Thanks Tom. I do have a coder guy who has been helping me, but we only recently realized that things might nOt actually be as they seem with the BMS, so he hasnt really looked in to it yet. Is the code on the GitHub the most up to date for him to investigate? It looks like latest release .03 but ...

I noticed the software version on mine is a .07TA on this but the latest release I saw on the Github is 0.03. Is the newer version also posted somewhere?

Is there any other beta testing I can do, or troubleshooting to try and see if my balancing issue is a HW or SW issue? Thanks

CHAdeMO communication is all CAN, so you could make it work with CANDue, but again, you're going to have to find and piece together the code for that. I'm also not sure how many different things you can get the CANDue to handle. That'd be some more advanced coding than I'm comfortable with, but if ...

I made a quick chart of voltages u1-u96 to better visualize what's happening:

Thanks for the Info Tom. Can you clarify about the SOC calculation? It seems like in your last 2 posts here you said the BMBs do not calculate SOC and also the firmware does not calculate SOC. I am guessing the SOC would be calculated like (udc-dischargeVlim)/ (chargeVlim- dischargeVlim), correct ...

Yes the balancing current is like 40mA so very very slow.



It is not



Depends on where in the voltage curve you are.


Thanks for the reply and info Tom! So does that mean soc is calculated by the BMB's and then reported to the BMS unit? How should the BalVthresh parameter be set or managed ...

How is state of charge calculated in this firmware? I am noticing large swings in soc with small changes in pack voltage. Seems to be maybe dependent on deltaV (higher deltaV ==> lower soc) but not sure.

I got the following info from someone with a Model3, for reference: 78% @ 390V; 62% @ 373V; 37 ...

I have been doing a little bit of test driving, a little bit of charging and attempting to get my cells balanced. Right now I'm seeing 84 out of 96 cells are balancing, and so the deltaV was getting strangely high as a result.

Charging the battery seemed to help decrease deltaV substantially. Also ...

Would you want to use this in a car? If so, can’t you just use the power split device of a Toyota transmission to achieve what you want?

Couple an ICE engine with a governor to the bell housing, and start it. Now, apply regen to MG1 via some input like a potentiometer on a dial. You are now ...

I am curious about building a hybrid system with a configurable AC generator (15-18kW), a 3phase motor (auxiliary motor, NOT a traction motor), and a battery pack.

Would the Toyota / Lexus inverters with their dual A/C connections be a good choice for this design? I believe each unit actually ...

Thanks for the info Manglesdorf! I know the Zombieverter would probably make this process a bit easier, but I already have the CANdue, plus I think their shipping to US might be currently suspended, plus the zombieverter has a lot more capability (and price) than what I need. I am not sure if the ...

My build is so close to completion but I'm a little lost! I am working on building the CANbus and configuring the 'brains' of my vehicle but not sure the steps of the procedure.

Items to be on the CANbus:
Tesla LDU with OpenInverter board
Ovartech 6.6kw charger & DC/DC conv.
IVT-S Shunt
EVTV CANDue ...

Thanks Tom!

Anyone having success getting the balance function to work on 1+ modules?

I have a salvaged j1772 inlet connector from a nissan leaf and was trying to figure out which wire from the harness was prox and pilot. Couldnt find any continuity until i took it apart and behold! The prox and pilot pins do not connect to anything beyond a few inches past the inlet! The two pins on ...

Hello all,

I'm trying to source a Tesla Model 3 23s BMB for troubleshooting purposes. The openinverter BMS controller works fine with 25s modules but seems to have an issue with 23s modules. Unfortunately my build is without a fully functional BMS until resolved.

I'm trying to get Tom a 23s BMB so ...

Bratitude wrote: ↑Mon Mar 24, 2025 8:27 pm I have a contact on Facebook with bmb boards (you emailed me I’m guessing?) I’ll he’s on the ev conversion group as well. Ill message you with his contact

Thanks! Yea please send me his info! Any luck with your BMS controller Brat? I think youre using the shortest Model3 modules, correct?

Damien’s ongoing truck build inspired me to get back on the forum and share my similar build! Long overdue update:

Drivetrain complete with modified LDU and custom driveshafts, and hopefully strong enough

All four Model 3 modules individually reboxed and installed

Openinverter model 3 BMS ...

Just emailed them over Tom, thanks.

Can you please try just one of the modules. It is over a year since I worked on the M3 BMS, looking at the notes we tested it on a full pack with 24s modules.


Hi Tom, I have not yet bussed the modules together and so far have connected the BMS controller individually to both of the short ...

Does anyone know what kind of connector is used between the BMB slave cards? Its the purple connector between the modules. I have the T2C controller with the BMS option. The modules are in a custom box, so I need lengthened cables.

Looks like there are vias on those circuits that I could tap into ...

Thanks for the guides and I found couple of more instruction how to get that up and running again. I am back with a working board and now are scratching my head about the situation that only 88 Cells are reported instead of the 96. The total Batery voltage divided throught the measured average ...

The Tesla gearbox is 4.5:1 IIRC

I swapped the diffs to 3.42 lsd and I have 31” tires but will likely end up moving to 3.08s and possibly larger tires to further increase my top speed and ,more importantly, slow down the motor cruising at hwy speeds

Who’s got thoughts on mounting and BMS’ing the Model 3 modules? I really liked what SuperfastMatt did with his swap. My layout of the batteries in the vehicle will be very similar, but my current design has each module individually boxed. One problem I have is I didn’t buy the whole pack, so I dont ...

are you going to get a plunging rear drive shaft made with a support bearing?


Yes, that’s the idea, a two-piece rear driveshaft with a carrier bearing mounted to the crossmember behind the LDU. The longer, rear section of the driveshaft will need a plunge or telescopic bit due to the solid axle ...

As for the remainder of the build, I've Quaifed all over the LDU with new gearing and LSD, plus the trusty openinverter controller. I've got a prius accel pedal installed and prius power steering (not yet installed). I got driveshaft adapters made at the machine shop as you can see in the pics, but ...