not charging my iON, cell or CMU or BMU problems

[Pepin]

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?

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.

 

[DBMandrake]

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.

 

[Pepin]

Thank you. DBMandrake. I will test the cell before to touch CMU. My idea was repair the pack with full charge. I cant't see the difference voltage
if the battery it's fully charged . Then I must go to a low level and the cell of replace with average charge of the rest of package.

With the change of your cells how many Ah, you recovered?.

 

[DBMandrake]

Not as much as I hoped unfortunately.

Ah capacity after doing a recalibration only went up from 32Ah to 34.5Ah, and after about 9 months use it had dropped to 32.5Ah again. This is because while I replaced the worst cells there were other cells which were not quite as bad which now become the worst cells and limit performance.

However the high internal resistance problem was fixed and rapid charging speeds remained good until I sold the car.

In your case it looks like you have one obviously bad cell and others are not too bad so you may see more improvement than I did where a lot of my cells were degraded. (There was an 8Ah spread between best and worst cells - 32Ah for the worst, 40Ah for the best...)

 

[Pepin]

Can the Lexia/Mut reinstall or upgrade any kind of firmware for the BMU or CMU?. It´s possible to make a factory reset with new software for all electronic elements of the car? .

I don´t know if Psa/Mitsu have a new software.

 

[Mars]

Hi !

My issue that started only in cold weather is now permanent.
Heating the battery and erasing all error codes with Diagbox (PSA tool) I could restart the car, but the voltage readings on CMU_10 are still jumping all over the place on 3-4 cells of the module.
Not bad enough to completely disable the car (like it was during this winter) but still errorous and unreliable.

Those issues on CMU_10 can't be a coincidence, maybe it is the board that sees the most temperature cycles, thus fails most of the time ? Hard to tell.

Anyhow, I might have found a company that could repair my battery.
Since the car would need to be transported over several hundred km, I really need to know this is going to work before I give it a go...

In this thread, it was said a CMU board needs to be programmed to learn the cells modules it is supervising. The repair guy says that if we're going to swap the CMU_10 board we need to source a used CMU_10 board (not another number). So about that, it matches the idea that CMU boards are programmed and apparently cannot be reprogrammed.

On the other hand, he is not aware of the fact that the CMU board is VIN programmed. In other words, a CMU_x board from a used vehicle could be used as is in any other vehicle, as long as it is replacing a CMU_x board (not a CMU_y or CMU_z...). If the module number matches, it should be fine he reckons.

Does anyone has a verified information about that question. Are CMU boards VIN programmed or not ? Are they car swappable if CMU module number matches ?

Cheers and good luck

 

[MickeyS70]

CMU boards are not VIN coded but they need to be uniquely numbered (1-12) I.e. there can be no two the same. It’s possible, as an example, to swap a CMU03 from one car to another.

There are several options to re-ID a working CMU for another source. A quick way is to swap the ID chip physically. One can also read out the information of one and write it to another board. If you have access to a MUT3 diagnostic tool you can re-ID the boards in situ.

A different possibility altogether would be to ‘fix’ the issue by correcting the faulty data with a CAN bridge (sounds more complicated than it is) on the BAT bus which could be done at home, DIY style.