Tesla model 3 BMB control boards

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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Trace M3 balance board 2.rar
(51.08 KiB) Downloaded 14 times
2nd balance board...
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Re: Tesla model 3 BMB control boards

Post by tom91 »

hanskraayeveld wrote: Tue Oct 07, 2025 4:48 pm Trace M3 balance board.rar

Its original a *.sal file, but I could not upload it, so zipped it
I have reviewed the SPI comms, there seems to be no data coming back from the BMB. The batman on the BMS board seems to be sending some info, or atleast responding to SPI commands. Yet when looking to read data from a BMB nothing is passed on.
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Re: Tesla model 3 BMB control boards

Post by Jack Bauer »

Can you please remove IC4 from the board. MAX17841. That should solve the problem.
I'm going to need a hacksaw
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Re: Tesla model 3 BMB control boards

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Re: Tesla model 3 BMB control boards

Post by Jack Bauer »

Excellent!
I'm going to need a hacksaw
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Re: Tesla model 3 BMB control boards

Post by tom91 »

hanskraayeveld wrote: Fri Oct 10, 2025 5:20 pm
So removing the MAX chip that is also on the SPI bus solved it. Good to note this for this hardware version.

I only even worked on M3 on older version and now ONLY the MAX on the new version.
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

I also connect 4 modules, changed parameters to 4 modules, plugged two wires in one connector on hvc, other connected to hvc, but little data?
After it, I plugged out other connector from bmb4 to hvc, but same data.

After it connect to one module again, same... little data.

Is it unstable?
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Re: Tesla model 3 BMB control boards

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Screenshot_20251010_211912_Samsung Internet.jpg
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Data is very unstable...

Now its not displaying voltages anymore... somethimes some temperatures
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Screenshot_20251011_043402_Samsung Internet.jpg
Screenshot_20251011_043357_Samsung Internet.jpg
After a night, cell voltages are back ...
Sometimes temps comes and then go...
I select balancing on, first time showing 23 balancing, now none...

What could be the problem?
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Other board is working fine... So I have one board which was working good, now not.
One board is working on one module. I am afraid to test it on 4 modules, maybe I ruïned the other also :(

So next for me to do is a small modification on balancing.
17601561675003115806303802753671.jpg
I want to change this line:

umin to umax
+ BalHys to - BalHys

I want to balance from top to bottom. So first bleed the highest...

I can change in code really simplex, but the question is: how to upload :?

No experience with it. I can save file, but normally I work with arduino or teensy.

I think I have to convert all (included) files to a bin file, and then upload it.

Could anybody help?
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Re: Tesla model 3 BMB control boards

Post by tom91 »

hanskraayeveld wrote: Sun Oct 12, 2025 4:19 pm Now they are working, and know what the problem is
Please explain what you changed to now get the data working again?
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Re: Tesla model 3 BMB control boards

Post by tom91 »

The M3BMS software is written based off of Open Inverter libraries and bootloaders. The same as the STM32_VCU aka Zombieverter. Others and I create more info on how to build the code in the readme for the Zombieverter code base: https://github.com/damienmaguire/Stm32- ... IBUTING.md
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Re: Tesla model 3 BMB control boards

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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

tom91 wrote: Sun Oct 12, 2025 4:26 pm Please explain what you changed to now get the data working again?
1 is good working, other is not working good, somethimes, I'll replace batman chip, I think resistance is too low faom some legs to eachother
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

What happened if I connect a 108 bricks LFP battery?
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Re: Tesla model 3 BMB control boards

Post by tom91 »

Do you have info on the BMBs used? Never been done before so could need some tweaks.
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Did a update to both boards....

With STM programmer. What a hell of a job... Without Tom, never succeed...

I replace very little:
Balance voltage is highest cell voltage - balhyst (0.002v)

Hopefully it will balance nice....
Screenshot_20251013_221958_Samsung Internet.jpg
Screenshot_20251013_222227_Samsung Internet.jpg
7 mv imbalance

8 cells balancing
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Re: Tesla model 3 BMB control boards

Post by tom91 »

Possibly is not fully working, I had it working on my bench on 18650s with a 24s BMB, I now also have 23s and 25s BMBs to look at on the bench.
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

I have now a Standard Range battery, so 4x 24 cells.
Next Ill try a Long Range, 2x 25 2x 23 cells.
After it an LFP 108 bricks.

http://portal.greenaid.nl/TBC%2024015
Tesla Model 3 SR battery as home battery, still balancing now with Damian/Tom tool
http://portal.greenaid.nl/TBC%2024000
Tesla model S battery also as home battery, connected to Tesla M3 battery, still working

http://portal.greenaid.nl/TMC%2025004
This is a Tesla model S battery balancer. (Based on Toms simpbms) Only better ;)
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Screenshot_20251014_074135_Samsung Internet.jpg
Screenshot_20251014_074144_Samsung Internet.jpg
After a night, seems cell balancing does not do anything (spectacular) (Can be my fault)

Question for makers: cell balancing M3 module is done by resistance wire, right?

1: How did you imitate this on a bench?
2: When balancing, cell voltage is not available (shorting wires), how is voltage measurement performed when balancing? Balancing stops for a few ms?
3. Why is uavg not matching, also before I do modulifications
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Screenshot_20251014_083318_Samsung Internet.jpg
Screenshot_20251014_083329_Samsung Internet.jpg
I think he is doing something. But what?
5mv imbalance
52 cells balancing
It seems the lowest is more rising in state of the highest are decreasing...
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Re: Tesla model 3 BMB control boards

Post by tom91 »

hanskraayeveld wrote: Tue Oct 14, 2025 5:47 am Question for makers: cell balancing M3 module is done by resistance wire, right?

1: How did you imitate this on a bench?
2: When balancing, cell voltage is not available (shorting wires), how is voltage measurement performed when balancing? Balancing stops for a few ms?
3. Why is uavg not matching, also before I do modulifications
1. request balancing and check feedback from the BMBs, as I said I will look to find some time soon to revisit this.
2. Before requesting a measurement balancing is paused. This maybe the reason balancing is not happening porpperly.
3. No idea can take a look when having everything set up again.
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

I measured the amps (with a very percisely meter) and I measure its balancing.

I measured parallel the brick wire. The last and first brick wire current is flowing one way.
The middlest brick wires, current is flowing forward, a sec, and back a sec.
So it is bleeding, for sure...
So it seems it cannot bleed all bricks the same time.

Am I right?

I hear also something clicking on bmb every 2/3 sec
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Screenshot_20251015_062544_Samsung Internet.jpg
Screenshot_20251015_062602_Samsung Internet.jpg
4mv imbalance
89 balancing
After 29 hours working time

Works nice for me, as expected, only little speed up ;)
I measured balancing/bleeding time is approx. 25%
Hopefully Tom can speed it up to 95%. 5% for measuring voltage.
He also did that for model S.

Tom is working on it... So fingers crossed
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Re: Tesla model 3 BMB control boards

Post by hanskraayeveld »

Screenshot_20251015_175856_Samsung Internet.jpg
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Cells balancing 95

Screenshot_20251015_174112_Samsung Internet.jpg

I stopped balancing today, this is can readout.
If I had more time balancing would be perfect balanced within 1mv
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