Building a sporty EV. Need some help estimating performance.

Jayls5

100 mW
Joined
Oct 22, 2012
Messages
44
Location
Portsmouth, VA
I've been piecing together parts for a while now, and I'm in the market for a Datsun 240z as the donor car.

It will be manual transmission with a curb weight of 2300 lbs (ICE equipped). It will likely not exceed 2500 lb post conversion.

EV Parts going in:
HPEVS AC35x2 motor
Dual Curtis 1237-7601 controllers

The company lists the motor dyno performance at 96v here: http://hpevs.com/Site/images/torque-curves/ac-35x2/96 volt/imperial/AC-35X2 imperial peak data.pdf

Their dyno test sags down to 87v at ~1300A peak amp draw with whatever power supply they were running. I plan on running at least 110v nominal with a pack that sags far less so the horsepower should be higher (torque extending further up the RPM curve). The controllers easily handle 120v (and 130v max).

Basically, I'm anticipating ~260 torque & around 140 HP. Given the insane torque curves of EV's, I don't think I can trust the online "0-60" calculators that assume a ICE power curve.

Assuming traction isn't an issue, with optimally geared manual, what kind of acceleration can I realistically expect here? 0-60? 0-100?

If the performance estimates suck, I might bolt on an extra AC motor to my rear AUX shaft. I'm not the best at this type of maths. Anyone willing to help me crunch some numbers? :mrgreen:
 
Everyone has a different idea of sporty, but a single AC35 in a 400lbs motorcycle feels pretty gentle, from my own dyno session with an AC35 the site that sells them has some pretty optimistic dyno charts.
 
liveforphysics said:
Everyone has a different idea of sporty, but a single AC35 in a 400lbs motorcycle feels pretty gentle, from my own dyno session with an AC35 the site that sells them has some pretty optimistic dyno charts.

Sporty is relative, true.

Well, Here's my AC20 build weighing about half what the 240z will weigh, running ~103v nominal:
https://www.youtube.com/watch?v=W7qHHbTEPa0

That's working with about 80 ft-lbs of torque according to the company's graphs. The AC-35x2 has 3.2x the torque, so I was really hoping to get a 5-6 sec 0-60 time in the Datsun. Doable?
 
Hey, Where are you located?

I am a current Z owner (1x 240z, 1 x 280zx) both are still ICE.
What exactly are you wanting to achieve? The torque of the electric motors can give you some good launch. But only if you choose the right motor, controller and batteries.

My experience has been that a fair battery pack givin 500amps at 170v in a 1600lb car with a full gearbox gives slightly better than ICE 240z acceleration up to about 45mph. But then the ICE 240z would beat it from 45mph up. But that is OK by me because my EV is only designed for sub 60mph performance. To achieve higher speed I would need to increase my voltage requiring mre batteries and more weight which is not what I need.
My cars performance can be seen by googling "Full Charge Motorsport"
It is using around 70KW of power in a car half the weight of a 240z. So I think you need to be aiming for about 150KW or better (real achievable power, not an optimistic sales specification). Plus you will want to run something like 300V to get the top end power.

Weight is everything with EVs. If I were tryign to achieve a fast road legal EV I would be looking more towards a clubman/7/caterham or even an MX5. The caterham chassis might be a little more expensive but you'll save money on the batteries, motor, controller required to achieve the same performance.
 
I think your target is about right but I think you need to be looking towards higher voltage than the 96v.

This site seems to indicate a 96-144v controller option
https://evolveelectrics.com/products/ac-35-motor

But I think it is too close to call. I think to be sure you would need to increase your power even more.
 
As a very basic theoretical sense-check:

1136kg car mass
6s desired acceleration time to 60mph (26.8m/s)

KE = 0.5*m*V^2 = 0.5*1136*718.24 = 407960 Joules (watt-seconds)

/ 6sec = 68.0kW *average* motor output power required for 6 seconds just to accelerate the car's mass to 60mph in 6 seconds.

That's before rolling resistance and aero losses.

Also, considering the motor will make 0kW output at zero rpm increase over the acceleration (hopefully it won't peak at 60mph...) you can see you'd need a peak rating much higher than 68kW to do what you need.


You might find Arlo's project with a Nissan Leaf powertrain interesting: https://endless-sphere.com/forums/viewtopic.php?f=30&t=63982

A big part of his project involves building a custom controller, but the main point for consideration is what a stock motor/final drive pulled from a scrap OEM EV can do. These parts are also relatively light and compact. Just a thought.
 
Just to clarify, I already own the motor (which is really two 3-phase motors built into one).

I had 1 controller already, so I ordered a second to match. I couldn't afford to buy two of their 144v controllers now.

However, the difference isn't THAT huge. The Curtis "96v" controller can safely handle up to 130v, 650A.

Assuming I build the pack to 115-120v operating range, that makes over 150 kW of input power (minus inefficiency).

