Motor options for smallish car EV conversions?

Technical discussion on converting internal combustion to electric
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OzSpider
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Motor options for smallish car EV conversions?

Post by OzSpider »

Lots of chatter about batteries and conversion kits, so building on that I'd like to tap the keg of knowledge specifically on motor options:

- Oz DIY has the AC series and others
- Netgain Hyper 9 is a common unit
- Francisco found some Kostovs but had to rewind them.
- DC options are there for really cheap conversions
- Leaf motors are coming up as a 300V option

What am I missing?
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brendon_m
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Re: Motor options for smallish car EV conversions?

Post by brendon_m »

For the more courageous folks you can go the open inverter Prius (and Camry and Lexus etc) transaxle hack route.

Or the Outlander PHEV rear motor (or front if you're really brave)
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Re: Motor options for smallish car EV conversions?

Post by jonescg »

I think raiding a crashed Leaf for it's motor and transaxle is a winning solution. A bit more mechanical engineering involved, but more elegant overall.
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OzSpider
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Re: Motor options for smallish car EV conversions?

Post by OzSpider »

Has anyone in Aus had success with the Emrax motors for a car conversion?
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Re: Motor options for smallish car EV conversions?

Post by jonescg »

None that I'm aware of. Plenty of motors have been used in FSAE cars and other small performance vehicles, but none in a road going car.
They require some specific engineering around protecting the outrunning rotor, but if you can master that the rest should be easy enough.
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Re: Motor options for smallish car EV conversions?

Post by brendon_m »

Saw the other post about your spider and you mentioned rich rebuilds rat rod. He used a Zero motorbike motor in that conversion but wrecked Zeros are hard to come by in Australia however the motor is just a Motoenergy ME1507 air cooled motor.
Didn't find a listing for the air-cooled one but here is the ME1616 which is a water-cooled version.
https://electricdriveengineering.com.au ... drive-kit/
So you can add that to the list for small car motors
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OzSpider
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Re: Motor options for smallish car EV conversions?

Post by OzSpider »

Thanks Brendon, good option, it's on the list of potentials. 👍

Still deep in the fun part of looking at all the options. With and without the gearbox.
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Re: Motor options for smallish car EV conversions?

Post by coulomb »

OzSpider wrote: Sun, 13 Jun 2021, 06:18 ... all the options. With and without the gearbox.
That's the decision we found the hardest with the MX-5. The design changed a few times from without to with. Ended up retaining gearbox and clutch.
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OzSpider
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Re: Motor options for smallish car EV conversions?

Post by OzSpider »

Thanks @coulomb read your epic build story cover to cover. Really helpful read.

The box weighs in at about 58kg with clutch and flywheel and the concept of hiding the motor in the gearbox tunnel is tempting.

A std 4.3:1 diff and lightweight car is getting me closer than most to open up direct drive options....almost.
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Re: Motor options for smallish car EV conversions?

Post by jonescg »

On the clutch issue, I found it was a wash. Engineering a drivetrain which includes the clutch is less challenging, and the whole system is a little more forgiving.
If you go without the clutch, you need a perfectly machined coupling which can be difficult with rear-wheel drives as the input shaft to the gearbox is sort of free-floating.

If you abandon the gearbox all together you will need oodles of torque, unless the diff ratio is remarkably high. 4.3 to 1 is still on the high side for most motors. Maybe an 11" DC motor would move it in a hurry?

I've been lucky that the Prelude conversion was a front wheel drive, meaning more room for batteries where the tank used to be. If there had been a tail shaft in the way, I'd have struggled to find the space. Not that the 4 wheel steering rod wasn't a pest to work around either...
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Re: Motor options for smallish car EV conversions?

Post by OzSpider »

The std drive shaft to gearbox output has a flexy donut in the driveline, called a "guibo". I'll float back to the build story for details. But I guess it's intended to dampen out either misalignment, torsional vibration or both. And that is with a clutch!

Must track down someone with encyclopedic knowledge of Fiats to work out wtf they were thinking.
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