# Classic Mini Electric Conversion



## McGeesCustomMinis (Oct 26, 2020)

It seems I won't be the first, and certainly not the last. My name is John and I have been building Classic Minis for a little over 11 years. 3+ years ago I developed a Honda Sohc Kit to convert the Mini to Honda power. This included a bespoke subframe, header, axles, intake manifold, clutch adapter, standalone harness, etc. While this has proven successful I am looking to expand our range in 2021 and the EV peaked my interest because I saw an easy way to convert my existing kit to work with the Hyper 9d Motor. So my plan is this:

*Parts:*
1. Our Bespoke Subframe
2. D-series transmission, EX trans with 3.25 final drive, lightened flywheel, possibly Mfactory LSD
3. CANEV Adapter Plate
4. Hyper 9D 100v Motor
5. Our custom clutch adapter (honda master to work with stock pedals)
6. Our custom hybrid shafts (honda to mini outer cv)
7. Mount for motor and controller (hyper 9D) to D mount
8. OX batteries, or (5) Tesla Model S batteries
9. Elcon UHF 3.3kw Charger, or 6.6kw Charger
10. Elcon 1000W DC/DC Converter
11. Orion BMS 2 Kit - 36 cells max

*Goals:*
-1600-1750lb total weight
-125+ Mile Range
-120hp/180torque

*My concept:*








*What I already do:*


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## McGeesCustomMinis (Oct 26, 2020)

*Question*, using the EX or HX D trans with 3.25 final drive... I assumed leaving it in 3rd gear for most scenarios would suffice, however, with the Hyper 9, what RPM do you want to be maxed out at? 4500 RPMS? If so that would be around 60mph hour. If that is the cause, shifting to 4th for highway use to stretch it out a bit more to drop the revs on the motor that seems it would cover the gambit. Is my logic right?


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## ev-swap (Jan 31, 2020)

Wow, that is an amazing looking replacement kit. I can only imaging how excited a mini owner would be to pop the hood and show off that Honda motor setup.

I know I'm not answering your question about the Hyper 9 RPM, but have you considered a Tesla small drive unit instead of the Hyper 9? I think there would be some great advantages.
1) simplicity. The Tesla small drive unit (SDU) has the motor, invertor and transaxle all in one neat, tidy package.
2) Power: they are capable of 300 hp out of the box if your batteries can deliver the juice
3) Costs: I know its not fair to compare a new Hyper 9 to a used part, but the SDU can be found all day long for $3K or less on ebay (condition unknown) or $7K from a dealer with a warranty. And bear in mind that that cost covers the motor, controller and transaxle.
4) smaller package: I am guessing that the SDU is smaller than the existing transmission plus Hyper9 motor and controller, which could be a consideration in a 'mini'.
5) no tranny issues: I rode in a saab that had been converted using a hyper 9 AC and the regen braking was slowly eating the transmission from the inside out. It was designed to take torque from the motor to output shaft, but regen braking applies torque the other direction and the transmission was not happy at all. I'm not sure if the mini tranny would have that issue, but it sure would be nice to just delete the whole tranny/clutch/shifter if possible.

Cons:

Custom axles would be required
higher battery voltage requirement for the SDU than the Hyper 9
dealing with the unknown of eBay for the drive
DIYing an opensource controller from OpenInverter or paying a premium to HSR/EVWest/EVControls/StealthEV/PolyKup, etc. for one.

Since you are going to manufacture your own subframe, it seems like it might be worth the time to build one just for the SDU.

Just food for thought. Mike


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## McGeesCustomMinis (Oct 26, 2020)

ev-swap said:


> Just food for thought. Mike


Mike, I understand what your saying, and I value the input. But here is my thought process. My subframe I have already done the R&D on for the past 3 years, and have sold over 60 of them thus far. So without going too far down the rabbit hole and starting a completely new build from scratch, it is using a tested frame, axles, clutch adapter, etc. The only real development I need to do is 1. Additional motor mount for opposite trans side to accept the D-series mount which would also integrate the controller in 1 unit ideally. I like the thought and simplicity of using the D-series trans. We have worked with Syncrotech Tranmissions for years and their product is great and they can build them how we like them. It seemed like a lot of builds that are direct drive, or using OE setups are limited by Tire size and RPM. 65mph top speed is not bad, but having the option to row one more gear to get to.... 75... 85.... on the freeway sounds appealing and still makes you interact with the car a bit (atleast in my mind). Atleast in most areas I am surrounded by. I don't want to be in the right lane with my 998cc Mini engine hanging on. And your cons list rings true to me as well. Not sure how the Saab trans is, and if he left it stock, built up, etc etc. We have built a few 164WHP, 130 Torque at the wheels and she did just fine.


