# Tesla DC DC Converter Hacking



## jackbauer (Jan 12, 2008)

I had a strange dream last night involving a Dragon capsule landing in my back garden. I have takes that as a sign to do some more Tesla hacking. Behold the Gen 2 DC DC converter. Looks like a simple beast but very nicely made.

We'll need to do CAN control as there is no separate logic board for me to replace (boooo). Anyway, here is a look inside to get things moving. As usual, all material will be open source and I'll set up a Github repo once I get some things happening.


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## piotrsko (Dec 9, 2007)

Nice of them to mark comm pins.

Hmmm. Delta controls. Wonder if they use BACNET protocols


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## CKidder (Dec 12, 2009)

Seems like not too many people were interested in this. But, I am. A good DC/DC converter is necessary for any EV project and it seems like an often overlooked item. It might be a blessing in disguise that there's no board to replace. It really is more convenient if you can use the existing board if at all possible. That hasn't been fun for the chargers and inverters but I think the DC/DC is probably simple enough that it should work and would allow them to be used as-is. That's a win for everyone.


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## john61ct (Feb 25, 2017)

Yes, treating a commercial EV pack as much as possible as a black box system, 

native charging and all

then a simple buck conversion for consumer loads

seems ideal to me. 

Someone who could do this for 12-14V range output, maybe at max 200A per pack, with user-friendly limiting

at a reasonable price would find a good market IMO in the camping / van dwelling / expedition arena, maybe even marine market once proven safe

both for turnkey House banks and DIYers who can find their own packs


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## kennybobby (Aug 10, 2012)

Does it have a rectifier bridge on the front end under that white card? It might work DC or AC, since it looks like a EMI filter network at the upper edge from the fuse to the white cover. Is there an interlock switch inside the blue connector?

OTP pad = One time program? What is the microcontroller--maybe just solder on a blank one and roll your own code.

what traffic do you see on the TxRx? i think Collin is right, looks like you will slam dunk this one with the original board.


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## Kevin Sharpe (Jul 4, 2011)

some useful info on the DCDC in this thread 

Hacking the Tesla Main Junction Box


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## golfdubcrazy (Dec 19, 2014)

Hi i know this is an old thread, but just a quick one. do you only need to supply this unit with a 12v enable signal to start the DC/DC converter ? and i then assume it self regulates ?


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## kennybobby (Aug 10, 2012)

No you need CAN buss commands to operate it, did you not read the thread, did you not check out the link that Kevin posted?


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## Bry5on (Mar 14, 2016)

Based on the other thread linked above by Kevin, you do only need to supply 12v enable and ground to get this DC-DC to work.


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## kennybobby (Aug 10, 2012)

The Gen2 unit may come ON with the 12V Enable, but it still needs CAN buss to operate it and change the output voltage.


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## Bry5on (Mar 14, 2016)

13.5 seems like a good voltage to run constantly, I don’t see why you’d need to change it with CAN to use it. Maybe I’m missing a critical detail but it looks like its default voltage is just fine to me.


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## Bry5on (Mar 14, 2016)

Installed and got mine running this evening. At first pass it seems to auto-ramp the voltage based on demanded load. I was seeing about .5-.7V more after turning on headlights, high beams and heated seats in my conversion car.

I wasn’t measuring coolant temp rise but after 45 minutes with all of the above and the stereo on loudly, drawing close to 1000W total (back calculated from my HV pack BMS), I couldn’t tell a difference in coolant temp from ambient with my fingers, which are not exactly a calibrated instrument.

Super happy with this! Sure beats the previous meanwell converter.


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## kennybobby (Aug 10, 2012)

Bry5on said:


> Installed and got mine running this evening. At first pass it seems to auto-ramp the voltage based on demanded load. I was seeing about .5-.7V more after turning on headlights, high beams and heated seats in my conversion car.
> 
> I wasn’t measuring coolant temp rise but after 45 minutes with all of the above and the stereo on loudly, drawing close to 1000W total (back calculated from my HV pack BMS), I couldn’t tell a difference in coolant temp from ambient with my fingers, which are not exactly a calibrated instrument.
> 
> Super happy with this! Sure beats the previous meanwell converter.


That is great to hear, thanks for sharing your experience.

The pages of the myleaf forum are littered with thousands of postings of problems and issues caused by a weak 12V aux battery; most of this seems to be premature failure due to sulfation. 

The leaf dc/dc profile goes up the 14.4 for a brief couple of minutes after starting, then drops and holds at 13.2VDC. 18 to 36 months of this cycle results in a sulfated aux that no longer performs as needed.


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## fzmohsen (May 28, 2020)

jackbauer said:


> I had a strange dream last night involving a Dragon capsule landing in my back garden. I have takes that as a sign to do some more Tesla hacking. Behold the Gen 2 DC DC converter. Looks like a simple beast but very nicely made.
> 
> We'll need to do CAN control as there is no separate logic board for me to replace (boooo). Anyway, here is a look inside to get things moving. As usual, all material will be open source and I'll set up a Github repo once I get some things happening.


Hi...
Thanks for sharing these images.
I found that there is a boost interleaved converter before the main phase-shifted full-bridge dc-dc converter...
can you explain what is the role of the boost interleaved converter?? and what criteria induce the tesla to implement the interleaved boost converter before the PSFB?
and another question
why there are three chokes? usually, we use two chokes in EMI filters..
Best Regards....


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## kennybobby (Aug 10, 2012)

Do you have a sketch or diagram of the circuit--i would have guessed this was after the FBR and used for PFC (Power Factor Correction). 

Where are the 3 chokes you refer? Again a diagram is really needed to discuss anything.


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## fz mohsen (Jul 13, 2020)

That is a dc-dc converter, not an ac-dc converter, therefore, there is no need for PFC
About the chokes, please look at the input side. there are three chokes
two upright chokes which are used for conventional EMI filters
and a recumbent choke right after the input port ( what is the role of this choke?) 
about the digram, I am certain there is a PSFB converter which suggested by TI


https://www.ti.com/tool/TIDM-PSFB-DCDC#descriptionArea


But I don't know why Tesla uses a boost interleaved converter before the PSFB...
For what purposes...


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## MattsAwesomeStuff (Aug 10, 2017)

Just FYI, Jack Bauer no longer participates in this community, after it's ownership caused the loss of much information and the community has no control over it anymore.

You can find him (Damien) over on the OpenInverter forum.

However, he's also stopped supporting Telsa S/X stuff. I won't put words in his mouth, but people using Tesla parts tend to be performance minded and borderline demanding/rude with their expectations from a free project. He's in the process of reverse engineering the Model 3 BMS and controller, but my impression is that he never wants to touch S and X stuff again.

However the Prius Gen2 (maybe Gen3?) inverters have a braindead simple DC-DC converter that works from ~200v down to 12v. Literally just one control pin turns it on and you're good to go.


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