tinoale
Posts: 39
Joined: Wed Apr 23, 2014 6:36 am

Re: not charging my iON, cell or CMU or BMU problems

Sat Apr 20, 2019 9:39 am

BTW the errors codes I pulled :


BMU :
P1A7F and P1A4B

EV ECU :
P1A39
P1A33
P1A2F
U1113

I also has some CAN bus error codes (lack of communication or communication errors) but the repair guy said we should not worry too much about them, as a weak 12V battery can make them pop up.

Those I noted here are the ones that come back quickly

coulomb
Posts: 166
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: not charging my iON, cell or CMU or BMU problems

Sat Apr 20, 2019 4:53 pm

tinoale wrote: 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).

I've been reading the CMU firmware. It's hard going for me, but there is definitely a mechanism for "numbering" the CMUs. In fact, it seems to me that this happens automatically any time that there is a certain type of error (I can't be certain about what type of error, and it was some time ago I that I found this). But I have no idea how to trigger this process if needed. [ Edit: It's possible that the CMUs will detect say two CMU 5s and/or no CMU 10, and that this mismatch will automatically trigger the renumbering process. It has to originate from the BMU. ]

So my conclusion is that you don't have to get a particular numbered CMU board, but I don't know how to make the renumbering happen. Perhaps there is a function on the MUT-3 that triggers it. Or some special CAN bus message.

Of course, you'll need an 8-cell board, not a 4-cell board, so it can't be from a CMU 6 or 12 (those are the 4-cell boards).

Not much help I know, but it might be able to be pieced together with other clues.

kiev
Posts: 920
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: not charging my iON, cell or CMU or BMU problems

Sat Apr 20, 2019 8:02 pm

The is a reference to cell numbering in the description of the BMU pins 48 and 49:

1 Auxiliary battery power source
2 EV-ECU control power source
3 BMU earth
6 CAN interface (high)
7 CAN interface (low)
8 K-LINE
12 Main battery cooling fan relay
13 Main battery cooling fan PWM signal
21 Input signal for main battery cooling fan speed
31 Applied voltage for main battery current sensor
32 Main battery current sensor (high)
33 Main battery current sensor (low)
35 Main battery earth leakage sensor
37 Local CAN (for main battery) interface (high)
38 Local CAN (for main battery) interface (low)
42 Main battery current sensor earth
43 Main battery current sensor earth (shielded)
46 Main battery earth leakage sensor pre-check signal
48 CMU ID automatic number input signal
49 CMU ID automatic number output signal
kiev = kenny's innovative electric vehicle

tinoale
Posts: 39
Joined: Wed Apr 23, 2014 6:36 am

Re: not charging my iON, cell or CMU or BMU problems

Sun Apr 21, 2019 1:25 am

Hi!

Super interesting info, would be cool to tinker with this. But I have found a CMU 10 board set (board, wiring and space board) of eBay though so apparently I won’t need this auto numbering function.

Have you any info about the CMU board being VIN programmed ?

coulomb
Posts: 166
Joined: Sun Jun 10, 2018 8:32 pm
Location: Brisbane, Australia

Re: not charging my iON, cell or CMU or BMU problems

Sun Apr 21, 2019 3:53 am

tinoale wrote: But I have found a CMU 10 board set (board, wiring and space board) of eBay though so apparently I won’t need this auto numbering function.

Oh, I forgot to mention that as far as I know, the ID resides in RAM. If so, all the 8-cell CMU boards would be the same, and you'll need it anyway. But there might be somewhere it reads that ID from, that I haven't noticed.

Have you any info about the CMU board being VIN programmed ?

I've not noticed anything [ edit: in the CMU firmware ] that I have associated with VIN numbers, but there are plenty of things I don't understand, one of which could be a VIN number. Others may have more direct information, like "I tried it and it didn't work till the dealer did some magic".

Gary12345
Posts: 26
Joined: Tue Feb 12, 2019 4:15 am
Location: Essex, UK

Re: not charging my iON, cell or CMU or BMU problems

Tue Apr 23, 2019 3:02 am

** Just realised this is a really old thread - note to anyone else reading!! **

Hi, i just fixed the same issue on my i-miev. It is failure of the voltage monitoring chip on one CMU, the board in one of the battery modules. Mine was also pack 10, so it seems these pack 10 chips like to die.

