GM / Chevrolet Volt Gen2 DC-DC converter

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GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

Searching for a compact watercooled DC-DC converter I came across the GM Volt Gen2 DC-DC converter.
Bought one at Ebay and just figured some things out:

HV-connector: DELPHI / APTIV 33107347
Signal connector: JST ATSSPB-C0802Y-1AK

Signal connector pinout:
Pin1 = Voltage setpoint -> PWM 10...90%. >10% starts converter, default 13,80V. 70-90% gives 13,80V...15,00V
Pin2 = NC
Pin3 = Converter status -> 10% = In operation. 70% = HV present, no voltage setpoint
Pin4 = NC
Pin5 = +5V supply, limited at 30mA. Not used by GM
Pin6 = +5V input, internally pulled high. Not used by GM
Pin7 = NC
Pin8 = NC

Found the current limits below:
- HV limit: 343V / 7,0A = 2400W
- Output limit: 12.2V / 168A = 2050W (inaccurate measurement, converter limiting)

So it seems to be specced at around 2400W / 14V 150A
Unfortunately no onboard CAN for extensive diagnostics (temperatures, voltages, currents), but a simple & compact unit when you have something available to generate the PWM setpoint signal.
IMG_0014.JPG
IMG_0012.JPG
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by Thatguyoverthere »

If anyone is looking on ebay, they're going for about <$150, under the part number -- 24280796 --.
https://github.com/kaelinwilson
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

They are indeed very cheap compared to e.g. the Tesla DC-DC's which start in Europe on Ebay at €500.

I found some GM Service bulletins; there will probably be several part nr's around:
2016 model: 24275451 -> 24277705 -> 24283105 -> 24286781
2017-2018 model: 24281923 -> 24286781
2019 model: 24277908 -> 24296191

The one I tested is a 24284603 / MSE718B. Just saw one on Ebay USA for <$100
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by DarkwingDuck »

Nice find! Thanks for sharing. Just bought a 24284603 for my conversion. Although I think the other part no's you mentioned are for charging the HV pack? If I look up those part no's I get units with what looks like a 2-pin connector for HVDC and one 4-pin connector for (presumably) AC and proximity? No "standard" +12V connector to be seen.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

FJ3422 wrote: Sat Aug 22, 2020 5:39 pm They are indeed very cheap compared to e.g. the Tesla DC-DC's which start in Europe on Ebay at €500.

I found some GM Service bulletins; there will probably be several part nr's around:
2016 model: 24275451 -> 24277705 -> 24283105 -> 24286781
2017-2018 model: 24281923 -> 24286781
2019 model: 24277908 -> 24296191

The one I tested is a 24284603 / MSE718B. Just saw one on Ebay USA for <$100
I dont mean to sound too corrective, but all of the above numbers are for Chevy Volt II charger not DCDC.
24284603 is the actual DCDC converter.

I dont see why we couldnt get to know the 3kW charger though. From here i saw it is also pwm controlled unit.
https://www.diyelectriccar.com/threads/ ... ost-972625
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

arber333 wrote: Tue Aug 25, 2020 9:06 am I dont mean to sound too corrective, but all of the above numbers are for Chevy Volt II charger not DCDC.
24284603 is the actual DCDC converter.
You are completely right; swapped the DC-DC & charger numbers.
Tested the Volt gen2 charger as well (check the picture of the workbench, below the DC-DC). Nice compact unit, charges at max. 3,6kW (230V 16A). Outputs ACvoltage & HVdc voltages as a 100Hz PWM signal, and limits the AC current according to a PWM signal setpoint. I don’t know if scaling of the setpoint is already known, if not I will post it here.
Drawback of the Volt Gen2 charger is that you will need an additional controller for the EVSE communication, pilot signal cannot be wired directly to the charger.

Some other chargers do have this onboard (e.g. Mitsu Outlander, can also see it on my workbench). Still looking around for an affordable BMW KLE charger to test, this is as compact as the Volt charger, and has pilot communication onboard according to the BMW wiring diagrams.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

Hm... Damien, Isaac, could Chademo (LEAF) VCU take care of 2x analog pwm signal for DCDC and volt ii charger 😊?
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by Isaac96 »

arber333 wrote: Tue Aug 25, 2020 3:54 pm Hm... Damien, Isaac, could Chademo (LEAF) VCU take care of 2x analog pwm signal for DCDC and volt ii charger 😊?
Maybe next week. Certainly possible, but we still don't have CHAdeMO tested.
@FJ3422 has the DC/DC signals all working, if someone could do the same for the charger I'll think about adding VCU functionality.


-Isaac
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

Isaac96 wrote: Tue Aug 25, 2020 4:08 pm
Maybe next week. Certainly possible, but we still don't have CHAdeMO tested.
@FJ3422 has the DC/DC signals all working, if someone could do the same for the charger I'll think about adding VCU functionality.

-Isaac
OK, I haven't considered we could be using Chademo functionality in parallel with EVSE charging, just the VCU with alternative code.
But if we could use CAN, PWM transmit and Chademo with the same VCU that would be really awesome.

Tnx
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by Kevin Sharpe »

arber333 wrote: Tue Aug 25, 2020 4:55 pm
Isaac96 wrote: Tue Aug 25, 2020 4:08 pm
Maybe next week. Certainly possible, but we still don't have CHAdeMO tested.
@FJ3422 has the DC/DC signals all working, if someone could do the same for the charger I'll think about adding VCU functionality.

-Isaac
OK, I haven't considered we could be using Chademo functionality in parallel with EVSE charging, just the VCU with alternative code.
But if we could use CAN, PWM transmit and Chademo with the same VCU that would be really awesome.

Tnx
Lets keep this thread focused on the Volt Gen2 DC-DC and I think it's worth posting this once again;
Jack Bauer wrote: Wed Aug 19, 2020 6:49 am Folks please at this point no modifications. Once we have one system proven to work everyone will be free to fork it off and make their own version.
This is a personal post and I disclaim all responsibility for any loss or damage which any person may suffer from reliance on the information and material in this post or any opinion, conclusion or recommendation in the information and material.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

@ FJ3422

Can you try giving Pin1 either 3V3 or 5V signal. I am curious if it really needs PWM control or is its input just RC filtered and used as analog voltage detection.

tnx
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by ggeter »

Bump -- was this tried? If not, excuse my ignorance, what would be the PWM signal? 5v on/off for x cycles per second? This is a great little unit and would love to use if I could get it to work easily.
arber333 wrote: Thu Sep 17, 2020 12:43 pm @ FJ3422

Can you try giving Pin1 either 3V3 or 5V signal. I am curious if it really needs PWM control or is its input just RC filtered and used as analog voltage detection.

tnx
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

I currently do not have a batterypack ready for testing (so no decent HV source), but will test it as soon as I have !

If you are looking for a simple PWM-source, search for "NE555 PWM board' or something similar. e.g. at Aliexpress for < 1$.
NE555-board.jpg
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

FJ3422 wrote: Tue Dec 01, 2020 7:32 am I currently do not have a batterypack ready for testing (so no decent HV source), but will test it as soon as I have !

If you are looking for a simple PWM-source, search for "NE555 PWM board' or something similar. e.g. at Aliexpress for < 1$.
No, my question was if it is possible to start DCDC with only a voltage function, not 1kHz PWM. In that case it would be super easy to use one voltage converter 12V - 5V on pin 1.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

FJ3422 wrote: Tue Aug 25, 2020 3:18 pm You are completely right; swapped the DC-DC & charger numbers.
Tested the Volt gen2 charger as well (check the picture of the workbench, below the DC-DC). Nice compact unit, charges at max. 3,6kW (230V 16A). Outputs ACvoltage & HVdc voltages as a 100Hz PWM signal, and limits the AC current according to a PWM signal setpoint. I don’t know if scaling of the setpoint is already known, if not I will post it here.
Drawback of the Volt Gen2 charger is that you will need an additional controller for the EVSE communication, pilot signal cannot be wired directly to the charger.

