Attempting to hack a Chevy Volt Drivetrain

kerrymann · Jul 10, 2014

Chevy Volt drivetrain

I actually bought the entire EV drivetrain from a 2013 Chevy volt with 7k miles. After 3 attempts of buying a new volt battery (paying for, waiting months, and then getting a refund from the dealer) I just went with a scrapyard unit. A few weeks ago I started tearing apart the Chevy volt pack and video taped the tear down and here are the links:

https://www.youtube.com/watch?v=00tTckGUv7I&list=UU1haWsGv-HcI10lapf4MBgg
https://www.youtube.com/watch?v=00tTckGUv7I&list=UU1haWsGv-HcI10lapf4MBgg

It's my first time shooting and editing video so future videos should be better quality

Here is a picture of the drivetrain sitting next to our daily driver volt (30,000 EV miles and going strong):

When I bought all the parts I made sure to get all the important wiring bits.

For those that don't know, the motor and inverter are very interesting, the motor is actually 2 motors. One is nested inside the other in a coaxial configuration and the inverter is actually two in one as well. It will take quite a bit of work to figure out how to talk to the inverter and very likely outside my capabilities (I am a ME not a EE for a reason

. But a 111kW AC drive system for well under $1000 is a big opportunity for the DIY community.

Here is the engine side of the gear box. And on the bottom you can also see where the passenger side axle shaft comes out:

The Volt pack has a disconnect mounted on top. It is not the easiest to pull but I am pretty sure it is fused.

The pack cover is easily removed and the the whole pack is easy and straight forward to work on.

The pack is configured in 3 modules that are made up of 48V and 24V modules. The pack measured 370VDC total and is likely near a "full" charge. Keep in mind that chevy's version of a full charge is actually 80% SOC.

I took video of the whole process and will post it up on youtube once I get it all edited. The modules are pretty easy to breakdown and I will upload the pics from that process next week.

skooler · Jul 10, 2014

Awesome!

Keep us updated

piotrsko · Jul 10, 2014

Yup it's fused, 350 amps. Mine will deliver that for at least 2 minutes so far. Full Charge is rumored to be 400 volts. Lower limit 240 volts

The big thing would be to hack the battery for bms and other controls.

Chevy seems paranoid, everything inerts the pack.

Where did you get yours?

samwichse · Jul 10, 2014

Is the inverter water cooled?

kerrymann · Jul 10, 2014

I got it from a junkyard. It took me a bit because I didn't find one locally and it took a few attempts to find a yard willing to ship everything. Once I got a deal worked out on the battery the other parts were cheap. Even if I just end up scrapping the motor I won't be out much money. Because right now there is 0 market for them. If you wreck a volt enough to damage these parts it is going to be scrapped and with 8 year and 100k mile warranty there is no real replacement market.

As far as the BMS, I know there are some on the forum looking at making the OEM BMS work which would be very cool but in the mean time I want to wire it to my Orion. With the right harness it should be a simple plug and play from the Orion to the individual modules. I have been talking to a few people about buying a harness (including Andrew at Orion) but nobody makes this so I am designing up my own.

piotrsko · Jul 10, 2014

I'm guessing you have yours apart so you've seen the Orange bms tie points. Just whack the control board side off and add your own connection scheme. Just unplug them from battery first as I believe they are live. Should even be a standard spec connector.

kerrymann · Jul 11, 2014

piotrsko said:
I'm guessing you have yours apart so you've seen the Orange bms tie points. Just whack the control board side off and add your own connection scheme. Just unplug them from battery first as I believe they are live. Should even be a standard spec connector.

Yep. That certainly is an option. Ideally a cable could be made available that would allow anyone to plug straight from the modules to the Orion without even picking up a wire crimper.

I have been searching for a connector but in the mean time I could just depin the original connector a repin it.

Here are pictures of the 6 and 12 modules.

Also I forgot to mention that there is a current sensor located in between the front and middle modules

piotrsko · Jul 11, 2014

Sensor is lem product dhab s44 a 0 to 600 amp inductive coupled DC. Runs on 5 v ref. Darn kindle won't paste the pdf here.

