so i have a 48v battery bank with 16 3.2volt 280 amp hour cells. one time before cell #11 died before the other cells and would also charge faster than the rest so i changed it. everything was fine for a while until it started happening again. i changed in out again with another new cell. i ended up with the same problem. even if i move the bad cell amongst the bank cell #11 still dies. its almost as if its not the cell itself but the cell placement in the #11 spot. could this be a bad bms?
cell number 11 keeps dying ?
- Thread starter Mikep876
- Start date
sunshine_eggo
Happy Breffast!
I can't think of a situation where a BMS could cause a cell to die in the manner and with the symptoms you describe except for maybe a malfunction in an active balancer. Especially if the problem moves with the cell.
See line #2 in my signature.
Did you top balance the battery when you replaced the cell?
Cell sources?
History of battery?
BMS brand?
See line #2 in my signature.
Did you top balance the battery when you replaced the cell?
Cell sources?
History of battery?
BMS brand?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Oh God.... you hit the 11th dimension portal!!! It's sucking energy out of our mere 3 dimensions!!!! It could suck the life out of anyone standing too close!!!
In all seriousnous, if it is always the 11th cell, it has to be either the wiring to the cell or the BMS. Those are the only things I can think of that would stay at the 11th cell position. I can't see how the wiring could be doing what you describe so I suspect the BMS.
In all seriousnous, if it is always the 11th cell, it has to be either the wiring to the cell or the BMS. Those are the only things I can think of that would stay at the 11th cell position. I can't see how the wiring could be doing what you describe so I suspect the BMS.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Good point about balancing!! If the cells are not balanced when one gets swapped in, there could be issues. However, if I follow his saga correctly, he can move the cells but the issue remains at cell 11. This would indicate it is not a cell balance issue.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
That would be an easy test, check the cell in Position 11 with a Multimeter and if it matches the BMS reading, then it's not the BMS. In fact, a BMS will not affect cells charging, it can't do that. The only thing that "could" happen, is that it misreads & misreports it OR if the BMS has some sort of balancing, that won't be applied to that one cell.
Have you swapped the busbars out for Cell 11 ?
Make sure the contacts are clean with no burrs or ridges on the busbars and that they are properly tightened.
Have you swapped the busbars out for Cell 11 ?
Make sure the contacts are clean with no burrs or ridges on the busbars and that they are properly tightened.
sunshine_eggo
Happy Breffast!
hwy17
Anti-Solar Enthusiast
Bad crimp on 11's balance wire ring terminal or BMS 11 passive balancer is stuck on.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I guess it could be a bad crimp on the balance wire if it is an active ballence system, but the currents on a passive system are so low that it seems unlikely the crimp is resistive enough to be an issue without being an out-right open circuit.
Now that active balancing has come up, is there an active balancer parallel to the BMS? Is it wire correctly?
i did top balance when is build the battery but not since then. checked all the connections but will check again. currently i have an overkill solar bms and eve cells. as of now im running the bus bars to the terminals first and the bms leads on top of the bus bars. I've had this battery for roughly 3 years and i cycle it every day.
MisterSandals
Participation Medalist
Can you post a pic of your battery wiring?
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As an aside, i recommend labeling/naming your cells with letters (A, B, C...) to avoid any confusion with the cell position which of course is a number (where cell 1 is the negative end of the battery).
sunshine_eggo
Happy Breffast!
As-received cells are typically 30-50% SoC. Did your battery and cell SoC match when installed?