I'm pretty set on the 240z for the looks, simplicity, and to finally have something all weather unlike my electric dune buggy.
 
Hi Guys
I guess im the only one here that has done real world testing with the Ac 35 x 2

First the 96 volt is a AC 34 x 2 and you wont get 140 hp

When I had the Sonic 7 running direct drive I got sub 4 second 0 to 100 kph this is with the duel AC 35 at 154 volts nominal and a pack that could give 1600 amps I actually got 1100 amps into the to controllers.
This car weigh 820 kg. We dyno this car and got 138 hp at the wheels thru the single diff.

I then put this system in my Toyota hilux with gearbox and added 2 more batteries for 160 volt nominal the controllers will shut down at 170 volt.
0 to 100 kph is around 6 seconds car weighs 1600 kg, so as gardei says weight is a factor but to get performance you need to use the torque but to do this you need a gearbox and gear changes take time.
So to get quick acceleration you need a light pack with no range that can give the amps.

Not meaning to sound like a tool with the above.

Cheers Kiwi
 
Jayls5 said:
Just to clarify, I already own the motor (which is really two 3-phase motors built into one).

I had 1 controller already, so I ordered a second to match. I couldn't afford to buy two of their 144v controllers now.

However, the difference isn't THAT huge. The Curtis "96v" controller can safely handle up to 130v, 650A.

Assuming I build the pack to 115-120v operating range, that makes over 150 kW of input power (minus inefficiency).

I'm pretty set on the 240z for the looks, simplicity, and to finally have something all weather unlike my electric dune buggy.

A Ac 34 x 2 is wound different to AC 35 x 2 and wont run very well I tried.

Cheers Kiwi
 
kiwiev said:
Hi Guys
I guess im the only one here that has done real world testing with the Ac 35 x 2

First the 96 volt is a AC 34 x 2 and you wont get 140 hp

When I had the Sonic 7 running direct drive I got sub 4 second 0 to 100 kph this is with the duel AC 35 at 154 volts nominal and a pack that could give 1600 amps I actually got 1100 amps into the to controllers.
This car weigh 820 kg. We dyno this car and got 138 hp at the wheels thru the single diff.

I then put this system in my Toyota hilux with gearbox and added 2 more batteries for 160 volt nominal the controllers will shut down at 170 volt.
0 to 100 kph is around 6 seconds car weighs 1600 kg, so as gardei says weight is a factor but to get performance you need to use the torque but to do this you need a gearbox and gear changes take time.
So to get quick acceleration you need a light pack with no range that can give the amps.

Not meaning to sound like a tool with the above.

Cheers Kiwi

No offense taken. Glad to be speaking to someone with experience using the motor. My motor is definitely the AC-35x2. New in box:

LpXAuRTl.jpg

LMLBdfFl.jpg


The motor says 144v, but I purchased this second hand (unused). I've got the higher amp, lower volt controllers for it. I'll be working with ~260 ft lbs of torque instead of the ~190 torque of a 144v kit. Higher torque, lower revs. I just want to maximize the rev range on my 96v controller by doing at least 110-120v nominal and get quality batteries that don't sag. The closest useful dynograph I have to extrapolate off of is this single AC-35 motor being run at 108v:
http://hpevs.com/Site/images/torque-curves/ac-35/108%20volt/imperial%20pdf/peak%20graphs/AC-35%20108%20volt%20650%20amp%20imperial%20peak%20graph.pdf

That dyno had voltage sag to 95v. So basically, double the hp & tq of that graph. That's 258 torque, 140 hp at the motor. If you got a Hilux to pull off that acceleration with the 144v kit, I'm growing optimistic :)
 
Your motor will not run with the 96 volt controller the AC 35 is wound different to the AC 34 to make use of the difference voltage and amps sorry to be a stick in the mud.

Cheers Kiwi
 
kiwiev said:
Your motor will not run with the 96 volt controller the AC 35 is wound different to the AC 34 to make use of the difference voltage and amps sorry to be a stick in the mud.

Cheers Kiwi

If you read their section on the AC-35 motor, it was definitely designed to run on the 650A controller too:

http://hpevs.com/hpevs-ac-electric-motors-ac34-ac35-for-automotive-mining-utility-ground-support-vehicles%20.htm

That's why they bothered to do the tests at 108v & 650A with the controller I have. Do you think it's just not going to perform well because of the 0-4000 RPM useful powerband? It obviously wouldn't be good in a direct drive setup, but that's why I'll be using a gearbox. Am I missing something else here?
 
Jayls5 said:
kiwiev said:
Your motor will not run with the 96 volt controller the AC 35 is wound different to the AC 34 to make use of the difference voltage and amps sorry to be a stick in the mud.