I'm lusting after modifications to the mains relays after I figure out what they break. 350 amp one shot perhaps.

Also many assorted imbedded thermocouple, and looks like a 600 watt heater element

kerrymann · Jul 11, 2014

Thanks. If you can upload the .pdf that would be great! I have not noticed the heater yet. Where is it located?

Each module has a TC. Not sure what type though? (maybe a thermistor for all I know yet)

esoneson · Jul 11, 2014

kerrymann,

I'd like to use the Volt pack, but I'd like to break it up so get 190V and twice the Ah.
Question: Do you think the inter-module cabling can handle more than 300 Amps?

Looks like inter-module connections include HV cabling, cooling fluid and BMS cabling. Am I right or is there more to it?

Thanks. You are doing an excellent job at documenting this effort. Can't wait to see the vid.

Eric

kerrymann · Jul 11, 2014

You could actually do that pretty easily. There are 7 of the 48v modules and 2 24V modules. They can be reconfigured into 2 192V packs (or 4 packs depending how it will be cooled) in parallel. The design of the modules will not handle high currents but putting in parallel will double the current and get you the voltage you need.

piotrsko · Jul 11, 2014

http://www.lem.com/docs/products/dhab%20s44.pdf

heater is in input coolant manifold, orange 2 wire plug about 1/8 dia pins

each module has temp sensor.

two in metal endplate coolant manifolds, one in fuse (at least there is an impedance) two in wire charge plugs, thought they were T/C might be thermistors.

kerrymann · Jul 28, 2014

Thanks!

CKidder said:
The way the Prius (at least the older 2004 version jddcircuit has) works is dead stupid. I cannot imagine how anyone could make a setup like that and sleep at night. The Toyota engineers should be ashamed. I also cannot imagine that a nearly new Volt would work like that at all. CANBus control of vehicle hardware is very common these days and would be a fairly reasonable guess. Canbus works over two wires and at very low voltage (around 0 to 1.4V differential between the wires). Unfortunately, without a schematic it could be interesting to find those two wires if they even exist. They would likely be twisted together and needn't be very large.

If it is canbus controlled (and I'd be 90% sure it is) then I just might know somebody who likes to hack on canbus controlled hardware. The hardware and software exist but tend to be expensive. There are, however, people who are working to change that.

What I'm really trying to say is: I helped build a replacement ECU for electric cars and I've also been turning that same ECU into a reverse engineering tool to crack new hardware. After the comm scheme is reverse engineered the same ECU used for the reverse engineering is then re-flashed to actually drive the hardware. This should save time and money and lead to less wasted hardware.

Sounds good to me. What to work on one for a volt? I am still trying to get a hold of a wiring diagram and hopefully it is all canbus but we will see. I have been busy in the barn dealing with permit issues upgrading my barn with 100amp service but that is another story.

Looks like Jack posted parts of my videos on EVTV but there wasn't much lead in. I was hoping that would help get people interested in cracking the wiring of the inverter but I think he has more projects then can handle as it is.

jddcircuit · Jul 12, 2014

Good luck kerrymann.

I got outbid on a couple online auctions but not giving up. I need the battery for my conversion using a Prius motor and inverter but I plan to hack the Volt drive train as well if things go as planned.

Jeff

kerrymann · Jul 19, 2014

I finally got the video's edited and posted to youtube.

https://www.youtube.com/watch?v=00tTckGUv7I&list=UU1haWsGv-HcI10lapf4MBgg
https://www.youtube.com/watch?v=00tTckGUv7I&list=UU1haWsGv-HcI10lapf4MBgg

It's my first time shooting and editing video so future videos should be better quality but I hope you guys find these informative.

kerrymann · Jul 19, 2014

And here is a great video that i just found where GM shows how the volt system works:

https://www.youtube.com/watch?v=AX5ZwzNwTc4

Much better job then I would have done with some shaky camera video pointing at things under the hood.

