# New EV Supercar Project



## Anaerin (Feb 4, 2009)

Zen1 said:


> I'm currently working with a group of replica specialists who have been commisioned to produce an electric supercar. Me and a few colleagues are in China next week to visit some partners, and have an appointment with a well known cell manufacturer.


Sounds interesting, I'll certainly be following this with interest.


Zen1 said:


> The car will be constructed of carbon kevlar almost entirely and therefore be very light. Who here would use 1 motor (driving the rear wheels),and who would use four (1 for each wheel)? why??


Using 4 motors is problematic at the moment. If you have 1 per wheel, you either have to try and find suitable wheelmotors (Good luck), or you're using inboard traditional motors, for which mounting 1 per wheel will take a massive power drain (As there'd be no transmission), and include an immense amount of weight.

One of the best racing-type cars out there at the moment is "White Zombie", which used 2 motors connected together and driving the back wheels. That will give you 0-60 times of ~2.9 seconds.

I think the best option may be to have a "split 4wd" system, with 2 motors, one driving the front wheels, and one driving the back. This way, you get the advantages of limited slip between the two, you can balance (on the fly) the torque curves to provide power where needed, and you get the advantages of twice the torque. It also means you can use high-ratio differentials to let the motors run at their optimum range, without having too much loss coming from a synchromesh gearbox.


Zen1 said:


> How many cells (therefore power) will i need to create a 0-60mph in 3-4 seconds with a race-like range?


That's a VERY tough question, especially as you don't state what kind of race you're talking. Obviously a car to run a drag race will have vastly different power requirements to a LeMans car.

The first thing to consider when sizing your pack is what voltage you're going to use. If you're using AC, or if you're racing with DC, you want as high a voltage as you can get away with. Typically 300v+ for AC, and 144+ for high-speed DC.

Then you choose the type of cells you want to use (Probably LiFe4PO in this case), chain the cells together in serial to make a pack of the required voltage, and if necessary, parallel several packs together to get the capacity (and therefore runtime) required.


Zen1 said:


> i am rather dunce-like at physics calculations - someone please point me to a EV speed/distance Vs cells needed chart for dummies!


Physics and power calculations aren't that complicated, but there aren't generalised tables/charts for EVs, as there are too many variables to easily consider: motor speed, motor power, vehicle weight, differential ratio, tyre size, aerodynamics/drag, voltage, battery type (which gives voltage sag at certain draw rates), pack size, ultracapacitors (if used)... The list goes on. And of course, as you adjust one value (voltage, say), it affects all the others (the batteries do add to the weight, for instance).


Zen1 said:


> Also - can anyone recommend a good controller system/accelerator pedal for a supercar?


For DC, the answer used to be "Zilla", but they're not making any controllers anymore (AFAIK). You might want to talk to Qer and Tesseract, who are making their own high-power DC controller to sell.
For AC, there doesn't seem to be any "Universal" controller available. The only option is to buy an integrated system. Those don't come cheap, for one, and are typically only sold to large-scale OEMs.


Zen1 said:


> Who makes the best motors??


You'll hear many people arguing on this, too. IIRC, White Zombie uses a pair of Advance motors, but theirs have been custom rewound to handle the higher load.


Zen1 said:


> Batteries??? Thundersky???


Again, there's been a lot of discussion on this one, also.

For LiFe4PO, there seem to be 2 major contenders, Thundersky and Sky Energy. I've heard of a few vehicles being built with Thundersky cells, though none with Sky Energy cells (yet). It does seem, however, that Sky Energy also manufacturer cells for Thundersky.
For AGM, I believe the advice is to go for Golf Cart batteries, or Optima yellow-tops.
For PbA, IIRC Hawker is the name to go for.

This is all from my dim recollections, IANAL, YMMV, offer void where exempt, E&OE, contents may settle during transit.


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## engineer_Bill (Jun 24, 2008)

It sounds to me like you need to hire some engineers. What kind of commision? Volunteer? Some company? Individual with deep pockets? Give a little more information about what or why you are doing this. The type of car and the materials depend greatly on the desired application.


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## Twilly (Jan 22, 2008)

I second the 2 motor, split 4wd system. You could use both motors for accel, and cut back to one for cruising speed.


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## DIYguy (Sep 18, 2008)

I vote for separate wheel motors. This concept likely will eventually be the benchmark for performance licenced EV's.

EV's.http://www.worldcarfans.com/2060724.006/pml-builds-640hp-electric-mini


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## Alchemist (Apr 16, 2009)

How about the Eliica! I'm sure most of us have seen or heard about this car.

