Pepin wrote:I think so. But maybe the cell it´s ok and the read it´s the problem . Because we can see the voltage for the LTC job and has memory marking a bad cells. . Did you test the bad cells out of the battery after replace?
I tested their capacity after removal yes, and they were much lower than other cells. Testing the internal resistance of the cells is very hard to do on the bench and not possible with simple equipment as a good cell has a resistance of about 1.5 milliohms, so has to be tested at very high current. (Full acceleration in the car is about 150 amps)
LTC faults usually either cause the reported voltage to be intermittently low, always low or zero/infinite. This is why I suggested testing both the excessive voltage drop under load and the excessive voltage rise during rapid charging - a faulty LTC chip would not duplicate both conditions.
It´s a lot of work to open the battery pack. Changing the two elements is possible to save time. The cost of LTC and a cell is cheap.
This is true, but replacing the LTC chip is not an easy job either, and there are some risks.
If you replace the entire CMU board you either have to make sure you have the right numbered board for the location, or access to the dealer diagnostic tool (MUT III or Diagbox) to initiate a renumbering of the CMU boards - and so far we only have one report of successful CMU renumbering.
If you just replace the LTC chip there is a risk of damage to the board if not done very carefully and you could end up causing a perfectly working board to be damaged for no reason.
If I was in your situation and you are not in a huge hurry I would remove and disassemble the battery pack, measure the voltage of cell 69 and another adjacent cell in the same module - if the voltage matches what Canion is reporting (bad cell much lower than others) then its likely the CMU is OK. I would then do a discharge capacity test of the bad cell and a good cell to compare them. If this also shows much lower capacity than the good cell I would only replace the cell.
If the good and "bad" cells both measure the same and pass a capacity test, then I would go to the trouble of repairing or replacing the CMU board.