MG5 LR Battery

[yasko]

I'm sharing information about the MG5 LR battery I used in energy storage projects.

The 61kWh battery has a 96S1P configuration and uses giant 174Ah NMC cells from CATL.
The cells are arranged into six modules with two 8S groups.

Marking on the battery module:

Arrangement on the cell's group:

Each block has a BMS module:

Inside BMS module:

The BMS has two sections for monitoring each 8S cell. It's based on ADBMS6815, a new-generation BMS chip from ADI. It can monitor up to 12S cells.
Unfortunately, it is under NDA, and the full datasheet isn't available to the public. I think this chip is the successor to the popular LTC6811.

A picture of the primary BMS:

It uses LTC6820 for ISO-SPI communication with slave BMSs.
I was able to reuse the slave BMS modules; more on that in the following posts.

And finally, here is a picture of the battery without electronics and cables:

[marcexec]

Do you have dimensions of the modules so it can be added to https://openinverter.org/wiki/Batteries#OEM_modules?

[jamesn]

Hi Yasko,

Any updates on taking control of the slaves?

I've just bought and MG5 pack with only 800 miles on it so I was very happy to come across your post and get a first look inside what I've bought.

[yasko]

Hi Jamsen,

I have used the slave BMS modules and can help in this direction. But this will require some programming.
The ADBMS6815 is under NDA, which complicates the situation. Unfortunately, I cannot share the full datasheet.

My approach was to start with the code for LTC6811 and modify the code to work with ADBMS6815:
https://github.com/analogdevicesinc/Lin ... es/LTC6811
I'm using custom hardware based on STM32G491 MCU.

Also, I've searched the Github and found this:
https://github.com/526766987/Battery_Ma ... tem_36cell
It's based on STM32F407 + ADBMS6815 - I didn't test this, but it looks like a good starting point.

So, what hardware platform are you planning to use? You will need a LTC6820 for iso-spi communication.

@marcexec—I don't have the exact dimensions. Maybe Jamsen can help when he opens the battery.

[Jacobsmess]

I'm interested if there has been any more development on this?

Thanks

[jamesn]

We have gone a completely different route.
The battery hasn't been opened, we have got it to start up on the bench by playing various CAN logs to it. We just need to keep distilling down now until we can write a basic sketch for an ESP32 or maybe add it to the Battery Emulator Project.
We have got a V2L charger from an MG5 so the ultimate plan now is an off grid setup using the charger as an inverter.

[T1Terry]

We have gone a completely different route.
The battery hasn't been opened, we have got it to start up on the bench by playing various CAN logs to it. We just need to keep distilling down now until we can write a basic sketch for an ESP32 or maybe add it to the Battery Emulator Project.
We have got a V2L charger from an MG5 so the ultimate plan now is an off grid setup using the charger as an inverter.

I am doing that with an LFP battery in the MG4 51 SR, but still in the car as we also use the car as a daily driver. I have a total write off MG4 with the NMC 61 pack in it and this might be an interesting project for that battery.

I'm still trying to decide which of my yard full of vehicles would be the best choice for the motor, or if I should make an EV track car out of it and just use the battery while at home with the V2L when not playing silly buggers with it .....

T1 Terry

[Jacobsmess]

There is some information on on the can comms from the BMS on the open dbc I think.

The MG batteries are very cheap on ebay atm and plentiful.

[jamesn]

Funnily enough the CAN logs I'm playing back are actually from an MG ZS so it wouldn't suprise me if the required CAN messages are the same between the 4/5/ZS or maybe even further across the SAIC vehicles.
I did get a few captures from an MG5 I had access to but the most comprehensive/useful logs that I have used are on Damien Maguire's GitHub under the MG Charger page.
Just in case that's helpful in getting your MG4 battery running. It would be really useful to know if the same codes work across the whole range.