Moltenmetal · Jul 19, 2014

Wow, you're made of stouter stuff than I am- that drivetrain is frighteningly complex based on the video...

kerrymann · Jul 20, 2014

Not really. Take the engine out of the mix and you only have 2 modes and there is nothing that says that you can not just operate in one mode.

I started this for the battery and the price for the rest was too good to pass up. Trying to get the inverter and motor is a long shot but rewards are not without risk.

aeroscott · Jul 20, 2014

Great stuff, This is state of the art.

jddcircuit · Jul 21, 2014

kerrymann,

Are you sure that the Volt inverter interface is CAN bus only? The Prius inverter/motor that I am using does not use CAN bus and hacking it is very different than just CAN decoding.

Have you come across a wiring diagram of the Volt? This might give some insight into the interconnections and type of hacking required.

Thanks
Jeff

kerrymann · Jul 21, 2014

No I am not sure at all. That is in fact my biggest concern. I have not found any wiring diagrams yet but right now I am focused on the battery. I am worried that the only way to get it work is if it can communicate with all of the other controllers on board. You see this a lot in engine swaps and it is can be a mess unless you can reflash the ECU.

kerrymann · Jul 29, 2014

According to people on the volt forum, these guys are supposed to have wiring diagrams for the volt but I have been trying to sign up for a account for the past week with no luck:

http://www.autocats.ws

dotrick · Oct 17, 2014

Hello,

I bought a Chevy Volt Battery too... I'm looking for some informations about the CAN Bus and BMS.
Do you have an electrical schema to switch on the BMS and read messages on CAN BUS?

Thank you

crashedup · Oct 20, 2014

Hello! this is a message to the moderators!
There should be a new title in the forum for hacking oem ev's, where everyone who has tried or has info on oem ev parts, because that is our future as DIY. It is the cheapest route out there and we end up with high qulity parts from junk yards for peanuts!
Example; I called around and a battery pack out of a volt or leaf goes for around $2000, and that's without negociation because they have no idea what to do with the stuff! Imagin if we could use everything from a leaf or volt, motor, charger, battery. We could make a sub $10,000 quality ev!

kerrymann · Jan 31, 2015

Hey all,
Sorry for the lack of updates. I realized I haven't posted anything here but I did crack a lot more into the volt pack and started putting up more videos of what I found along with progress on the e30:

https://www.youtube.com/user/d55guy/videos

I will be putting up more this weekend.

I am working with Jack's group on reverse engineering the components taking captures from my 2013. They gave me a candue and it is a bit of a learning curve on the CAN but things are progressing. It really helps having my volt that I can use to sniff the canbus while doing specific operations.

I have spent most of my time on the battery side. I have stripped down a few packs and developed my own mounting system. I was so anxious to test it all I pulled the enerdel that I just put in my e30 and put in most of a volt pack and wired it all up to my Soliton1. If I can get a throttle figured out this weekend I hope to take it for a test spin.

eldis · Jan 31, 2015

kerrymann said:
Hey all,
Sorry for the lack of updates. I realized I haven't posted anything here but I did crack a lot more into the volt pack and started putting up more videos of what I found along with progress on the e30:

https://www.youtube.com/user/d55guy/videos

I will be putting up more this weekend.

Thanks for the work you're putting in the videos!
I'm just going through the videos related to the battery - you got some things a bit wrong, so I would like to clarify it (didn't finish watching it all yet).

Battery interface module:
- The big ceramic white resistors are not heaters, they are precharge resistors. They are used together with a precharge relay (one of the small relays) and a MOSFET PWM, to ramp up the voltage before the main contactor turns on (so you don't get any sparking).
- One of the water connectors contains a HV heater (working from a pack voltage), again, controlled by one MOSFET
- All precharge, heater and contactors can be controlled externally, not using BMS module (it does not interface to it at all). Using X1 and X2 external connectors

I did reverse engineer most of the Chevy Volt drivetrain, but I'm still analyzing bits here and there, so I didn't want to release an incomplete documentation. Write me a PM if you want to cooperate on it.

piotrsko · Feb 1, 2015

Heater is in the passenger side water cooling manifold. 2 pin Orange connector going to relay module ( I think, mine is scattered).

