openinverter forum

Hi All,

So I have a 2014 Chevy Volt Battery, and I finally got around to disassembling the case. I measured the voltage and it's at 340.5 V. I'd like to connect this to my 450h transmission to give it a full power test, but I have questions.

My questions are:
1) what's the nominal voltage range?
2) At this voltage, should I go ahead and give the 450h a test power on?
3) should I stop where I am now and invest in charging solutions?
4) I suspect that a Volt charger will be the way to go, can anyone point me in the direction of resources that show how to use the Volt charger?

Thanks!

1) It's a 96 series battery pack, meaning if you consider a cell voltage range of let's say 4.1V full, 3.1V empty, that'll be 394V full, 298V empty.

2) It's less than half full but if it's at least somewhat balanced (probably is), there's quite some kilowatt hours left in it before empty

3) Obviously you'll need to charge it at some point so having a plan and looking for good deals makes sense. Also, you should figure out a BMS for it too.

The Volt battery is 390V when "full", which is 87% SOC according to the NHTSA fire report (see p.100) http://www.nhtsa.gov/staticfiles/nvs/pd ... eports.pdf

I think GM don't go any lower than 330V in normal use (i.e. for 10kWh of usable capacity)

celeron55 wrote: ↑Mon Jan 18, 2021 9:46 pm 1) It's a 96 series battery pack, meaning if you consider a cell voltage range of let's say 4.1V full, 3.1V empty, that'll be 394V full, 298V empty.

2) It's less than half full but if it's at least somewhat balanced (probably is), there's quite some kilowatt hours left in it before empty

3) Obviously you'll need to charge it at some point so having a plan and looking for good deals makes sense. Also, you should figure out a BMS for it too.

Thanks! Ok, great. I'll go ahead and do a short test run with the battery as it is. I mostly just want to confirm that everything works at full power (with my high voltage junction box and pre charge, of course).

3) Can I use the BMS attached to the Volt batteries? Using what's there already would be ideal for my pocket . If not, what BMS do you recommend, keeping a modest budget in mind.

clanger9 wrote: ↑Mon Jan 18, 2021 10:11 pm The Volt battery is 390V when "full", which is 87% SOC according to the NHTSA fire report (see p.100) http://www.nhtsa.gov/staticfiles/nvs/pd ... eports.pdf

I think GM don't go any lower than 330V in normal use (i.e. for 10kWh of usable capacity)

Thanks for the report!!! I'll gladly take a look. I think I'll give my system a short power up to test things.

Assuming you have all of the BMS modules, you can use SimpBMS as a controller if this is the Gen 1 volt battery. (I think so).

If not, I'd probably use the ZEVA gen 3 stuff, as a distributed system is the way to go, I think (keep the HV near the battery, at the monitoring / balancing boards, and not going all around the car...).

-Matt

mdrobnak wrote: ↑Tue Jan 19, 2021 3:31 am Assuming you have all of the BMS modules, you can use SimpBMS as a controller if this is the Gen 1 volt battery. (I think so).

If not, I'd probably use the ZEVA gen 3 stuff, as a distributed system is the way to go, I think (keep the HV near the battery, at the monitoring / balancing boards, and not going all around the car...).

-Matt

Yeah Gen 1, I believe I have all the BMS modules (the black boxes on top of the batteries, right?). Great! Is there a "how to" to connect them to the OEM batteries?

There's basic wiring info in the SimpBMS manual.
https://github.com/Tom-evnut/SimpBMS

and the code itself is here:
https://github.com/Tom-evnut/AmperaBatt ... /VoltBMSV2

It can be run on a Teensy 3.2, but Tom has a nice PCB which provides contactor control, 12V power, etc..

-Matt

That's great!

I'll take a look at the manual for sure.

Where can I purchase the PCB?

bobbyj_408 wrote: ↑Tue Jan 19, 2021 5:54 am That's great!

I'll take a look at the manual for sure.

Where can I purchase the PCB?

viewtopic.php?t=131


Please please take the time the read threw the forum and wiki!

I found a bit more data on the Volt battery. This test suggests max pack voltage is 398.4V, min is 288V for the full 16.6kW capacity:
https://www.energy.gov/sites/prod/files ... t_3929.pdf

mdrobnak wrote: ↑Tue Jan 19, 2021 5:20 am There's basic wiring info in the SimpBMS manual.
https://github.com/Tom-evnut/SimpBMS

and the code itself is here:
https://github.com/Tom-evnut/AmperaBatt ... /VoltBMSV2

It can be run on a Teensy 3.2, but Tom has a nice PCB which provides contactor control, 12V power, etc..

-Matt

Hmmm, so I took a look at some of the documentation. Is there a schematic layout diagram of Tom's PCB? I ask because I am not sure if I need it or not. What would I gain from it? I currently have a Zeva precharger to control the positive contactor, this should be enough correct?

If I dont use the PCB, then all I need to do is use a Teensy, and make four connections, right? Connections would be: 5V, GND, CAN_H, CAN_L. Am I thinking of this correctly?

Also, noob question, but where do I connect the charger to the battery (assuming I would use a Volt charger)? Does it connect pre main contactor, post contactor..... I assume SimpBMS would control it, but how?

As far as I know, that's where Tom's making his money, and the schematic is not available. It's a little pricey for what you're buying, but you're also buying some support as well - I found a bug and he was very quick to fix it...but then I fixed the next bug myself. So...If you can design the support hardware to make it run off 12V, more power to you. If you want something done for you, buy his board. It also supports working with Solar systems like the Victron Energy, etc...

If you do go down the route of doing it yourself, use one of the Teensy 4.x boards - you need two CAN ports, and he's got a serial to CAN adapter for the Volt (as it's 125 kbit/sec) so you can do 500 kbit/sec or whatever you need for the main bus. But then you'll have to massage the code a bit as well.

Tradeoffs!

-Matt

Thanks Matt!

Sorry, I assumed since the code is open, the HW was open. Tom should totally be compensated for the good work he's doing, makes sense.

Hmmm, I think I might give it a shot with the Teensy 4.x. Is there an example out there with a Teensy 4.x and appropriate connections for the Volt pack? Looks like one CAN bus will be for communicating to the master BECM and the other... for the slaves??

You don't need the BECM - the SimpBMS takes place of that. However, you'd probably want to connect to the rest of your car somehow... yes

mdrobnak wrote: ↑Wed Jan 20, 2021 6:34 pm You don't need the BECM - the SimpBMS takes place of that. However, you'd probably want to connect to the rest of your car somehow... yes

Of course! Yeah, that makes too much sense. Glad I asked!

So, what are the contactor layouts for charging? I'm starting to suspect that the charging lines would have their own contactors?

Hello everyone.
I want to know phisical measures of chevrolet volt gen2 battery cells. I know thinkness of gen1 is 6.3mm, widgh 127, length 177mm.
I want to know sizes of gen2 cells.
Can anyone jmhelp me?