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## McGeesCustomMinis (Oct 26, 2020)

I goofed up on running the calcs. I meant to run the CX/VX gearbox with 3.25 final drive. Simulation running 4500rpm and 6000rpm. Even at 4500rpm, looks like in 3rd gear it will get it done for most scenarios. Thoughts?


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## Tremelune (Dec 8, 2009)

You'll be fine either way. Many EV conversions that retain the stock manual transmission do as you describe: Around town in 2nd, highway in 3rd or 4th. I think the Hyper9 does 8k RPM max, so you'd mostly be limited by how fast the gearbox can spin.

You can also ditch the clutch, but that means you _kinda_ have to be stopped to shift, which nobody likes...one less thing to bleed every 2 years, though!


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## brian_ (Feb 7, 2017)

Tremelune said:


> You can also ditch the clutch, but that means you _kinda_ have to be stopped to shift, which nobody likes...one less thing to bleed every 2 years, though!


Or, to go without a clutch, the controller can be programmed to match the motor speed (and thus input shaft speed) to what it needs to be in the gear that the driver is shifting into. Nobody does that, only because almost nobody designs EVs (other than amateur conversions and paid conversions of amateur quality) with multi-speed transmissions.


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## McGeesCustomMinis (Oct 26, 2020)

I guess getting back to my question, obviously if you had one gear you would be limited by motor rpm. Being that I'd have multiple gears to take advantage of, where would you want to be shifting at motor rpm wise? Certainly you wouldn't want to run the motor up to 8000 rpms? Am I looking at this wrong?


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## wjbitner (Apr 5, 2010)

McGeesCustomMinis said:


> I guess getting back to my question, obviously if you had one gear you would be limited by motor rpm. Being that I'd have multiple gears to take advantage of, where would you want to be shifting at motor rpm wise? Certainly you wouldn't want to run the motor up to 8000 rpms? Am I looking at this wrong?
> 
> View attachment 120745


Since you have the torque curve and the gear ratios, I'd make a spread sheet with the torque at the wheels in each gear. You can choose your shift points by when the next gear has more torque than the previous gear (maybe make the cells above 8000 a very low torque, so it will always be better to hit the next gear above 8K). You'll also get some idea of the vehicle performance since you'll have torque at the wheel numbers. Then you can run this with several different motors to see what fits your performance and $$..


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## brian_ (Feb 7, 2017)

wjbitner said:


> Since you have the torque curve and the gear ratios, I'd make a spread sheet with the torque at the wheels in each gear. You can choose your shift points by when the next gear has more torque than the previous gear (maybe make the cells above 8000 a very low torque, so it will always be better to hit the next gear above 8K).


You can do that, but it's easier to just shift to stay within the range in which maximum power is available. Torque is power divided by speed, so for any given road speed, the motor speed which provides the most torque is the speed which provides the most power.


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## brian_ (Feb 7, 2017)

McGeesCustomMinis said:


> I guess getting back to my question, obviously if you had one gear you would be limited by motor rpm.


Yes. The normal approach is to choose the overall gear ratio so that the motor is at its maximum speed, or the highest speed at which it can produce the required power, when the vehicle is moving at the highest design speed. Like everything else in design this is a compromise, since a taller ratio potentially allows a higher speed, but it also reduces the power available at low speed (in the region in which the motor is limited by set current and resulting torque output).



McGeesCustomMinis said:


> Being that I'd have multiple gears to take advantage of, where would you want to be shifting at motor rpm wise?


Typically modern motor and controller combinations have a common set of performance characteristics:

At low speed the motor current is limited, by controller current capacity and/or motor heating issues, so a constant current limit leads to a constant torque output. For the HyPer9 as shown in the graph, that applies up to about 3400 RPM.
As speed increases the motor power is limited, by battery power output capability, controller power-handling capacity and/or motor heating, so a constant input power limit leads to a constant power output. For the HyPer9 as shown in the graph, that is about 80 kW and applies from about 3400 RPM to 6000 RPM. In a typical production EV, much higher battery voltage extends this range (to about 10,000 RPM in a Leaf, for instance).
At some point battery voltage is insufficient to push enough current, and power drops off. For the HyPer9 as shown in the graph, that occurs at about 6,000 RPM.
Eventually either zero current, torque, and power are reached due to the limited voltage, or mechanical considerations such as bearings become limiting. For the HyPer9 as shown in the graph, the test ends at 8,000 RPM but the motor is still producing lots of power, so it is a controller frequency limit, a mechanical limitation, or just the end of the test range.
I consider any performance data published by NetGain to suspect, because there are too many strange inconsistencies to give me any confidence... but the one posted above is sensible.

