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Tesla Powered Cobra Race Car

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I'd like to present our Tesla powered Race Car project. The car utilizes a custom designed chassis, drivetrain from a Tesla P85, body from a classic 427 Cobra, and a battery pack from a Kia Soul EV.

I am a long time road racer (Sunbeam Tiger, Mustang GT1, Toyota MR2) in the PNW and have been wanting to build an electric race car for a while. However, up until now, the cost of doing this has been prohibitive. The availability of OEM EV components in the salvage yard has changed things.

This car is being collectively built by a group of friends who love the idea of doing something different. We have been working on the project for since December 2015, and are hoping to have the vehicle on track for testing this summer. We call ourselves "EPower Racing"

The motor is from a Model S P85 which is rated at 310 kW peak. However, we have no illusions that we will be able to run the motor at anything close to that for sustained periods due to overheating of the motor/inverter. We are putting in lots of extra cooling but only testing will tell if that helps. All reports we hear of from Tesla Track Days show Model S's going into power limiting within a couple of laps. For longer events, we will probably limit the maximu power to the motor to prevent heat build-up. Although we will have regen capabilities, we will most likely not use it the same reason. (Regen would also upset the brake balance as well which would be undesirable for a race car).

We realized very early on that the massive available torque and an open differential without the benefit of Tesla's traction control system was not a good combination. We worked closely with Jack Rickard/EVTV and Quaife Engineering to produce a custom torque biasing differential. These are now available from EVTV.

We chose the Kia Soul EV as the battery pack donor largely based on DOE test reports which showed it as one of the few OEM packs capable of putting out over 300kW for sustained length of time. It is also one of the lightest packs available. The 30 kw-hr pack (27 usable) only weighs 400 pounds. We purchase what was probably the first Kia Soul EV that was written off, and hauled it across North America! It was fully functional vehicle which allowed us to do some reverse engineering of the CAN bus. We are able to utilize the factory charger for both regular and ChaDeMo charging and obtain cell temperature and voltage data from the BMS. We will be limited in the duration of our runs due to the pack size, but we didn't want to double up on the pack before we even had any real world test data.

The chassis was designed in Solidworks including FEA optimization. The chassis with roll cage weigh about 220 pounds. VR3 engineering took our CAD files and CNC cut and bent all the tubes.

The suspension utilizes C5 Corvette spindles and hubs to keep costs down. However, since we were designing both the frame and A-arms, we were able to dial in exactly the geometry we needed using our SusProg3D suspension analysis program.

Total design weight of the vehicle with driver is 1800 pounds which, even with a torque limited motor, should give us a very good power to weight ratio.

The goal is to have the vehicle on the dyno early spring, then on track for testing in the summer.



https://www.youtube.com/watch?v=Ci8kHAb6iVw
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Looks like fun! FWIW, You might be interested in "Dashware", it's a software package that can integrate video/GPS info to give added entertainment value to your videos.

Glad the car worked okay for you, hillclimbing will definitely find any weak points in a vehicle.
 

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Thanks for sharing that. :)

The lack of noise is bizarre for a competition video - wind noise nearly completely covers both motor/gear whine and tire sounds. I was expecting to hear both the drive unit (varying with road speed) and the tires (at highest lateral load).

It looks like there were a couple of "interesting" moments there with loss of rear traction on corner exits.
 

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hi tiger, i'm interresting in using a kia battery pack in my next project.
i have the battery pack but without the car, so i can't work on a full fonctionnal can bus.
do you have any information on the can string from the bms ?
i may be interrested in used the original kia charger too.
 

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Discussion Starter · #45 ·
Depending on what you want to do, you can just use Torque Pro. You can monitor all variables including individual cell voltages, pack temperatures, current, SOC etc. If you need to actually work with the data, you need to be able to generate multi-frame OBDII messages. We did that in our datalogger. It involves sending a CAN query string, waiting for a response, sending an ACK, then receiving and parsing 62 bytes of data. I can supply some sample code if you want.

If you want to utilize the onboard charger, we have some recorded CAN traffic that you can replay in an endless loop that will fool the charger into starting up. I can also send that to you if you want.
 

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I'm interested in the pack. More Soul EVs on the road, more finding their way to the scrapyard.

I might have a lead on one locally but don't know the pack. I've worked with Volt packs in the past and some oddball BAE modules so I'm getting the hang of this stuff gradually.

The Soul pack seems to be stacks of NMC pouch cells. Apparently air cooled which is a plus for me, simplicity-wise. Does it break down well? Can you break it down into individual bricks and reorganize as you wish or are there just small stacks and tall stacks and that's it?

And what's it worth used do you reckon?