Relays are good for average 10 amps on the small, 350-400 amps on the big mains, 600ish break on a one shot over current event. Nice panasonic hydrogen suppressed contacts which disassemble using a torx

Flat oem wires good (so far) 250 amp. I got nervous and yanked them.

Current sensor between module 1 & 2 is a 2 part hall sensor good to 400 amps or 20 amps. Rubber center plug. Offset is 3.80, voltage declines to 0. I am running it on 5 vdc, goes to 12. Building an inverted opamp to drive my jdh 404.

ElementalEnergy · Feb 10, 2015

Hey folks. We are getting ready to purchase a Chevy Volt battery pack from a pretty new wrecked volt (was hit in the front). Since they just got the whole car in, we were wondering if there are any other bits and pieces that it might be worth pilfering from the car. Cooling pumps, contactors, heater etc??

Thought you all might have some insight after digging around in these parts for awhile. Any bits and pieces that might be nice to have around for our build? Thanks so much for putting in all that work!

Build thread here:
http://www.diyelectriccar.com/forums/showthread.php/planning-1985-vw-doka-conversion-140210.html

piotrsko · Feb 11, 2015

Depends on how you get the car. If it is your car with complete access, then everything you might think you need. If it is their car and you are buying parts that they yank, power steering pump, battery coolant pump, battery charger control module, A/C compressor pump, both ends of any harnesses for the modules you buy. All the contractors that are worthy are in the battery, everything else is CAN controlled. The wrecking yard is going to hacksaw or cutting torch stuff out, cut harnesses, and just generally booger up the removal unless you are there to supervise. Make sure you get the disconnect safety inert plug from the top of the battery, I hear chevy is prissy about selling replacements.

GET THE VIN # !!!!!! That helps the dealership sell you stuff.

BTW us old guys call that a combi

kerrymann · Feb 11, 2015

Besides the obvious stuff get the charger on the passenger side front bumper if It is not damaged (Often it is). It has been hacked and its a nice unit.

There is the DC DC converter in the trunk which can put out some serious power.
The J1772 inlet is a good quality one. Check the truck for a 110v charge cord. The volt has EPS so useless you can make the whole rack work the power steering won't be easily used. The heater is a good one too and I just picked one up to start hacking (100 bucks). I would pick up the coolant pump and heat exchanger for the battery system. Definitely get every wiring connector for every part you buy withth a min 6" pig tail.

skeyes · Dec 4, 2016

kerrymann said:
Besides the obvious stuff get the charger on the passenger side front bumper if It is not damaged (Often it is). It has been hacked and its a nice unit.

OK this is awesome. I was just thinking about what I should do for a charger... I am planning on using chevy volt battery packs for my rx8 conversion.

Where can I find the hack information on the chevy volt charger?? What hardware do I need to get it to work?

Thanks for any info you can give!!

I watched your vids on the volt battery BTW and I am convinced to go that route. The performance and the savings over LifePO4 is too good to pass up. 600KW should be enough lol

kerrymann · Apr 12, 2015

I got a round to putting up some more videos. People kept asking me about how and where to get them:

https://www.youtube.com/watch?v=RbcbhGPp2PQ

And also I got some good information about the power capability of these volt packs courtesy of the DOE:

https://www.youtube.com/watch?v=HYrhykqpyj4

Sorry in advances as they are kind of long an rambling but if I waited around to edit them they would never get posted (not unlike the other hours of video sitting on my hard drive)

I hope they are helpful,

YogaSlackerSam · Aug 25, 2015

hey Chevy volt Gurus,

Wondering if it is possible to put 5 volt battery packs together to get a 90kwh pack?

We are building a 4x4 overlander micro house and looking for 100 mile range for a 7000 pound aerodynamically challenged rig.

thanks in advance.

Sam

Attempting to hack a Chevy Volt Drivetrain

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