Some other chargers do have this onboard (e.g. Mitsu Outlander, can also see it on my workbench). Still looking around for an affordable BMW KLE charger to test, this is as compact as the Volt charger, and has pilot communication onboard according to the BMW wiring diagrams.
Hi

I just got one of those Gen2 DCDC units. Looks good.
Can you tell me which pins of the HV connectors are HV+ and HV-? I dont want to break the seal.
Please use connector as reference. On one side it has two notches and on the other only one.

I ordered HV connector from Mouser Aptiv P/N 33107347
I also got pins P/N 15446674
Only connector is not enough. You need to get the end cap P/N 13824779 with rubber seal P/N 15513451. Seal is not easy to get. I imagine i could use silicon glue to seal the cable in. As it was i had some HV connectors left from Ampera/Volt Gen1 and looks like endcap with seal is compatible.

Also i got LV connector JST P/N ATSSPB-C0805H-1AK
I also got pins P/N SAIT-A03T-M064

Both connectors are available in single quantity and they fit and lock good!

tnx

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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

Never mind.. i found quick test procedure here:
viewtopic.php?p=8215#p8215

When i tested i found out HV NEGATIVE is on the side of TWO notches and HV POSITIVE side has only ONE notch.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

That's right. From the GM documentation:
GM DCDC-HVconn.PNG
GM_HV-Overv.PNG
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

OK... my DCDC doesnt want to start 14V! When i connect 360Vdc i get 70% duty signal on pin 3. But when i show it 75% duty 12V pwm signal to pin 1 i get no reaction. Did you connect 12V battery or just the load?

tnx
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

Hi... i tried to start my DCDC and when i connect 360Vdc i get 70% PWM on pin 3. So far is good. Then i apply 12V 75% PWM to pin 1 and ...nothing!
No change in pin 3 and no 14V source. What kind of PWM signal you used? I tried 70% from 100Hz to 1000kHz...
Do i have to connect something else? Did you actually connect 12V battery?

EDIT: I figured pin 1 has some pulldown and when i gave it 12V via transistor i got 5V on the pin. I replaced pullup resistor on my transistor to 330R and i get good 12V signal... and still no start.

tnx
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

arber333 wrote: Sat Mar 20, 2021 7:48 pm Did you connect 12V battery or just the load?
Yes I connected a small battery on the output. That might probably be needed to let it start.
I can't remember the PWM frequency, but I used the same as on the output (which you can measure). Given the fact that the charger uses 100Hz, I guess the DCDC also takes 100Hz.
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

FJ3422 wrote: Sun Mar 21, 2021 8:13 am Yes I connected a small battery on the output. That might probably be needed to let it start.
I can't remember the PWM frequency, but I used the same as on the output (which you can measure). Given the fact that the charger uses 100Hz, I guess the DCDC also takes 100Hz.
Yes but still i cant get it to start!

I have 12V battery connected. I connect 370Vdc to main connector. Then i verify LV connector pin3 is at 70% PWM. Then i use my signal generator and connect it to IRF510 Mosfet and i use 330R pullup to signal 75% PWM on Pin1. Nothing...!

Next i went and took apart DCDC. I found a small control board and connector where PWM signal enters the board. If i trace PWM along i eventually come to a transistor. There signal goes into its base/gate and it seems nothing of value is transmitted out of transistor.
Would it be possible for you to send me a photo of your PWM signal and signal generator setup?
Also do you think you could take the cover plate off and measure what kind of signal comes out of that transistor?