The best motor speed would be determined by power availability and efficiency. For power, the obvious choice is to just stay anywhere in the power-limited speed range; that's 3400 to 6000 RPM in this case. Efficiency depends on speed and load: anywhere in the power-limited range is probably reasonable, but within that range a greater load (torque, power) is probably most efficient at a somewhat higher speed, and best efficiency occurs at a moderate speed and load. There is an efficiency map in NetGain's marketing material for the HyPer9; it is a generic chart for the range of motors and is probably not correct for the HyPer9, but it shows the general behaviour.

The net result is with typical compact production car manual transmission gearing, the top ratio is pointless. Just shift up at 6000 RPM from first and by 6000 RPM from higher gears, and shift down when motor speed drops to 3400 RPM, and you'll have full power available from whatever 3400 RPM in first corresponds to... and you'll never make it to a speed that requires shifting out of 4th. You can use a short final drive ratio for better performance at the lowest speeds; if that makes fifth gear useful it also means smaller motor speed changes between gears... which you don't need. With a higher-voltage motor like a production EV, this gets to the point of never needing to shift at all, but the HyPer9 is a deliberately low-voltage motor made for industrial vehicles.

The HyPer9 was supplied to NetGain, along with suitable controller, by SME Group of Italy (who in turn built them - or had them built - in China), but SME was purchased by Dana (the truck axle people) last year, and placed in their TM4 division (TM4 was another motor manufacturer which they bought earlier). I think this product is now Dana TM4's SRI 200 line... and most of the published information has evaporated, but SME never did publish anything about the specific version that they supplied to NetGain. If anyone has the manufacturers performance data, that would be interesting to see.



McGeesCustomMinis said:


> Certainly you wouldn't want to run the motor up to 8000 rpms? Am I looking at this wrong?


While running anything at the very limit of any rating is probably not generally a good idea, the efficiency shown in the HyPer9 graph is essentially the same (at full load) at any speed above about 2500 RPM... probably including well past 8000 RPM if the controller and motor can go there. The SRI 200 line is rated up to 9000 RPM, which probably (but may not) apply to all models.

With an internal combustion engine you would certainly avoid high speed to reduce mechanical stress, wear, and efficiency loss due to high fluid (air and exhaust) flow. None of those factors apply to an electric motor, although there is some issue with aerodynamic drag due to air in the gap between the rotor and the stator.


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## Tremelune (Dec 8, 2009)

Great post! How did you know about the Dana acquisition?


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## schelle63 (Jan 3, 2018)

Dana Acquires Nordresa, Industry-leading e-Powertrain Integrator - Aug 26, 2019


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## schelle63 (Jan 3, 2018)

It seems DANA is further investing in electric drive.


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## schelle63 (Jan 3, 2018)

Dana Acquires SME Group, Enhances Electromobility Capabilities and Global Reach - Jan 15, 2019


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## brian_ (Feb 7, 2017)

Tremelune said:


> How did you know about the Dana acquisition?


I had run across that acquisition when looking for information on the SME products a while ago, forgotten about it, and was reminded when I found the same press release when looking for an efficiency map from SME for the HyPer 9 this time. Similarly, I had run across the TM4 acquisition when looking for an update on TM4's motors. It helps for context if you are already aware of Dana's products - most people are not unless they are interested in trucks or 4X4's.


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## McGeesCustomMinis (Oct 26, 2020)

Thank you all for the input. I'll post as things progress. Cheers.


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## McGeesCustomMinis (Oct 26, 2020)

Took the plunge last week and purchased Hyper 9 dual shaft 100v Motor, Controller, Chill Plate, CanEV D Series Adapter, Chromoly Lightened Flywheel and Clutch, and a few other odds and ends. I'm getting ready to build a 92-95 VX Transmission with 3.25 final drive. Already have a subframe built up. Should be a fun winter project.


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## brian_ (Feb 7, 2017)

McGeesCustomMinis said:


> Took the plunge last week and purchased Hyper 9 dual shaft 100v Motor, Controller, