# Chevy volt and spark , location and specs DC to DC converter



## Markijohn (Feb 7, 2014)

aeroscott said:


> I'm trying to find the location in the cars and any information about them.


The Chevy Volt DC-DC is called the "APM" - Auxiliary Power Module. It is located in the trunk. I have one coming from the same car I got the pack out of. It uses CAN communication to wake it up to make it function. I have all the information on how to wake it up and make it function. It is very hardy and really doesn't need to be cooled via fans as long as it is in a location that gets adequate airflow. 

How do I know this? We used this in our hybrid vehicle for NC State University in the EcoCAR2 competition. I will need to talk to my controls guys to figure out what signals exactly were used to send the wake command, but it is very easy to do.

I'm sure I have specs on the APM somewhere as well, I'll have to dig them up. They may be proprietary, so I may not be able to post the full document.


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## aeroscott (Jan 5, 2008)

Thanks very much, looking forward to hearing more.


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## Markijohn (Feb 7, 2014)

As expected, I am not allowed to upload these documents. 

I can say, the APM is rated at 2.2kW under "normal inlet air temperature", derated only to 2.0kW under "elevated" temperature.

Temp range -40C to 95C

Rated input values - 260V min, 350V nom, 420V max.

Standard output 150A @ 13.5V

There is a TON more info on this data sheet, just not sure what all would be applicable to us as EV hobbyists.


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## Markijohn (Feb 7, 2014)

This is where we mounted it in our vehicle.


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## aeroscott (Jan 5, 2008)

Would it be possible to send as private message , without infringing on the proprietary nature . Thanks


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## Markijohn (Feb 7, 2014)

In fact, I got my APM in the mail today! Very excited.


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## aeroscott (Jan 5, 2008)

Looks great, what kind of price range have you seen on them .


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## Markijohn (Feb 7, 2014)

aeroscott said:


> Looks great, what kind of price range have you seen on them .


Check out this post from my other thread: http://www.diyelectriccar.com/forums/showpost.php?p=471449&postcount=12

Long story short, I got mine for free, so I'm not sure.

Using Car-Part.com, I think I saw they were asking like $600 for these. I'm not completely sure because I know it as the APM and they were calling it a converter, which of course, this is... so it is probably correct in assuming they really do want $600 for these.


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## aeroscott (Jan 5, 2008)

I was looking at your other post when you posted. Great deal.
might be motor inverter that they were referring to


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## Markijohn (Feb 7, 2014)

I sent you a PM earlier, not sure if you saw it.

What specific information are you looking for on the APM outside of the general specs I posted previously.


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## bjcouche (May 17, 2013)

I believe he and I are looking for the CAN bus commands necessary to turn it on and make it useful for something other than a boat anchor.

Brian


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## Markijohn (Feb 7, 2014)

bjcouche said:


> I believe he and I are looking for the CAN bus commands necessary to turn it on and make it useful for something other than a boat anchor.
> 
> Brian


Brian,
I am currently busy with other projects, I will be getting to my EV very soon, at which point I will figure out the CAN comm and let you guys in on how to get it to talk. I know it is literally just a wake signal you need to send it, possibly one or two other commands. I'll keep you updated when I get to it for sure.


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## esoneson (Sep 1, 2008)

Please forgive my ignorance. I had been planning on using a Volt battery pack in my BMW 318i conversion for a long time now. And now I see that it might be a good idea to also use the DC-DC converter (APM) too. So here is my question, is the APM a DC-DC converter AND a charger for the pack? If not what is the charger called so I can look it up on car-part.com. And is it 'decode-able' too?

Thanks.

Eric


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## Markijohn (Feb 7, 2014)

esoneson said:


> Please forgive my ignorance. I had been planning on using a Volt battery pack in my BMW 318i conversion for a long time now. And now I see that it might be a good idea to also use the DC-DC converter (APM) too. So here is my question, is the APM a DC-DC converter AND a charger for the pack? If not what is the charger called so I can look it up on car-part.com. And is it 'decode-able' too?
> 
> Thanks.
> 
> Eric


Eric - Nice to see another NC guy on here...

The APM is not a charger. It is a 2+kW DC-DC converter that takes the 400ish volts and gives you a 12V supply for your low voltage components (radio, controllers, etc). The charger is a completely different item located in the front of the car. As Brian just pointed out to me, usually gets smashed in the front end collisions that most of the battery packs are pulled from.

The APM is located in the trunk of the car. I have a picture of it in post 7 of this thread in case you missed it. I looked on car-part.com and the only thing I could see it being called was "converter", so I'm not sure if that is what it is. I would suggest calling whoever has the "converter" and ask them to take a picture of it and send it to you. You can compare it to my picture to be sure its the APM.


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## w.b.zimmer (Jul 24, 2018)

Has anyone figured out the CAN Bus Messaging for the volt DC/DC Converter? I know how to make these part numbers work 24262765 and 24261518. But they are no longer available and you can only get 24262768 Which I can't get to work any help would be greatly appreciated.


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## Junkwizard (Aug 27, 2018)

w.b.zimmer said:


> Has anyone figured out the CAN Bus Messaging for the volt DC/DC Converter? I know how to make these part numbers work 24262765 and 24261518. But they are no longer available and you can only get 24262768 Which I can't get to work any help would be greatly appreciated.


I can't find any information on any of these units besides vauge gestures towards canbus. Maybe we can use what you know of the older models to get all of them to work. Shoot me a PM.


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## x.l.r.8 (Oct 20, 2018)

Did any one obtain the Can bus messages to start the APM?? seems it died a death and I cant find anything


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## x.l.r.8 (Oct 20, 2018)

Found all the information as its well buried from 5 years ago. The important and I do mean important part is researching your APM model number. i deliberately went with the highest output one that as in most of EV conversions was the first one before they started cutting corners. 
The model to look for is MSE465D and MSE716, not MSE716S 
Once you have that you jsut need a can driver @500k 
ID - D0 - D1 
0X1D4 OxA0 0XB2 turns the output on, 
repetition rate 50ms keeps the set voltage, if can lost once on V=13.5

ID - D0 - D1 
0X1D4 0x00 0XB2 turns output off

Some can bus bytes are reversed when entering data to transmit so if it doesn't work then reverse the 2 bytes and start with D7 rather than D0.

All recognition goes to EVTV motor verks who simplified it for me after spending 2 days sifting through Can dumps and all the traffic from the GMLAN I stumbled across their information and the rest is history.


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## x.l.r.8 (Oct 20, 2018)




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## CanadaLT28 (Oct 15, 2011)

x.l.r.8 said:


> Found all the information as its well buried from 5 years ago. The important and I do mean important part is researching your APM model number. i deliberately went with the highest output one that as in most of EV conversions was the first one before they started cutting corners.
> The model to look for is MSE465D and MSE716, not MSE716S
> Once you have that you jsut need a can driver @500k
> ID - D0 - D1
> ...



I still haven't sorted which DC-DC I will be using with the leaf motors but I may use the Volt one as I have one available. I know absolutely zero about how to work with CANbus so would it be too difficult to make an arduino or some other circuit provide the wakeup and keep the thing working? If so, who could I pay to make one up for me (or provide a schematic for one so I can make it).


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## x.l.r.8 (Oct 20, 2018)

$30 for a can transmitter, program it to transmit the code. You can transmit every 50ms for preset voltage or if you just momentary turn it on it stays at 13.5v. That’s all there is to it. I’m sure there’s a can shield in arduino that would also work, or EVtv motor verks have a great can driver on a arduino board that would also do the rest of the system. There’s lots of options, best bet is decide on your whole system and then see what works. I deliberately chose everything on the 500k so it would be easier to organize.


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## x.l.r.8 (Oct 20, 2018)

Check the model number of your volt APM. I have to fire mine up, I have a habit of buying a redundant extras, I can tag a third on if needed.


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## rx7r3ev (Dec 11, 2018)

x.l.r.8 said:


> Found all the information as its well buried from 5 years ago. The important and I do mean important part is researching your APM model number. i deliberately went with the highest output one that as in most of EV conversions was the first one before they started cutting corners.
> The model to look for is MSE465D and MSE716, not MSE716S
> Once you have that you jsut need a can driver @500k
> ID - D0 - D1
> ...





I'm attempting to fire up the APM with an Arduino and a CAN BUS shield. I've sent the message to start it (ID 0X1D4; Byte[0] 0XA0; byte[1] 0XB2). 



I have the APM output connected to a drained battery with 4.68 volts on it. The input HV is coming from a Chevy Volt pack with 348VDC. 