If someone knows of a good link to Soul pack info elsewhere let me know. I'll keep hunting.

Oh, and your project is SPECTACULAR!:eek:

~ reid
 

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The modules inside are pretty interesting.
Each BMS tap is fused for 2A with a standard car fuse.
The pack does come apart and the cells can be removed, but 2 cells are welded together in parallel.
Here are the two types of modules in the car with the pictures of how they break down.

It also looks like you can take 2 modules and construct them into one larger module of however many cells you need, but in order to do that, you need to remove the BMS voltage tap assembly. They are spot welded together.

14s pack
https://www.ebay.com/itm/Kia-Soul-4...AOSw1ExcEpOo:sc:FedExHomeDelivery!66062!US!-1
10s pack
https://www.ebay.com/itm/223282094685
 

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If someone knows of a good link to Soul pack info elsewhere let me know.
This is the most useful that I have seen... that doesn't mean much, but it might help:
Comparing layout of the Soul EV battery with other EVs

Apparently pouch cells with polymer electrolyte and NMC cathode, forced air cooled.

While this car has moved on to a custom pack using Chevrolet Bolt cells, the original Soul battery pack seems to have been used complete and essentially intact, "folded" down the centre line so sides of the modules which were originally facing up now face left and right. Right?
 

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Depending on what you want to do, you can just use Torque Pro. You can monitor all variables including individual cell voltages, pack temperatures, current, SOC etc. If you need to actually work with the data, you need to be able to generate multi-frame OBDII messages. We did that in our datalogger. It involves sending a CAN query string, waiting for a response, sending an ACK, then receiving and parsing 62 bytes of data. I can supply some sample code if you want.

If you want to utilize the onboard charger, we have some recorded CAN traffic that you can replay in an endless loop that will fool the charger into starting up. I can also send that to you if you want.
Wow, this is a really neat build! I'm looking at using one of these Kia Soul packs to use in my 2000 Ford Ranger EV. So far, your project is the only one I've been able to find that has used a Soul EV pack...
I actually caught your email at the end of the video on your Youtube channel and sent an email to you.
Is there any way you could send me the sample code for using the BMS and onboard charger? What modifications did you need to do in order to re-use the original BMS from the Kia?
I'm basically trying to look for all the info I can possibly get on using these packs, haha.
 

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Hi all!!! Im looking for a kia soul battery on scrape yard ... Im trying to build the conversion with less money possible... Im reading that someone crack the code to re use the charger and the bms of the soul..


Who can i contat ct to trying to get this code??? It will definetely help with saving money on bms and charging!!!!!

But i dont know who i can reach to help!!!
 

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I thought everybody might be interested in an update.
Yes! Thanks. :)

For anyone who has suggested using Model 3 battery modules, I encourage them to look at the size of this pack, rearranged as one stack of all four modules extending from the front axle line (ahead of where the front the engine would be in this car)
122125

...to what would be the passenger seatback if there were room left for a passenger:
122126

Of course in this stacked arrangement they are higher than they would be in a stock Model 3, despite being in a race car... but getting them in the car at all is impressive. :)

It's interesting that the Model S motor has no more continuous power capability (due to the cooling limitations) than the motors from ordinary economy EVs.

I hope that people now realize that the Model 3 is not a switched reluctance motor. It is, like most EV motors introduced over the past decade, a synchronous (not switched) reluctance and internal permanent magnet (IPM) design. Elon Musk called it a switched reluctance motor early on (presumably seeing "SR" in some briefing notes and not understanding the difference), and the myth has stuck.

I always thought that this car really should have the motor ahead of the axle line, as explained in the video, but I certainly understanding starting with the Model S drive unit, based on availability of the drive unit and aftermarket support. It's good to hear that the cooling is much better than in the Model S unit, probably to a substantial extent to the lower heating in the IPM/reluctance rotor compared to an induction rotor.
 

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wow great, I didn't realize there were any 3rd party solutions to control the Model 3 motor yet. The website isn't clear but it sounds like if you want control over regen and maximum motor power you need to use a model 3 battery pack as well. Is that true?
 

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The website isn't clear but it sounds like if you want control over regen and maximum motor power you need to use a model 3 battery pack as well. Is that true?
I'm only taking a somewhat informed guess from reading their website, but if you are referring to the "Boost 50" product, this is for an intact Model 3 rather than DIY use of Model 3 components - it would work by intercepting messages between components and replacing them with faked messages that omit the information that stock system uses to limit power to protect the battery. The base controller for DIY use probably allows the same higher power level and unrestricted regen, not caring if you fry the battery. But you should check with Ingenext for the real answer.
 
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