EDIT: Schratch that! I went by the 12V power route and immediately i found out that directly behind the main power stud there was no 13V and it was immediately behind the plastic separator. And i thought it was separator. Probably it is a fused link and in my case it burned out!
Now that i went on and connected 12V battery directly to output link behind the casing and feed 110Hz 120Hz 50% duty PWM DCDC came alive. I got 13.6Vdc. It works from 110Hz 120Hz to 140Hz.
Also i noticed that if i would remove the signal at that point DCDC would keep providing power regardless the signal.

Then i tried to provide various PWM duty at 110Hz 120Hz. Those values are under light load with 12V battery attached.
70% ........14.2V
67% ........14V
63% ........13.8V

I will try to provide more load when i solve the problem with the fuse...

EDIT: I just couldnt resist and i quickly connected my 1kW load of 9 H4 light bulbs directly to the output. I could measure 14V at 74A = 1kW!

EDIT2: Well ill be...!! :twisted: That plug has base plate that is connected to internal contact but M8 stud itself is NOT! Since i did not connect this directly to the plate my contact was weak or no contact at all. Of course DCDC sensed there was no 12V battery connected and it wouldnt work.

EDIT3: I can now confirm DCDC can actually work with 5V PWM signal...
I also found out signal works down to 45% duty where DCDC actually stops. It will be interesting to setup my DUE for 70% PWM output on ENABLE signal and 30% PWM when signal is not present to keep DCDC off.

I can now assume everything is good and my DCDC works as it should.

A
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

Johannes, can you please transfer this thread under Chevy/Opel/Vauxhall/PSA section?

Thanks! :D
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

I tried to drive this DCDC with 407Vdc from 104S battey and it works! It bloody works!
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by arber333 »

FJ3422 wrote: Sun Mar 21, 2021 8:13 am Yes I connected a small battery on the output. That might probably be needed to let it start.
I can't remember the PWM frequency, but I used the same as on the output (which you can measure). Given the fact that the charger uses 100Hz, I guess the DCDC also takes 100Hz.
Hi i have a question again. This Volt Gen2 DCDC will not stop. As soon as i provide PWM it will start at 14.2Vdc. But if i remove PWM signal it will drop to around 13.6Vdc and stay there indefinitely. While i tried to vary PWM i gave it 40% duty and it stopped. But if i would remove PWM it would revert back to 13.6Vdc.

Can you confirm that? Is anyone using this DCDC with or without contactor and had similar observation?
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Re: GM / Chevrolet Volt Gen2 DC-DC converter

Post by FJ3422 »

arber333 wrote: Sat Oct 09, 2021 12:29 pm
FJ3422 wrote: Sun Mar 21, 2021 8:13 am Yes I connected a small battery on the output. That might probably be needed to let it start.
I can't remember the PWM frequency, but I used the same as on the output (which you can measure). Given the fact that the charger uses 100Hz, I guess the DCDC also takes 100Hz.
Hi i have a question again. This Volt Gen2 DCDC will not stop. As soon as i provide PWM it will start at 14.2Vdc. But if i remove PWM signal it will drop to around 13.6Vdc and stay there indefinitely. While i tried to vary PWM i gave it 40% duty and it stopped. But if i would remove PWM it would revert back to 13.6Vdc.
Can you confirm that? Is anyone using this DCDC with or without contactor and had similar observation?
I don't have a battery set-up to do a quick bench test again; but what I noted back then:

Code: Select all

Pin1 = Voltage setpoint -> PWM 10...90%  
			-> >10% starts converter, default 13,80V
			-> 70-90% gives 13,80V...15,00V
Pin2 = NC
Pin3 = Status           -> 10% = In operation
			-> 70% = HV ready, no voltage setpoint
Pin4 = NC
Pin5 = +5V supply, limited at 30mA. Not used by GM
Pin6 = +5V input, internally pulled high. Not used by GM
Pin7 = NC
Pin8 = NC

Was it really working at 13.6V ? Did you have a small load (resistor) connected at that moment ? If so, you can give it a try to connect pin 6 to GND. Maybe that's an enable ? Or maybe it needs a PWM of <10% for a moment to shutoff ?
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