Battery capacity got reset after changing aux battery

[rnlcarlov]

Some days ago my C-zero wouldn't turn to ready and it was caused by a faulty 12V battery.
I bought a new one and left the old one at the store, and then had to come back the next day because I needed terminal adapters that were left in the old one (go me :roll: )

Anyway, I installed the new battery and the car goes to ready now, although the warning ! light remains on.
I drove it for 60km and saw that I still had 60% SOC, which was unrealistic as it's a 2011 car. I checked CanIon and the car now considers it has a 46Ah battery.
I checked the DTCs and the active relevant ones seem to be these:

U1116
Raw code: D116
ECU: Dashboard/Meter #2
Mitsubishi: SCP (J1850) Invalid or Missing Data for Electrical Energy Management; KOS CAN timeout/Not equipped

U1111
Raw code: D111
ECU: BCM/ETACS #2
Mitsubishi: SCP (J1850) Invalid or Missing Data for Primary Id; Display CAN timeout/Not equipped

As well as P1A51 and P1AE6. It appears than even though it was only without aux battery for a day, the car forgot the status of the main battery. I can drive normally, but I'm sure I can't rely on the gauge to know how much range I've got.
The car sometimes recalculates the available battery capacity, right?

I was thinking of clearing these DTC and see how things went. Does anyone remember how far in between does the imiev calculate capacity?

 

[MickeyS70]

Hi there

It certainly looks like your battery capacity was reset although you’re correct, this should not have happened during a quick 12V battery swap. You may have an underlying problem with your BMS or could the pos battery cable been touching the chassis ground overnight?

Some members ended up with the same issue after accidentally ‘going a step too far’ with their diagnostic tools but could quickly recover by running a ‘battery calibration procedure’ (about a day)

Others had enough patience or no access to diags and let the BMS correct the capacity over multiple charge/discharge cycles, works also, but that can take weeks or months before succeeding.

Mickey

 

[rnlcarlov]

So I did a forum search, and that ‘battery calibration procedure’ requires that MUT-III tool, correct?
Guess I'm out of luck then. The long road it is for me.....

 

[MickeyS70]

So I did a forum search, and that ‘battery calibration procedure’ requires that MUT-III tool, correct?
Guess I'm out of luck then. The long road it is for me.....

Not necessarily, someone mentioned that the HobDrive (Beta) app has a similar function…

 

[kiev]

The car will do a calibration if you run it down to 2 bars or less on the fuel gauge and then charge it back up to full.

The Uxxxx trouble codes are related to an issue with the CAN communication buss, which usually happens when the 12V battery gets too low.

The P1A51 and P1EA6 are related to an eeprom error in the BMU. When you shut the car off the BMU is still active for a few seconds as it writes some data into the eeprom. If the 12V battery failed or was disconnected while the Key was On or in READY mode, then the data-write process could have been corrupted by the interruption.

 

[MickeyS70]

The car will do a calibration if you run it down to 2 bars or less on the fuel gauge and then charge it back up to full.

Agreed, but it seems the BMU is very reluctant to do the extreme changes in one go and opts for a more gradual approach?

Could you post the new value after completing the first full charge cycle as described by Kiev?

 

[rnlcarlov]

I'm pretty sure the battery won't last until only 2 bars are left. My best bet might be go as low as I feel confortable with and use A/C or something until I get the turtle sign. It should turn on below a certain voltage, right? It's not just at 9,5% SOC, right? I have I feeling I saw a car with 26Ah do that.

 

[CZeroOwner]

I'm pretty sure the battery won't last until only 2 bars are left. My best bet might be go as low as I feel confortable with and use A/C or something until I get the turtle sign. It should turn on below a certain voltage, right? It's not just at 9,5% SOC, right? I have I feeling I saw a car with 26Ah do that.

The recalibration process may also work if the SoC% is less than 70. Say 60% to be sure. The important thing is that the BMU pauses slow charging for about 10 min. The BMU uses this pause to measure the true SoC% of the battery based on the battery voltage at low current. On my CZero 2011 the BMU's does this at 20% or at 70% depending the SoC% when charging starts. I believe there is a limit to how much the BMU's capacity estimate changes in each calibration but I don't know what that is. I would very much like to hear what you observe.

 

[rnlcarlov]

The recalibration process may also work if the SoC% is less than 70. Say 60% to be sure. The important thing is that the BMU pauses slow charging for about 10 min. The BMU uses this pause to measure the true SoC% of the battery based on the battery voltage at low current. On my CZero 2011 the BMU's does this at 20% or at 70% depending the SoC% when charging starts. I believe there is a limit to how much the BMU's capacity estimate changes in each calibration but I don't know what that is. I would very much like to hear what you observe.

Oh, those stops. Yes, mine stops at 70% and 30%. The 30% used to be a headache for me since our public chargers detected that long pause as an interruped charge and ended the charging session :roll:

 

[CZeroOwner]

Oh, those stops. Yes, mine stops at 70% and 30%. The 30% used to be a headache for me since our public chargers detected that long pause as an interruped charge and ended the charging session.

That must be irritating. And your right it is 30% and not 20%

 

[rnlcarlov]

That must be irritating. And your right it is 30% and not 20%

I had to connect a 100W lamp together with the EVSE to fool public charger and be able to charge all the way. Fortunately a friend of mine works for the company that made many of those first chargers, so eventually their firware settings were changed as to not time out.

 

[coulomb]

That must be irritating. And your right it is 30% and not 20%

I had to connect a 100W lamp together with the EVSE to fool public charger and be able to charge all the way.

Yikes!

Also, how did you accomplish this?