On the serial monitor I'm receiving a message from the APM with a message ID of 470. A sample set of these messages looks like:


RECV[7] : ID 470 : 128 : 44 : 59 : 61 : 61 : 12 : 75
RECV[7] : ID 470 : 128 : 44 : 58 : 61 : 61 : 12 : 91
RECV[7] : ID 470 : 128 : 44 : 60 : 61 : 61 : 12 : 131
RECV[7] : ID 470 : 128 : 44 : 61 : 61 : 61 : 12 : 147
RECV[7] : ID 470 : 128 : 44 : 57 : 61 : 61 : 12 : 163
RECV[7] : ID 470 : 128 : 44 : 62 : 61 : 61 : 12 : 187


As observed the byte[2] and byte[6] are the one that changes.


I've measured the output to the battery and its stuck at 4.68 volts. Anyone have decoded what message ID 470 means? 



The APM doesn't seem to be sending the correct output voltage. Please help.


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## x.l.r.8 (Oct 20, 2018)

Probably need to see your code to truly answer that, after your Tx ID you should have a code line like

unsigned char stmp[x] = {0xA0, 0xB2, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

if that does not work you should reverse sequence as its a transmission sequence so it would look like

unsigned char stmp[x] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xB2, 0xA0};

but it would be easier to see your code to see what you are transmitting


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## rx7r3ev (Dec 11, 2018)

I've attempted to reverse the CAN message but to no avail. Here's my code:











Also here's my part number of the APM:











This gives a context on how my bench setup is laid out:











When the high voltage input is not provided (or plug into the APM), the power supply that provides +12Vdc to the APM consumes current. I've notice that when I plug in the HV input, the APM is not consuming power anymore from the power supply. I can disconnect the power supply and the APM would still work and still be sending CAN messages.


Here's the input voltage:












Something to take note is that when the HV input is plugged into the APM, the current of the power supply to the APM goes to ZERO.












And finally, here's what the serial monitor is reading back from the APM. As observed there are two IDs that are coming back 1D6 and 495.












Anything I'm missing why its not providing the output voltage? Thanks!


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## x.l.r.8 (Oct 20, 2018)

I have to write the code out before I can work it out, I’m not that proficient at looking at the screen and analyzing. I’ll try and see what I can tonight. In the mean time, I’m sure you have this document but if not check your wiring. 

https://d28lcup14p4e72.cloudfront.net/130863/2161036/Chevy_Volt_DC-DC_documentation_12_29_2014.docx

I usually say take it apart totally and rewire cable by cable because it’s hard to undo the brain if it’s convinced it correct already.


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## rx7r3ev (Dec 11, 2018)

x.l.r.8 said:


> I have to write the code out before I can work it out, I’m not that proficient at looking at the screen and analyzing. I’ll try and see what I can tonight. In the mean time, I’m sure you have this document but if not check your wiring.
> 
> https://d28lcup14p4e72.cloudfront.net/130863/2161036/Chevy_Volt_DC-DC_documentation_12_29_2014.docx
> 
> I usually say take it apart totally and rewire cable by cable because it’s hard to undo the brain if it’s convinced it correct already.



I finally got it to work! The setup needed to have a load for the APM to kick in. I've used an old water injection motor to load the system and APM starting upping up the voltage.


Thanks for all the help. Below is my code in case it will useful for anyone.



> #include <Arduino.h>
> #include <SPI.h>
> #include <mcp_can.h>
> 
> ...


And here is a screen shot of the logger and volt meter showing the proper voltage:


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## rx7r3ev (Dec 11, 2018)

I finally got it to work! The setup needed to have a load for the APM to kick in. I've used an old water injection motor to load the system and APM started upping the voltage.


Thanks for all the help. Below is my code in case it will be useful for anyone.



> #include <Arduino.h>
> #include <SPI.h>
> #include <mcp_can.h>
> 
> ...


And here is a screen shot of the logger and volt meter showing the proper voltage:


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## x.l.r.8 (Oct 20, 2018)

Thanks for sharing, it’s a definite solution for the DIY. I cheated and use savvyCAN to do the hard work. I’m sure programmers can reduce the code but if it works don’t fix it. The joy with this project if the Transmitter stops once it’s turned the Inverter is on it keeps working at 13.5v which makes it a great system when using less than reliable components like arduino UNO’s.


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