# Electric Miata Project



## dcb (Dec 5, 2009)

nice lightweight choice, very popular, good chance of finding a bolt-on transmission adapter.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=miata site:evalbum.com


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## procupine14 (Mar 17, 2010)

Yeah I'm pretty sure that an adapter plate for the trans should be pretty easy. And from what I'm seeing, unless there cheaper/better options, I'm thinking of a AC50 motor from Curtis. I think it should handle anything I'm willing to throw at it.


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## Duncan (Dec 8, 2008)

Hi procupine
If you are looking to use Leaf batteries - why not use the Leaf power unit as well?
(in the back in place of your diff)

Later Leafs may be a bit too tall (they have the inverter on top of the motor)
but an earlier model should be OK


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## procupine14 (Mar 17, 2010)

Duncan, this is something that I've considered, I'll need to do some further measurement to see if I can fit it. My main concern is whether or not I have the 20" of room required between the suspension sides.

I've actually watched a teardown of a Leaf and, to be honest, I think even a 2013 can have its inverter/charger etc, removed from the top of the motor/trans stack and relocated with relatively minimal tweaking.

Most of my concern was just with how much cutting/welding/swearing getting the 12x19x20 motor/transaxle in there.

Custom axles would be required, but I have some machinist friends that can handle that part for me, most likely.

What I really need, is a drive unit that I can get really good measurements off of for mocking up.


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## Duncan (Dec 8, 2008)

Hi Procupine

As somebody who fitted a Lancia engine/gearbox in my old mini in the 80's I would say that you WILL be able to make a Nissan Leaf power unit fit!

I suspect that you would find the end result much better than an AC50 - and you may be able to replace the "brain board" to get a LOT more power later

It's worth putting your location on your sign in - here (NZ) getting hold of Leaf bits is difficult - but if you can get Leaf batteries then I expect that a motor unit would be easy - and cheap as nobody wants these (yet)


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## procupine14 (Mar 17, 2010)

OH that's very good to hear.

I can probably snag a salvage Leaf with all the bits (albeit a bit of damage) for a few thousand USD if I'm lucky.

I think there's actually a couple less than 300 miles from my doorstep in working but not drivable condition.


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## procupine14 (Mar 17, 2010)

Alright, I'm resurrecting this thread with some questions. For simplicity sake, and keeping most of the stock Miata intact, I've decided to pop an adapter plate on the stock transmission. 

That being said, I'm still thinking of using a pack from a Leaf as well as possibly the HVAC and a few other bits as I find them.

All that being said, I've taken some time to really think about my requirements or what I'd want out of this conversion. Ultimately, I want it to still be a fun sports car. In that same vein, I'd really love it to make more power than it does stock (the ICE in it currently is pushing around 170 hp). Along with this, I'd also really like to have regenerative braking as a way of mimicking the natural engine braking that exists in the car in stock form.

All that being said, I have a few starting questions. I know that some PM DC motors are capable of regen. However, I haven't found a ton of information about what controllers support this or whether there's a significant amount of extra work required to facilitate this. Should I just shoot for AC propulsion or is DC with regen possible? 

My other question centers around power. I think I can pull off my power requirements handily with something like the Warp9 and a 144V pack (if my math is accurate, possibly not?) Keeping with the above question, can I actually pull off regen with the Warp motors (and again which controller)? If I'm better off going AC, what kind of motor/controller would get me close to this power level? Admittedly, I'm still struggling with how the power "feels" versus output in an electric car vs ICE so it'd be nice to see some numbers to help me out here.

Thanks guys!


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## brian_ (Feb 7, 2017)

procupine14 said:


> I know that some PM DC motors are capable of regen.
> ...
> I think I can pull off my power requirements handily with something like the Warp9...


Did you really mean PM DC motors? That would be a brushed DC motor with a permanent magnet stator; that's common for stuff such as small fans, but in my limited exposure to the EV world I've ever heard of one sized to drive a car.

A Warp 9 - or an old forklift motor or any of the many other similar motors - is a brushed DC motor with a series wound stator... not PM.


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## procupine14 (Mar 17, 2010)

brian_ said:


> A Warp 9 - or an old forklift motor or any of the many other similar motors - is a brushed DC motor with a series wound stator... not PM.


I may have gotten my wires crossed a bit on which was which (no pun intended). 

