# Tesla Model 3 Battery - How do you communicate with the BMS ?



## Truesolutions (Mar 14, 2018)

Have managed to get a Tesla battery from a 2021 Model 3 (60kw)

(S) Tesla serial number: TG322020000WN1
(P) Tesla part number: 1666969-00-C

What trying to do is work out how to connect to the BMS slave boards that on the modules

Found that its meat to have setup like this inside with 4 long modules (Diagram found on you tube video)
From this Video : 














This one has good info on tear down : 



And show modules inside


I found this git project, which seem to be a great start if it still works for my battery setup








GitHub - collin80/TeslaBMS


Contribute to collin80/TeslaBMS development by creating an account on GitHub.




github.com




Where show its serial coms out of boards not can
https://cdn.hackaday.io/files/10098432032832/wiring.pdf


The modules seem to have Serial boards that let you get info about state and the balancing of the battery
So will try get few parts and try that code out
Need a 3.3v to 5v serial adaptor first as Arduino DUE boards wont like the 5v only will handle 3.3

So the questions part, 100% new with Tesla (Only played with leaf BMS to date)
Is these any good website to view that may help with any of the following

1) What's the wiring info on these two plug that come out of the tesla modules
(Is one each side of the pent house box)









2) Any other site that may have the Serial decoding information for what comes out of the modules
I hope GitHub - collin80/TeslaBMS will still work bit wondering if any updates

3) Any product on the market that we can connect to these slave boards and get a can message output ?

4) As an aside any one know how to decode serial number on box 
( just keen to confirm what I was sold is actual what got)


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## remy_martian (Feb 4, 2019)

It's extremely rare for these modules to fit in any vehicle, let alone the full pack.

What vehicle is this for?


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## kennybobby (Aug 10, 2012)

That's a great video find.

The little boards on the cells don't show any bleed resistors for balancing, maybe they are on the bottom side?

Those boards look to have 2 or 3 microcontrollers and 3 HV isolation chips, one is sending the signal to the output connector that reaches into the penthouse. Inside the penthouse are numerous components for HV: main contactors, pyrofuse and master bms board. Likely that the CAN buss communicates from the master to the vehicle, and serial comm from cell boards to master.

i thinkCollins work was on the old cell monitoring boards which had a dedicated bms chip talking to an 8051 microcontroller that talked to the master bms board on a serial daisy chain.

Did your pack come with the penthouse?


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## reiderM (Dec 30, 2020)

That github repository is for s/x modules only. This is what you're looking for:









GitHub - damienmaguire/Tesla-Model-3-Battery-BMS: Reverse engineering of the Tesla Model 3 battery bms control


Reverse engineering of the Tesla Model 3 battery bms control - GitHub - damienmaguire/Tesla-Model-3-Battery-BMS: Reverse engineering of the Tesla Model 3 battery bms control




github.com










Tesla Model 3 BMS Controller


Electric Vehicle (EV) conversions of BMW cars and related technologies.



www.evbmw.com


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## Truesolutions (Mar 14, 2018)

remy_martian said:


> It's extremely rare for these modules to fit in any vehicle, let alone the full pack.
> 
> What vehicle is this for?


Im looking at them for Landrover and small trucks, but this one planned for my boat
Lots of space, we did test with Leaf battery but lacked the range.


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## Truesolutions (Mar 14, 2018)

kennybobby said:


> That's a great video find.


Yea super fast mat video showed more than most

This video is good also








kennybobby said:


> The little boards on the cells don't show any bleed resistors for balancing,
> maybe they are on the bottom side?
> 
> Those boards look to have 2 or 3 microcontrollers and 3 HV isolation chips,
> ...


That is what I think also that Collins work is for different modules
They still seem to have serial connections off them so will try and connect and see what I can get out.

Is a board in box that seem to connect to all them, which is can output
Will see what I can find out about that, its basic of wiring and modules to use and codes that need to undertand




kennybobby said:


> Did your pack come with the penthouse?


