells have just died??