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Planning EV Race Car

13363 Views 30 Replies 11 Participants Last post by  dougingraham
Hi All,
My name is Alex. I'm a big EV enthusiast and I have decided that I want to build a race car. I have little experience disassembling and reassembling cars but I am fairly apt with my hands and I'm fairly bright.
Here's a little bit about me, I am a student at a small university in upstate NY. I worked for two years for the University of Toronto on the original Surface and Google Glass with regards to notifications. I am going to major in Physics.

I have considered which car will serve as the basis for my car. I would prefer if I kept that private for now. Its a small car, perfect for racing.

The range I would like to achieve is around 80 miles at very high speed.

Yasa 750 (H if available) x4 probably.

Battery pack ideas? Looking for Li-Ion

Rimac Battery Packs - if they are for sale.
Drive inverter?
Reinhart Controllers - PM250

Basic knowledge of EVs:

Energy goes in to the car from the grid through an adapter into a charger. The charger fills the pack. When you push down on the accelerator the controller allows current to flow into the inverter which converts the DC -> AC to spin a brushless motor. The motor usually connected to a reduction gear or gearbox spins the gears etc.

Is that correct? How does one program regenerative breaking?

That is really all that I have thought about.
I'm willing to push the limits financially right now. I would, however, like to keep track of the price of the parts.

Any and all help is greatly appreciated.

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150 miles at very high speed ... Battery pack alone would be near 30,000$ for a civic size car ...
The car is a single seater. Looks akin to an F3 car. Space is going to be an issue, as is weight distribution. I know that the battery will be costly. I'm interested in seeing how costly. Do you know of any suppliers with battery packs that have a very high output?

Rinehart controllers for the Yasa motors, one per motor.
I would need the PM-250 correct? As each Yasa 750 has a peak power of 200kW right?

Thank you,
Check out since space will be limited they can make batteries in any shape you want .... Very good power outputs but expensive obviously
Thank you for your help. From what I'm seeing, these batteries can only be charged at low voltage. I need to be able to charge them faster. This would work as a 12v for the electronics but not as the battery pack.

I am in the process of drafting an email to Rimac Autombili, what questions should I be asking about their battery packs?

So far:
Dimensions, price, weight, customization.

I know I need to know max output and continuous output. Can someone explain what that means?

Sorry if these are dumb questions, clearly I'm new to this.
No not even close - triple it $90,000

150 miles is difficult and expensive - add "at very high speed" and you are getting close to impossible

Tesla's get 200 miles + at normal road speeds, at 120mph + that will drop to about 60 miles
The 85kWh pack gets 260 at 320Wh/mi. That pack costs 30k (if I remember correctly) using 600Wh/mi I'd get 130 mi. Car has a low CD and I am hoping to keep it very light.

The issue is I wouldn't be able to fit an 85kWh pack in the car. If I'm lucky I can maybe fit a 65kWh pack. The car has maybe 140 in of usable length. Most of the space is in the back where the engine was.

It would be interesting to see if you can line the driver cell with batteries.

I draw the line at 90k for batteries.
You may not make it then. When researching the same thing for the Inhaler, I priced just the cells for a high-power Kokam-based pack at around $50K (much less range, but possibly more power than you're after?). That's not including connections, case - and most importantly BMS - you're not going to run these cells without a really good BMS, unless you just like the thought of roasting money over an open flame.
Okay. So what about swapping multiple packs around. Let's say that the price isn't a big deal. If I had multiple (5?) smaller pack with enough range for 80 miles, would I increase cell life? The way I think about it is that if I deplete one pack to 10% and I put it to charge (outside of the car) while the next pack is swapped in I would only be depleting at a faster rate.

What matters more, getting to 0 SOC or running through the SOC quickly?

Is BMS always separate from the battery module?
Hi, I am back with a couple of questions.

This article makes it seem as if an AC motor can only have a single speed transmission. Is it not possible to use multiple gears with an AC motor? If so why?

Do I have to do anything differently because I want to use an axial flux motor?

I'd like to create a parts list.

So far I have:
Drive Inverter

What am I missing?

Thank you all for your help. I really appreciate it.

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I've driven two cars with AC motors that utilize the vehicles transmission and clutch. There is no reason to not leverage the benefits of the transmission. The transmission does not know what's connected. AC, DC, ICE, or Hamsters
Thank you.


Seriously, if you are going to do this and make a "Real" race car, you should get a good (EV ?) race engineer on board before you waste a lot of time and money.
I'm here to learn. I'm young. I have no experience with EVs. I was asking for parts. I know that I need to learn more. I don't expect to just build this thing.

I just quoted a large pack made from our team supplier's lowest cost "energy" Pouch cells rated at 30C continuous.

30C Line Up
10kWH would be $9,000 (450BHP) 3 boxes
20kWh would be $18,000 (900BHP) 6 boxes
30kWh would be $27,000 (1350BHP) 9 boxes
or about $900/kWH and $20/BHP

Just for comparison a drag racing pack of my 6S 4.5Ahr 100C cells
$150 each 6PX15modules = $13,500
Boxes $2,250
Total $16,000
250VX100*6*4.5=675kW or 905BHP
or about $1800/kWH but only $17/BHP
but, these obviously weigh half as much and are half the volume.

Fill in your pack requirements, multiply it out and see if that's in your budget.....
So if I'm understanding this right, faster discharging packs are cheaper per kW/BHP but more expensive per kWh.

The benefit to pouch cells is that they are malleable (to an extent) so I could shape them around the space that I have remaining in the car, correct? What are the downsides?

And people on this forum tend to prefer Li-po because of the slight increase in energy density over Li-ion right?

How does one determine their discharging requirements?

What is the rated voltage on those packs? The 30c ones.

Thank you,

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Sorry, I've been kind of MIA the passed couple of months. I was wondering if anyone has any experience using both supercaps and li-ion batteries in the same pack? How would that work? Sorry if this is a stupid question, I am just trying to acquire some general information.

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