Cheers Kiwi

If you read their section on the AC-35 motor, it was definitely designed to run on the 650A controller too:

http://hpevs.com/hpevs-ac-electric-motors-ac34-ac35-for-automotive-mining-utility-ground-support-vehicles%20.htm

That's why they bothered to do the tests at 108v & 650A with the controller I have. Do you think it's just not going to perform well because of the 0-4000 RPM useful powerband? It obviously wouldn't be good in a direct drive setup, but that's why I'll be using a gearbox. Am I missing something else here?

Designed but not wound I tried and it got hot fast you need to contact HPEV Bill with the serail number to be certain mate.

Cheers Kiwi
 
Jayls5 said:
kiwiev said:
Your motor will not run with the 96 volt controller the AC 35 is wound different to the AC 34 to make use of the difference voltage and amps sorry to be a stick in the mud.

Cheers Kiwi

If you read their section on the AC-35 motor, it was definitely designed to run on the 650A controller too:

http://hpevs.com/hpevs-ac-electric-motors-ac34-ac35-for-automotive-mining-utility-ground-support-vehicles%20.htm

That's why they bothered to do the tests at 108v & 650A with the controller I have. Do you think it's just not going to perform well because of the 0-4000 RPM useful powerband? It obviously wouldn't be good in a direct drive setup, but that's why I'll be using a gearbox. Am I missing something else here?


Missing the part where if you added a transmission to your EV project you just tripled your cruising speed inefficiency, and add a wide host of creative new failure modes that will be a hard performance potential limiter to your vehicle. It however a transmission can enable the wrong motor to make a car still function as a commuter to start on hills.

If you want the car to be fast and efficient cruising along the highway, while also being radically faster and not having transmission losses, use a LEAF transaxle with Arlin's controller. LEAF transaxles are so cheap you can likely sell the AC35's for more than you can buy a LEAF transaxle for (I've had one for $400 from a local wrecking yard).

I noticed you have a sporty emphasis and interest, which is great I'm also a fan of sporty. Accelerating a mass, no matter how light the vehicle gets, offers the opportunity for the drivetrain forces involved to approach infinite when it's accelerating it's own mass. For this reason, in something 'sporty' having extra mechanical series stages means not only friction and windage loss at each point, but also each it's own new restrictive envelope of acceptable loading forces must be obeyed, even through impulse load conditions of wheel slip, spin-up, and recovery on a sticky track.

My racecars came back on a tow strap maybe 5:1 in transmission/clutch/axle related failures vs ICE engine related failures from a point in my life before I recognized the atmosphere here is a closed loop system. Have enjoyed not experiencing a single transmission related EV drivetrain failure since, I used to joke with my old ICE buddies that no $$$ transmission/clutch drama is the real reason to get into EV drag racing.
 
kiwiev said:
Designed but not wound I tried and it got hot fast you need to contact HPEV Bill with the serail number to be certain mate.

Cheers Kiwi

Just to clarify, are you saying that there is more than one winding for the same model of motor?

liveforphysics said:
Missing the part where if you added a transmission to your EV project you just tripled your cruising speed inefficiency, and add a wide host of creative new failure modes that will be a hard performance potential limiter to your vehicle. It however a transmission can enable the wrong motor to make a car still function as a commuter to start on hills.

If you want the car to be fast and efficient cruising along the highway, while also being radically faster and not having transmission losses, use a LEAF transaxle with Arlin's controller. LEAF transaxles are so cheap you can likely sell the AC35's for more than you can buy a LEAF transaxle for (I've had one for $400 from a local wrecking yard).

I noticed you have a sporty emphasis and interest, which is great I'm also a fan of sporty. Accelerating a mass, no matter how light the vehicle gets, offers the opportunity for the drivetrain forces involved to approach infinite when it's accelerating it's own mass. For this reason, in something 'sporty' having extra mechanical series stages means not only friction and windage loss at each point, but also each it's own new restrictive envelope of acceptable loading forces must be obeyed, even through impulse load conditions of wheel slip, spin-up, and recovery on a sticky track.

My racecars came back on a tow strap maybe 5:1 in transmission/clutch/axle related failures vs ICE engine related failures from a point in my life before I recognized the atmosphere here is a closed loop system. Have enjoyed not experiencing a single transmission related EV drivetrain failure since, I used to joke with my old ICE buddies that no $$$ transmission/clutch drama is the real reason to get into EV drag racing.

Acceleration forces are dependent on time, and I'm more than willing to add a few tenths of a second by programming in parameters to ease drivetrain strain. I've already got the OEM Curtis programmer, which is very robust. If there's any slop in the transmission, going from zero load to max torque can mean gearbox destruction. I can program away the violent forces that my drivetrain can't handle, kind of like how Tesla is doing by pre-loading their gearbox to minimize damage jarring forces on launches. A little bit of knowledge goes a long way. I can hear the slop in my VW Gearbox with my AC-20 that made me put in an acceleration ramp to ensure longevity.

