diy solar

diy solar

Lifepo4 Fault Diagnosis Help Please.....

Nigel Snook

New Member
Joined
Nov 18, 2020
Messages
26
I'm after a bit of help in unraveling symptoms of my installation. My configuration is: 2 in parallel 4S 277Ah ETC Cells (top balanced before assembly) each with Chargery 8T BMS and Chargery DCC in a separate port configuration. Most of time the pack is lightly loaded with short periods of high consumption whilst using inverter (up to 200A) so it is usually operating at fairly high charge. To exercise the pack a little, I disabled all charge sources and applied a load of circa 110A, eventually each of the BMS triggered (at different times) a load disconnect on cell differential which I set to 200mV. Each of the batteries had discharged approximately 75Ah (both measured and calculated) at the trip. SOC at start circa 80%.
Cell voltage at start - all between 3.31 and 3.32V
Cell voltage at trip - High 3.191, Low 2.920, other 2, 3.188 and 3.126. Voltages verified with a voltmeter.

The low cell drops off very quickly, up to that point all cells remained very close telling me that it has simply run out of juice. I realise that a cell shuffle will provide some extra clues but not in a position to do that at present. Do people think it is just a dodgy cell or could there be something else that I am missing?
 
I'm after a bit of help in unraveling symptoms of my installation. My configuration is: 2 in parallel 4S 277Ah ETC Cells (top balanced before assembly) each with Chargery 8T BMS and Chargery DCC in a separate port configuration. Most of time the pack is lightly loaded with short periods of high consumption whilst using inverter (up to 200A) so it is usually operating at fairly high charge. To exercise the pack a little, I disabled all charge sources and applied a load of circa 110A, eventually each of the BMS triggered (at different times) a load disconnect on cell differential which I set to 200mV. Each of the batteries had discharged approximately 75Ah (both measured and calculated) at the trip. SOC at start circa 80%.
Cell voltage at start - all between 3.31 and 3.32V
Cell voltage at trip - High 3.191, Low 2.920, other 2, 3.188 and 3.126. Voltages verified with a voltmeter.

The low cell drops off very quickly, up to that point all cells remained very close telling me that it has simply run out of juice. I realise that a cell shuffle will provide some extra clues but not in a position to do that at present. Do people think it is just a dodgy cell or could there be something else that I am missing?

All connection checked when test run? There is nothing hot ?
Then this is the 2nd ETC weak cell I read here in a weak (that had only 227Ah capacity from the 270Ah even in slow discharge)
 
All connection checked when test run? There is nothing hot ?
Then this is the 2nd ETC weak cell I read here in a weak (that had only 227Ah capacity from the 270Ah even in slow discharge)
All connections checked, I suspect mine is less than 227……..
 
All connection checked when test run? There is nothing hot ?
Then this is the 2nd ETC weak cell I read here in a weak (that had only 227Ah capacity from the 270Ah even in slow discharge)
Hi - could you link the other failed ETC cell please. I’d like to compare notes……
 
Back
Top