Yes got a complete pack photo's from what I have now, striping down penthouse now


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## Truesolutions (Mar 14, 2018)

reiderM said:


> Tesla Model 3 BMS Controller
> 
> 
> Electric Vehicle (EV) conversions of BMW cars and related technologies.
> ...


Not full studied that yet but is that now with what he calls the batman chip included ?



reiderM said:


> GitHub - damienmaguire/Tesla-Model-3-Battery-BMS: Reverse engineering of the Tesla Model 3 battery bms control
> 
> 
> Reverse engineering of the Tesla Model 3 battery bms control - GitHub - damienmaguire/Tesla-Model-3-Battery-BMS: Reverse engineering of the Tesla Model 3 battery bms control
> ...


I will have look at that also but it also mentioned link for updates


Tesla Model 3 Battery Hacking - openinverter forum


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## Tomdb (Jan 28, 2013)

Model 3 Chips used are not available anywhere but from a salvaged pack. So you would need to pull the ics of donor boards, which are conformally coated. Then solder these on a dedicated board like the one Damien designed.

All of this has to be done due to the fact Tesla use the base chips but operate it outside of the "standard" communication speed and with a custom instruction set. 

I was able to contribute by decoding the custom protocol to some extent. However all this was halted as no others pitched in and I or Damien did not have a direct need.


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## kennybobby (Aug 10, 2012)

Are you going to remove the penthouse and replace it's functions with other hardware/ boards? 

Why not just use the CAN buss to query the pack; you ask about reading serial data, then in (3) you ask about interfacing with CAN...what is it that you want to do?


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## Truesolutions (Mar 14, 2018)

Tomdb said:


> Model 3 Chips used are not available anywhere but from a salvaged pack.
> So you would need to pull the ics of donor boards, which are conformally coated.
> Then solder these on a dedicated board like the one designed.


I have seen some of the video that Damien did and not sure my board is the same
The wiring you guys connect into looks different

I just have 2 wires from the modules, plug like this each side of the battery box
Just two wires out from it with green and white wires
(No sign of the 5 wires shown with a GND/Power/Fault wires etc that see in diagrams)








(And I broke the plug so have to fix it)


So @Tomdb does this look like what your guys based your discovery off, or have they change it again ?


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## Truesolutions (Mar 14, 2018)

kennybobby said:


> Are you going to remove the penthouse and replace it's functions with other hardware/ boards?


Want to remove the pent house and connect to modules directly to get info.
So after something that can read and give me date back.



kennybobby said:


> Why not just use the CAN buss to query the pack;
> You ask about reading serial data, then in (3) you ask about interfacing with CAN...what is it that you want to do?


That what trying to understand is it CAN or Serial that comes out of the module I have.

See above post where I put image of what plug looks like its only 2 wires so does not match the serial coms wiring that people suggested


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## Truesolutions (Mar 14, 2018)

Tomdb said:


> I was able to contribute by decoding the custom protocol to some extent. However all this was halted as no others pitched in and I or Damien did not have a direct need.



Was just looking at the video again and I was wrong above, Iv got my video mixed up that thinking of
Damien video is showing the two wires that I do have come from my module









His Git Repo: GitHub - damienmaguire/Tesla-Model-3-Battery-BMS: Reverse engineering of the Tesla Model 3 battery bms control (Im guessing its your repo also @Tomdb)
The board he is selling: Tesla Model 3 BMS Controller

@Tomdb so if I dont have the Batmanchip what will get native from the 2 wires from the module ?
Im guessing that batman chip just some translator, wondering what the raw info give.

This is the other project that was looking at and it talks on the 5 wires and people using a teensy to ready data from it.








GitHub - collin80/TeslaBMS


Contribute to collin80/TeslaBMS development by creating an account on GitHub.




github.com




https://cdn.hackaday.io/files/10098432032832/wiring.pdf


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## kennybobby (Aug 10, 2012)

Took me all day to finish reading Damien's openinverter thread.

From all the work that Damien and Tom did to try to decode the raw ISO-SPI signals, it appears that using the CAN buss thru the Master BMS board in the penthouse would be the easier way to get cell data. 

Or you could get Damiens FPGA board files, send off and get a board made, buy the common parts and solder them one, thenpull some batman chips off of used boards without damage, then soldering onto the board, then compile and program the FPGA to process what you want, etc...

Even Collin wasn't hopeful that he was gonna figure it out, but he is working for someone and his results will not be open source. i.e. won't be on github.


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## Truesolutions (Mar 14, 2018)

kennybobby said:


> Took me all day to finish reading Damien's openinverter thread.





Tesla Model 3 Battery Hacking - openinverter forum


Ive not fully looked at that thread yet, was started by a "Jack Bauer" is that Damiens handle ?



kennybobby said:


> Or you could get Damiens FPGA board files, send off and get a board made, buy the common parts and solder them one, thenpull some batman chips off of used boards without damage, then soldering onto the board, then compile and program the FPGA to process what you want, etc...











Hard to know from his description if he supplying the batman chip, and my soldering that good to do a 120+ chip
I sent email to ask him about it.





kennybobby said:


> Even Collin wasn't hopeful that he was gonna figure it out, but he is working for someone and his results will not be open source. i.e. won't be on github.


Maybe a product out their that Collin will sell soon, can be hopefull


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## remy_martian (Feb 4, 2019)

Ooh...he hates emails - if there's one thing that seems to trigger him it's 1:1 support.

Good luck on that one. You're supposed to ask on the forum.

I think it would be easier to just replace the damned slave boards.


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## Truesolutions (Mar 14, 2018)

remy_martian said:


> Ooh...he hates emails - if there's one thing that seems to trigger him it's 1:1 support.
> Good luck on that one. You're supposed to ask on the forum.


I have only asked him he he has stock of what he selling in his store and if Batman chip comes with it
Not asking for 1 on 1 support


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## Tomdb (Jan 28, 2013)

I would suggest reading the open inverter thread @Truesolutions

You are clearly drawing wrong conclusions based on your lack of understanding.
The batman chip does NOT come with it you have to salvage it yourself and its a pain. I have a written the code for a teensy 3.1 (not in stock anywhere at the moment but code can be ported to something else) to read and decode the ISO SPI traffic after querying the modules.

No idea how balancing is implemented no body has discovered that as far as I am aware.

I would strongly suggest keeping the Penthouse components are rehousing them if you want to use all four modules. Then talk to HV controller over canbus to get your info.


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## Truesolutions (Mar 14, 2018)

Tomdb said:


> You are clearly drawing wrong conclusions based on your lack of understanding.
> The batman chip does NOT come with it you have to salvage it yourself and its a pain


That is why I'm asking question to learn, and not make assumption.
I sent email to the store that listing a product to query what you get.

As unless I missed something on this stores product page, is nothing to indicate not complete.





Tesla Model 3 BMS Controller


Electric Vehicle (EV) conversions of BMW cars and related technologies.



www.evbmw.com





It actual says "All components supplied" but is mention that "Soldering required"
And conflicting information of *Availability:* In Stock and says "Coming Soon!"
And a photo of a completed board with a chip on it

It maybe that Damien just never got chance for listing the product so page not completed.
But hey, if I don't ask and he has them.
Then I would feel stupid that I wasted time making something I could buy.



Tomdb said:


> I would suggest reading the open inverter thread @Truesolutions


I am, I'm working through all links I find and making notes.


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## remy_martian (Feb 4, 2019)

Good - post those notes here. Shouldn't have to mention it.


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## Truesolutions (Mar 14, 2018)

remy_martian said:


> Good - post those notes here.