I was most worried about the clutch. In either case, I'd love to use a badass single gear drive setup like Arlin, but I don't want the programming headaches of sensor/sensorless transition start judders that he only recently conquered after endless tinkering, and I don't even think it would fit in a RWD setup anyway.
 
You're right that you can get it to function reliable by making it apply weak forces with gentle force ramps to the drivetrain parts. I guess we just have radically different ideas of sporty.

Leaf transaxle with the controller assembly removed from it sits at roughly the normal height of a cars rear differential.

Since you're free to copy Arlin and he has it figured out now, that's quite handy you don't have to figure it out, because I agree he has put an epic amount of RnD and circuit redesign and tuning to arrive where he is today.

You can also design and construct an inefficient, complex/clunky, and gently accelerating EV and just call it sporty, which is also fine and I wish you the best on it.
 
Jayls5 said:
kiwiev said:
Designed but not wound I tried and it got hot fast you need to contact HPEV Bill with the serail number to be certain mate.

Cheers Kiwi

That is what I was told from HPEV but please check it may have change this was 3 years ago.

The HPEV motors are relatively a plug and play and you have the motor, you still need a gearbox adapter. When I did my 0 to 60 mph test I left it in 2nd gear. Normally I leave it in 3rd gear to drive around its certainly not clunky.
I do run a Toyota racing clutch and a LSD diff, the main problem I have is gearbox torque twist.

BTW it craps all over a nissan leaf speed and range I have a nissan in the area and have compared performance, mate cars are a very individual choice if you want do a 240 do it and learn and have fun on the way, I think everyone on ES does this every day.
Cheers Kiwi
 
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.
 
liveforphysics said:
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.

Yes I agree we are currently doing a Tesla 420Kw motor swap for a client but can't post any details as the client would like privacy, but lets say it will be fun and quick.


Cheers Kiwi
 
kiwiev said:
liveforphysics said:
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.

Yes I agree we are currently doing a Tesla 420Kw motor swap for a client but can't post any details as the client would like privacy, but lets say it will be fun and quick.


Cheers Kiwi


Bad ass Kiwi!!! Thrilled to hear it! The future is so bright for hotrods.
 
liveforphysics said:
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.

I suppose I should mention that this was always a budget build. I paid about half of what the kit costs & already had the programmer. It's admittedly not ideal because money.

I know that once the motor is on, it's a pretty decent platform for an upgrade in the future as cheaper A/C induction controllers become available.

The motor's 6500 rpm rating is continuous; it's listed as 10k capable on their retailer's website. It's a common topology 4-pole asynchronous A/C motor, so I think there's a good chance of a hacked OEM EV controllers working with it in the future. If I managed to get 200v capable controllers with the same current rating, that's a healthy 400 hp to work with at around 8k RPM. I'm not sure how much efficiency gets sacrificed as you go higher in voltage, but if I can burst the same 1300A for 255 torque up to 10k RPM... that would make a pretty quick Datsun.
 
Jayls5 said:
liveforphysics said:
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.

I suppose I should mention that this was always a budget build. I paid about half of what the kit costs & already had the programmer. It's admittedly not ideal because money.

I know that once the motor is on, it's a pretty decent platform for an upgrade in the future as cheaper A/C induction controllers become available.

The motor's 6500 rpm rating is continuous; it's listed as 10k capable on their retailer's website. It's a common topology 4-pole asynchronous A/C motor, so I think there's a good chance of a hacked OEM EV controllers working with it in the future. If I managed to get 200v capable controllers with the same current rating, that's a healthy 400 hp to work with at around 8k RPM. I'm not sure how much efficiency gets sacrificed as you go higher in voltage, but if I can burst the same 1300A for 255 torque up to 10k RPM... that would make a pretty quick Datsun.

Go for it mate I have the programmer too it is real handy, just watch the motor temps

Good luck

Cheers Kiwi
 
liveforphysics said:
kiwiev said:
liveforphysics said:
Unlimited paths to winning at EVs and all if them offer enriching life experiences. Genuinely wish you the best with your project, I am just chomping to see the next evolution in DIY EV swaps happen, but nothing wrong with taking a tried and true approach.

Yes I agree we are currently doing a Tesla 420Kw motor swap for a client but can't post any details as the client would like privacy, but lets say it will be fun and quick.


Cheers Kiwi


Bad ass Kiwi!!! Thrilled to hear it! The future is so bright for hotrods.


Cheers mate

I'm in love with Aflo 1 could really have a play date with this Guy he is doing things I only dream of.

Cheers Kiwi
 
Hey Jay

Jehu is doing a range test with a HPEV AC-50 using a 1239 Curtis controller to suit the packs he has so maybe you can swap controllers

Cheers Kiwi

[youtube]xMoTLXmZoz4[/youtube]
 
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