Tesla Model 3 Rear Drive Unit Hacking

[Kevin Sharpe]

Thanks to everyones help I have now got the prius gen 2 mg2 spinning beautifully with foc using the V1c board in a gen3 inverter.

That's very cool

[Jack Bauer]

Some info on the motor from a youtube comment (obviously elon under a pseudonym) :

Hope this help: The rear model 3 motor is a 6 pole permanent magnet motor. The rotor has 4 sub stacks, Each end sub stack is skewed by 3.33 degrees in relation to the middle 2 stacks which are matched to each other. The resolver is a 3 pole resolver.

[mdrobnak]

Some info on the motor from a youtube comment (obviously elon under a pseudonym) :

Hope this help: The rear model 3 motor is a 6 pole permanent magnet motor. The rotor has 4 sub stacks, Each end sub stack is skewed by 3.33 degrees in relation to the middle 2 stacks which are matched to each other. The resolver is a 3 pole resolver.

That sounds like a fairly unique setup?

[Jack Bauer]

I never thought I'd use the phrase" runs on the smell of a rag" with an electric motor but it applies to the M3 drive unit. Just needs to see a battery and it wants to run.

[Kevin Sharpe]

Congratulations!

[mike77cos]

Congratulations and well done

[Jack Bauer]

Thanks. Parameter file attached from today's run for the curious.

[JaniK]

It`s alive! GREAT JOB!

[Jack Bauer]

Don't suppose anyone knows what oil the m3 rdu needs? Dexron 6?

[Kevin Sharpe]

Don't suppose anyone knows what oil the m3 rdu needs? Dexron 6?

TMC says (here): The model 3 service guide calls the drive unit fluid "ATF-9". This does not appear to be a commercially available product. The exact description of the fluid is "ATF-9. SK Lubricant 422313 (part number 1135241-00-A)"

Edit: "ATF-9" also listed in a Model 3 RDU Service Bulletin (here)

Edit 2: "ZIC ATF - 9" details are on page 6 of the EPA certificate of conformity (here)

Edit 3: SK ZIC Oil don't list the product but some of the DEXRON VI parameters look close (here)

Edit 4: Page 5 of the Model 3 AWD EPA certificate of conformity also lists the front motor (here)

[JaniK]

Don't suppose anyone knows what oil the m3 rdu needs? Dexron 6?

TMC says (here): The model 3 service guide calls the drive unit fluid "ATF-9". This does not appear to be a commercially available product. The exact description of the fluid is "ATF-9. SK Lubricant 422313 (part number 1135241-00-A)"

Edit: "ATF-9" also listed in a Model 3 RDU Service Bulletin (here)

Edit 2: "ZIC ATF - 9" details are on page 6 of the EPA certificate of conformity (here)

Screenshot 2020-06-04 at 16.43.57.png

Way to go Kevin !

Google offers a MB approved list that has ZIC ATF 914 in the list with other atf approved my MB, https://bevo.mercedes-benz.com/bevolist ... 14_en.html

Is it the same?

[Kevin Sharpe]

Way to go Kevin !

No problem

Google offers a MB approved list that has ZIC ATF 914 in the list with other atf approved my MB, https://bevo.mercedes-benz.com/bevolist ... 14_en.html

Is it the same?

I can't track down the specs or a source for the "ATF 9" used by Tesla and can't answer your question

All I can say is that at 100 °C the viscosity is similar if the EPA documents are correct;

"ATF 9" = 5.9 cSt

DEXRON 6 = 6.16 cSt

I've attached the ZIC ATF DEXRON 6 data for reference (source here).

[Jack Bauer]

Close enough for me:)

[Kevin Sharpe]

Close enough for me:)

[JaniK]

I think I will use this, it is actually the only stuff available on the shelf at 33km from my home.

https://mag1.com/products/transmission- ... ion-fluid/

Viscosity @ 100°C cSt
ASTM D445
5.797

Cost: 10,56€/litre

[mike77cos]

Some oil is better than no oil at all

[celeron55]

I'd steer away from anything not clearly designed for hybrid transmissions, as the HV motor coils are definitely something that wasn't present when previous ATFs were designed and old ATFs might eat your coils or conduct electricity into the transmission case.

I think for example Toyota has got this covered since the early 2000s in their WS type oil that they use in lots of things.

Of course I have no idea what I'm talking about but that just makes sense to me, for the bare minimum requirement if you just want to buy the cheapest local stuff that might work.

EDIT: Actually, is the model 3 drive unit motor sealed from the transmission or not? I haven't been paying attention...

[JaniK]

Well, I still have lot of other stuff to do, so I can wait weeks to get "right" oil, and you got a good point there. And its not about saving maybe tens of euros here. Right oil Will last years and save thousands on not ruining the motor.

[Jack Bauer]

Time for a little update on the Model 3 drive unit.

Modchip board has been tested on the bench and works fine. Next up is wiring it to the inverter, then will need Johannes to do a few firmware mods to trigger the gate drivers at the right time during power up. As we saw from the Prius inverter tests the FOC firmware runs the motor just fine.

We'll do some high speed / high voltage runs to confirm functionality over the next week at which time the boards will go on beta release. A very long and boring video detailing the installation is in progress and will be released at the same time.

PDFs of the schematic and PCB will be available on github at that time however design source files will be available to Patrons only.

[JaniK]

I like that modchip design. Looking forward for the long and boring video

What did you do with the oil?

[jap]

Some oil is better than no oil at all

Nope, some VAG DSG gearboxes for example had a recall due to oil additives causinng burned control boards inside the box. So electronics and oils dont always mix well.

[PacEmaker]

I know you might not agree with this Damien but I'm gonna throw it out there anyhow:

I wholeheartedly endorse your approach to release of design source files to your Patreon patrons only.

As for firmware, I believe that should be released to Johannes' Patreon patrons only.

In other words, I think that everyone who supports Damien on Patreon should be supporting Johannes on Patreon as well.

Without firmware, the hardware is junk (beautiful junk of course). There, my tuppence-worth.

[JaniK]

It appears something came up, or are updates for patron only?

Did you manage to find time to test it yet?

[Jack Bauer]

What came up is I'm one person juggling 50 projects. The modboard design is done. The inverter is reverse engineered. Openinverter FOC firmware runs the motor so all is left is wiring the modboard to the inverter and putting the drive unit back together. I'll get to it when I get to it.

Patrons get early access but everything will be published here.

[JaniK]

Now I feel silly asking the obvius, I know you have your hands full. Can I help somehow? I have one m3 rear driveunit here.