This is worth a read. its Toms work (Very good work)








Tesla BMS


As some of you might have been aware there has been some projects out there that have gotten the Tesla BMS slaves to work. I have participated in a few. Currently I am working on getting software written to do all the basics like: -Overvoltage monitoring -Temperature monitoring -Undervoltage...




www.diyelectriccar.com




GitHub - Tom-evnut/TeslaBMS

Its not the direction I'm wanting though
Its using CAN bus from master bms board (Not direct to slave modules)
Which is great option,
I will most likly go done discovery path and end up circling backing and using this proven method after wasting hours and hours being a slow learner ;-)


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## Paddy Enfield Dock (5 mo ago)

Truesolutions said:


> Im looking at them for Landrover and small trucks, but this one planned for my boat
> Lots of space, we did test with Leaf battery but lacked the range.


I am curious to know if you have had any success with this. I am currently researching the feasibility of using a model 3 pack to drive a Leaf motor for an inboard boat motor


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## Truesolutions (Mar 14, 2018)

Paddy Enfield Dock said:


> I am curious to know if you have had any success with this. I am currently researching the feasibility of using a model 3 pack to drive a Leaf motor for an inboard boat motor


Still working on it, need a board that can connect to the isoSPI coms that come out of it
Have to order or make somthing then connect that to a teensy to get info out to see what have to work with


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## Paddy Enfield Dock (5 mo ago)

Is this any use? 





Tesla Model 3 BMS Controller


Electric Vehicle (EV) conversions of BMW cars and related technologies.



www.evbmw.com


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## Truesolutions (Mar 14, 2018)

Paddy Enfield Dock said:


> Is this any use?


If he was selling them then, then would be of been good start but you also need to solder on the 'batman" chip
Don't have tools or skills to solder 120+ chip on to board


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## ElpacRovi (4 mo ago)

Hi all, first post in this forum and I'm sorry to say I will be exposing my lack of knowledge of all things involving IC's and my general naivety when it comes to finding a simple solution in today's complicated electronics world but here goes ...

I acquired a Model 3 AWD LR complete battery bank a few months ago showing 355v at the main terminals in the Penthouse. I intend to use it as a 'powerwall' as we get 3 or 4 power cuts a year some lasting a couple of days because we are at the end of an overground domestic supply that is susceptible to disruption. A 13kW powerwall just won't cut it. I've only just found this thread having searched the Internet high and low in my spare time for a couple of months but cannot find anything definitive on charging the battery pack out of a car. What I have found always relates to using a battery pack in a different car. I approached a couple of manufacturers of controller hacks but they advised it may not work because I wouldn't be applying sufficient load. So I would like to ask some questions if I may hoping not to run out of goodwill! 

My first question is ... do I need to have a 12v battery attached to the terminals? I have tried but it didn't seem to make any difference, I still couldn't apply a charge using a charge port cable and the white box charge controller supplied by a 3 pin mobile power cable duly hacked to think it was connected to a car! 

Is the operation of the Tesla BMS self-contained within the battery pack/penthouse or does it need something from elsewhere in the car? I found one post saying that is 'could' work in isolation but that wasn't 100% definitive and not supported by follow-up posts. If I cannot get the penthouse to agree to charge I wonder if I charged the modules direct with 400vDC would the Tesla BMS balance the individual 46 cell parallel blocks?

If not could I remove the Tesla BMS boards and solder in 3rd party BMS boards using the same connections and charge/discharge through the new BMS?

Also to reconfigure the 4 main modules in parallel so producing a c.100vDC bank would have advantages of bringing it into line with the 96v standard (but this would probably bring the chance of using the Tesla BMS to below zero! 

As I said this is not really your street but i would appreciate any thoughts and knowledge you may like to share.


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## floydr (Jun 21, 2021)

Head over to Second Life Storage & Solar There are a few powerwallers with complete and partial tesla automobile battery packs used as a backup source of power there. They may be able to answer your question better. another place to ask is DIY Powerwalls | Facebook the sister group to the secondlifestorage forum.
later floyd


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## ElpacRovi (4 mo ago)

floydr said:


> Head over to Second Life Storage & Solar There are a few powerwallers with complete and partial tesla automobile battery packs used as a backup source of power there. They may be able to answer your question better. another place to ask is DIY Powerwalls | Facebook the sister group to the secondlifestorage forum.
> later floyd


Thanks Floyd, will do


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