I got a new chip and took it to a mobile phone repair guy to get him to swap the chips, this saved any hassle with reprogramming the CMUs.

MUT 3 can do the reprogramming but this is hassle, it is much easier to get the chip replaced, if you look at the circuit board you will find chip LTC6802-G2. You need to get this chip replaced. I bought it from one of the electronics suppliers, I think it was Rapid Electronics.

Are you confident which is CMU10?

Also are you using an iCarSoft i909? This gives you an explanation for all the error codes, makes it much easier but the ones you give are almost exactly the same as I had.

Thanks,

Gary.

tinoale
Posts: 39
Joined: Wed Apr 23, 2014 6:36 am

Re: not charging my iON, cell or CMU or BMU problems

Tue Apr 23, 2019 11:03 am

Hi Gary

Good info, quite reassuring that the issue really seem to be confined within the CMU board.

I use DIAGBOX to say that it is CMU number 10 that is failing.
On Canion, I see voltage issues on cells number 71 72 73 74.

I do not know, as of now, where is this board physically located. Any pointer to this information would be greatly appreciated.

Anyhow I have found a CMU 10 board on eBay for a decent price. My idea at this point is to swap the whole CMU 10 board.

My problem now is to find someone willing to do the swap or let me use a garage spot for a day so I can do it. There is one company but far from where I am, transport and repair will cost me 1k€ overall.

How silly does it sound that the car is made useless because of a 10€ chip :roll:

Edit :
Gary do you confirm this is what you issue looked like : first at the beginning, second more recently (more severe) ?
https://youtu.be/VFCCpODjg-s
https://youtu.be/cuBEsbJZcg0

kiev
Posts: 920
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

Re: not charging my iON, cell or CMU or BMU problems

Tue Apr 23, 2019 6:58 pm

The LTC6802 cell monitoring chip does not have direct access to the CAN buss and does not receive or store the CMU number. There is a microcontroller chip that communicates between the LTC chip and the BMU, and [edit: the CMU number is stored on an eprom on the board.] No VIN coding used or required.

If it is defective in reading a cell voltage, then it could be the source of an error or issue.

Was CMU 10 in the 2nd from the front right location as shown in this diagram?

Image


@tinoale, so your cells have voltage jumping around intermittently. does it affect your range? can you still charge full up to 16 bars?

There are 2 circuit boards for the 8-cell CMUs and it appears that you have a bad reading on 2 cells from each board. It would great to inspect the bad boards after you swap them out to determine the root cause.
Last edited by kiev on Fri May 17, 2019 11:04 am, edited 1 time in total.
kiev = kenny's innovative electric vehicle

Gary12345
Posts: 26
Joined: Tue Feb 12, 2019 4:15 am
Location: Essex, UK

Re: not charging my iON, cell or CMU or BMU problems

Fri Apr 26, 2019 6:14 am

tinoale wrote:I do not know, as of now, where is this board physically located. Any pointer to this information would be greatly appreciated.


Hi,

Your videos show exactly the same issue as I had, where voltages jumped up and down, mine was also CMU10. I would not buy a replacement CMU, instead fix the one you have like I did, otherwise you may find that the board you buy will not communicate with the BMU, it may not really be number 10, etc, etc.

When you take the battery pack out, there are 10x 8-cell modules, (and also 2x 4-cell modules if its a 16kwh pack). Using the diagram that kiev posted, identify which is module 10.

Disconnect the little communications connector, take the bus bar off and get module 10 out, remove the metal end caps and metal cover, then pop off the plastic cover and you can see the CMU board - there is one of these on each battery module.

You will be able to see the LTC6802-G2 chip - can you order one of these and then get someone to swap it out (laptop/mobile phone repair guy?).

Please ensure you follow the mitsubishi safety instructions for safe removal of the battery pack - it also weighs 240kg but i did all this on my driveway with 2 jacks and concrete blocks !

Thanks.

Gary12345
Posts: 26
Joined: Tue Feb 12, 2019 4:15 am
Location: Essex, UK

Re: not charging my iON, cell or CMU or BMU problems

Fri Apr 26, 2019 6:16 am

Since it is likely you cannot see the failure (for me the chip looked fine but did not work properly) If you want to confirm that you have the correct battery module, just disconnect the little communications connector, then reconnect the battery pack multi plugs and check the battery voltages, the one that was jumping up and down will now have disappeared.

thanks.

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