[Tomdb]

I have been able to decode some of the I3 battery Can bus.

Currently I have working:
-Cell Voltages

Should be able to get the following with the info I have:
-Temperatures

Need to do some logging to get the following:
-Balancing Commands

Have now implementened the code to work with my SIMP BMS, this means the 'base' features are retained.

https://github.com/tomdebree/BMWI3BMS

 

[Steel]

Hello, Tomdb !
Nice hearing about some progress I have a I3 batterypack and I'm very happy about this !!

BR Pär

 

[thomas11]

Jumping in on this topic:

I m planning on buying a BMW i3 120Ah 45V battery for my electric motor for my dinghy.

Am I correct that it is not possible to get balancing/temp BMS for this battery without completely altering the battery? There is a nice cable that goes to all the cells but if there is no BMS that you can connect to this it will be not safe especially on the water if something goes wrong.

 

[kennybobby]

Re: Bmw i3 module and cell monitoring board

Paul bought a module and brought it by so i could take a look. Sorry for the poor images, it was quite warm out and spur of the moment to grab a quick picture of the board.

The module is quite heavy with 12s cells which seem to be Samsung cells (made in Korea) of about 50-55 Ahr. Cell dimensions about 7" x 2" x 5.5". Wrapped in a housing made of 6016-T4 aluminum. All welded terminals and measuring taps, so it won't be easy to reconfigure; but it's package so compact and well that it would be easier to just use as is.

The cell monitoring board uses a pair of LTC chips, one does the management, the other just provides a safety monitor according to the datasheets. This provides a bit of redundancy such as found on the tesla 3 and reported by Jack on evtv.

The balancing must be about 75mA with these 56R large-sized resistors in the world of surface mount. ~0.32 Watt

We could probably get better photos and more schematic details if needed.

 

[pdove]

The Processor on the board is MC9S12P 64-pin package from Freescale Semiconductor used to be NXP. It also uses Si 8422AD isolator chips to talk between modules.

You can see on the lower board that pins 59 and 60 of the MC9S12P run across the board through a via to the other side and go to the Si 8422AD chip to the isolated part of the board and then run to the smaller connector the 12 pin one. They go to Pins 4 and 10 (CanL) and pins 5 and 11 (CanH) this connector goes daisy chain between the modules.

 

[pdove]

The bigger connector goes to the cells and to an LTC6801 and LTC6802 to monitor the voltage and the temperature of the cells. Looks like there is a diode between each cell most positive --|>|-- to negative across cell. Looks like the 6801 is used for discharge and 6802 is used charge and balancing the diodes go the --|<|-- on the 6802The bigger connector goes to the cells and to an LTC6801 and LTC6802 to monitor the voltage and the temperature of the cells. Looks like there is a diode between each cell most positive --|>|-- to negative across cell. Looks like the 6801 is used for discharge and 6802 is used charge and balancing the diodes go the --|<|-- on the 6802

 

[colourmecarbon]

very interested in this thread, I’m hoping to convert my Type2-only i3 charging port to a CCS with fast-DC version.
I can’t find detailed part number info for the BEV models that have the ccs-dc, so I don’t know if the KLE EMS are bypassed and the HV cabling goes directly to the battery.
From what you’ve found in the BMS, do you think it would be possible to directly connect the DC pins to charge the battery and let the BMS control the input without major work to the onboard charging components?

 

[kennybobby]

These are just the CMU board found on each module--Cell Monitoring Units that can only report back thru the CAN buss to some higher-level controller such as a Battery Management System or BMS unit.

i haven't studied up on the i3 system so this is just based upon my experience with other OEMs: The BMS likely talks to an even higher level Electric Vehicle Control Unit, which handles the communication between the car and the Chademo or CCS DC station, aka EVSE Level 3. Due to safety concerns with HV i'm sure that chargging is controlled at a much higher level than these CMU boards.

You may be able to use Tom's board to integrate some sort of diy controller for the cell voltages, but i'm not sure that anyone has reverse engineering the level 3 protocol. Anyone know if it has?

 

[pki]

Hi.

I have installed the i3 battery pack into our EV. I have a few basic questions.
- Does the BMS modules on each battery pack will work stand alone, or do they need more?
- I also have the SME BEV13 D1 module, i think the BMS management?'
- I also have the onboard charger box.

I would like to get the AC charging to work. Do I need more from BMW, or should this parts be sufficent and can work without the other electronic from BMW?

 

[colourmecarbon]

is the car you’re building an i3 or a custom diy conversion?

 

[pki]

Its a converted berlingo with MED-DEA/Venturi drive, the drive is working, i am working on a way to charge it.