Here's the link to the documentary:

http://video.google.com/videoplay?docid=2539535432368595777


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## mattW (Sep 14, 2007)

I think the ideal situation would be a smallish on-board AC electric motor driving each wheel and a single 'smart' controller that not only controlled the acceleration but also adjusted the output based on the steering input. For example turning left while accelerating would put more power to the wheels on the right hand side, wheel speed sensors would allow power to be put on the wheels with the most traction while accelerating (i.e. if one wheel was on gravel and the other three on the pavement the ones with traction would get the torque). It would be like the world's smartest differential but without any of the losses associated with doing it mechanically. The four motors could just be off the shelf but you would probably have to commission the controller with an electrical engineer (or team of). The controller would be really really expensive. If that it out of budget then I agree with the two motor 4wd system with a front and rear diff.

Also, while thundersky are good for our medium power, high energy commuting uses a real sports car would probably want to use cyclindrical cells such as lifebatt or A123 because they can put out a lot more instantaneous power where thundersky don't really like being pushed too far. 3-4 seconds means you need the electric power to weight of the tesla or better (you will get better traction with 4wd). The tesla has 150W/kg or 6.7kg/kW.

I would spend the money on the powertrain before spending a fortune on carbon kevlar but perhaps I am underestimating your budget. Actually we probably need at least a general idea of your budget before we can really help with much...


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## Anaerin (Feb 4, 2009)

Alchemist said:


> How about the Eliica! I'm sure most of us have seen or heard about this car.
> 
> Here's the link to the documentary:
> 
> http://video.google.com/videoplay?docid=2539535432368595777


The documentary's from 2004! Where the heck is this vehicle now? Why have we heard anything more about this?


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## sunworksco (Sep 8, 2008)

Zen1 said:


> Hello All.
> 
> I'm currently working with a group of replica specialists who have been commisioned to produce an electric supercar. Me and a few colleagues are in China next week to visit some partners, and have an appointment with a well known cell manufacturer.
> 
> ...


The very best,proven and fastest drivetrain would be from www.acpropulsion.com in San Dimas,Ca.
You may want to base the cars dimensions on a proven race car from www.vintagespyders.com 
Make the suspension Porsche 996 5-link and custom control arms for the front suspension.
I have designed this for the 550 Spyder.
The problem with wheel motors is that the unsprung weight is to much and causes very poor handling and high wear on the uprights.
Better to use one front-wheel drive motor with Honda limited-slip differential with carbon fiber belt-drive.No transmission needed.
Front-wheel drive will provide better brake-regeneration system and balance the battery and drive-train arrangement.
I can provide you with cad software drawings for the suspension if you are interested.


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## Zen1 (May 2, 2009)

Hi Guys.

Thankyou for all your answers. I'm digesting it all, and here's a few answers/more points.

Hi Anaerin.

I'm glad it sounds interesting to you, its very exciting for us too.
Perhaps twin rear and front motors? 

White Zombie - Awesome, I just emailed the guy.

Having 3 modes (switchable through the controller)
1: Dragster mode
2: Le Mans Mode.
3: City Cruise Mode.

(Ok - so its a big ask hehe - but surely not too complex for the engineer we "obviously need to hire" <EngineerBill - tell me you can do this!)

To break speed records. To break Rally records. To produce a car for an average bloke?

Sky's the limit! (right Bill?)

Build all the cells into the monocoque for the perfect weighting?

I checked out zilla - they will be back online soon - thank you.

Very interesting that you say thundersky are major contenders. i'd heard that from someone thats been using them for a year. however, i posted this thread on endless sphere and thundersky were slated. was this a group buy gone wrong due to a bad batch? 

Hi Engineer Bill!

Yes we need the finest electrical engineer on the planet. any suggestions? please PM me if you do.

I shouldn't of said commission. wrong word. We (Whoever is involved in the project) will own it. but the deeppocketted people are standing by with financing, factories and logistics.

Whats and whys? well, who wouldnt want to create this if they had the chance? secondry to this is a EV city car project. if we can create a supercar then a city car would be a walk in the park.

Hi Twilly.

After everyones suggestions, i think we'll definately go with twin front and rear motors 

HI DIYguy

Seperate wheel motors -that was my first choice but everyones shooting it down! (maybe best to do it then!)

Hi Alchemist

Elliica - never seen it, heard of it. Awesome. Thanks for the link

Hi MattW

Seperate motors............. yup, i think it could be.

Who can make such a controller!

Seriously though - the price has got to be sensible. this will be a showpiece for other things but most importantly, the plans gotta be so watertight and the system so good, that its a winner for all involved in the project.

i can provide the shell, the cell filled monocoque and all mechanical engineering. i need an electrical engineer to spec the system/drivetrain/cells etc


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## Zen1 (May 2, 2009)

Hi Sunworks co.

Thanks for the links.

The designer is working on a design inspired by the Pagani Zonda R, The Ferrari P4/5 and the Mazda Furai

It will probably use un-equal A arm suspension set-up but will definately be based on current standard race car-super street car dimensions.

Thanks very much for the insight into seperate wheel motors regarding the weight - makes sense.

Also very interesting regarding your FWD system and Regenerative breaking stats, and suggestions for using Honda.