Yeah, you're right about the Warp 9. I was reading up on NetGain's newish Hyper9 motor which is a PM motor.


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## riba2233 (Apr 29, 2015)

Yeah but it's not DC motor, it's 3 phase AC with magnets on the rotor.


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## brian_ (Feb 7, 2017)

procupine14 said:


> Yeah, you're right about the Warp 9. I was reading up on NetGain's newish Hyper9 motor which is a PM motor.





riba2233 said:


> Yeah but it's not DC motor, it's 3 phase AC with magnets on the rotor.


True; I assume that the original reference to a PM DC motor (regardless of brand or model) was intended to be PM AC. Actual PM DC motors are rare in a size suitable for a car, if they exist at all.

Yes, AC motors (both PM and induction) can be used effectively for regenerative braking.


WarP motors are brushed series DC
Hyper9 is PM synchronous 3-phase AC (usually just called PMAC)
Nissan Leaf motor and all other current production EVs other than Tesla Model S and X are PM synchronous 3-phase AC
AC-50 (and this entire line of "AC-" motors) is 3-phase induction AC (usually just call induction)
Tesla Model S and Model X are 3-phase induction AC
While the AC-50 and other motors of the same line are commonly sold with a Curtis controller (from Curtis Instruments), and these motors are sold by several vendors including HPEVS, it appears that the motor is manufactured by or for HPEVS; they are not Curtis motors (Curtis makes controllers, not motors).


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## procupine14 (Mar 17, 2010)

Thanks for some of that clarification all. I'm still kind of new to this so I'm just kind of wallowing through documentation. I'm thinking that I'll probably pursue some sort of AC setup then as I'd really like to gain regen on this build. 

That being said, my question now is about power. I'm having a bit of trouble thinking in terms of power in the electric motor space as opposed to ICE. Would anyone have a suggestion on what combination would get me to something that feels close to 200hp from an ICE engine?

Really appreciate any recommendations you all have on that. I'm guessing it's mostly down to the controller as my understanding is that most traction motors are pretty robust in terms of how much amperage you can push through them.


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## Kevin Sharpe (Jul 4, 2011)

procupine14 said:


> Would anyone have a suggestion on what combination would get me to something that feels close to 200hp from an ICE engine?


I'd start by looking at the Tesla 'small' motors... they're rated at ~250HP and will probably deliver a lot more 

The inverter has been 'hacked' and an open source controller is available (here). It will run at 'low' voltage and a 250V pack seems perfectly feasible (10 Tesla Model S Modules might be an option if range is important to you). You will also do away with the transmission, clutch, and differential, that some early conversions retained 

You can see the rough size of the 'small' rear motor (here), the 'small' front motor is very similar in size but sits more upright. We have multiple conversions using the Tesla drivetrains and other components in progress at this time, so lots people to help if required


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## procupine14 (Mar 17, 2010)

Oh wow, that's pretty impressive! I'd be thrilled to do away with all of that complexity and just have some axles fabricated. 

Looks like I have some reading to do. Do you happen to know the weight of that "small" assembly?


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## Kevin Sharpe (Jul 4, 2011)

procupine14 said:


> Do you happen to know the weight of that "small" assembly?


small rear is 88kg, small front ~84kg with the acoustic covers removed 

You can see a little more detail in the photos here


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## procupine14 (Mar 17, 2010)

Well I'd say that's pretty reasonable! This may be how I make things happen for this project. I'm going to go off and read a bunch about this and see what I can make of things. I'll post back with any questions I may have.


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## Kevin Sharpe (Jul 4, 2011)

procupine14 said:


> Well I'd say that's pretty reasonable!


iirc the Tesla drivetrain is half the weight of the ICE/Transmission/Clutch/Axles that I removed from the VW Bus... oh, and power went from ~35HP to ~250HP


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## Kevin Sharpe (Jul 4, 2011)

procupine14 said:


> I'm going to go off and read a bunch about this and see what I can make of things. I'll post back with any questions I may have.


I think Damien's E31 will be the first to roll with open source Tesla power... my bet is he'll have ~650HP available from the Tesla 'large' drivetrain 

See here for more...


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## procupine14 (Mar 17, 2010)

After looking at the open source controller you linked, I'm definitely thinking it's something within the realm of things I can do with some study. First and foremost, I need to work on sourcing a drive unit that isn't $10,000. Time to go hunting!


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