It would be great if you could provide some drawings/examples as you suggested.

Thanks.


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## sunworksco (Sep 8, 2008)

Zen1 said:


> Hi Sunworks co.
> 
> Thanks for the links.
> 
> ...


Drawings are expensive.


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## Zen1 (May 2, 2009)

sunworksco said:


> Drawings are expensive.


Thanks for showing your face my friend - good luck with your pot of gold.


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## sunworksco (Sep 8, 2008)

Zen1 said:


> Thanks for showing your face my friend - good luck with your pot of gold.


 Let me get this right.
You are building an EV supercar.
You want free engineering.
You berate members here when they give you free advice and web-links but do not engineer drawings for you "Pro Bono". 
Are you building a Tesla-like car or a "Shoe-String" budget car ?
My skills are capable of designing a Lotus Elise style aluminum monocoqe chassis with high-performance drive-train and suspension.
I am not finding a pot of gold,but just making a living.


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## Zen1 (May 2, 2009)

Ok mate. Lets stop this here.

I apologise for offending you.

I'm simply trying to make something special, and yes, we're on a shoesring budget. Doesn't mean we're stupid. If you helped us and it was a success then you would be part of that success. Maybe your very successfull already and therefore aren't too bothered, I can understand that.

I'm just looking for good advice from EV enthusiasts. I have had a vast amount of information from my post already, and am truly grateful for that.

I have a chance to build a dream, and I'm just trying to give it the best shot i can with the resources i have available to me.


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## sunworksco (Sep 8, 2008)

I have brilliant resouces at my disposal to create the best suspension and drive-train and can help you with the chassis but need to get more than just a sponsorship name on it.We could build two chassis components at the same time and my fee would be the duplicate part.I would be willing to work for just the chassis,suspension,wheels and tires.
You may want to build a reverse trike car with FWD.
I have a very good design for this only weighing 600lbs. with 17" center-lock pin-drive carbon fiber wheels weighing only 5lbs.each.


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## Zen1 (May 2, 2009)

Ok, so we're going to test a drivetrain/power setup on a practice car while the real car is being made. We will use a double of one we are producing now.

We have a choice of trying on a replica ferrari f40, f50, P4, Testarossa, morgan, porsche 356 speedster, Lamborghini Countache or Mustang Eleanor. I have attached a few pictures of the cars (in various stages)
































































i'm going to china tomorrow to see headway, thundersky and a few others too. Can anybody reccommend good chinese controller and motor manufacturers?

We keep on Rolling!

Cheers,
Zen.


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## david85 (Nov 12, 2007)

So far this is the best I have found in my VERY brief search of chinese motor suppliers:

http://www.tsxdl.cn/eshow.asp?Shop_ID=250

100kw peak is a lot for such a light car, but probably not enough for 0-60 in 3 seconds. They might be able to custom build you a motor though. I have a contact there that I can ask if you want or contact them yourself.

(The motors shown here are 45-50kg in weight)


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## Jeff (Sep 25, 2008)

Zen1 said:


> Ok, so we're going to test a drivetrain/power setup on a practice car while the real car is being made. We will use a double of one we are producing now.
> i'm going to china tomorrow to see headway, thundersky and a few others too. Can anybody reccommend good chinese controller and motor manufacturers?
> 
> We keep on Rolling!
> ...


You won't find *anything* coming out of china that will put you in the three second category, that is unless you're riding on a scooter 

I recommend a Siemens Simovert 200kW AC motor/controller package, running at 600+ volts to get you there.
Call Victor at Metric Mind 503-680-0026 and ask him for pricing and delivery on this system.

DC won't do it, at least not without cutting away every spare gram of unnecessary weight, and putting ~3000A to the motor.

As far as batteries, forget about T'sky and all the other chinese prison labor made prismatic crap from China (outside of A123 Systems). They cannot deliver cells with an impedance low enough to meet your expectations, and keep you within the weight limitations required to achieve those numbers.

I know something about those goals 

Regards, Jeff


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## Zen1 (May 2, 2009)

Thanks David, and thanks Geoff.

I'm looking into both your suggestions.

Zen.


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## CroDriver (Jan 8, 2009)

I was trying to make something very similar but I just couldn't find the motor and controller that are strong enough... If you want AC motors -> AC propulsion and UQM have some very good systems (150 kW) but they only want to deal with OEM's. Brusa has also some 100kW AC systems but they are EXTREMELY expensive.

I recently find this: http://www.evo-electric.com/products/electric-motors-and-generators-hybrid/I don't know the price of their systems but the specs look eytremly good
DC -> there are some motors out there that could handle 200kW but there are no controllers on the market AFAIK. I think that the Logisystems 156V - 1000 Amp controller is the most powerful on the market since the zillas are not produced any more...

Take a look at my thread if you want to see where I went trough the last few months... http://www.diyelectriccar.com/forums/showthread.php?t=28287&highlight=moto


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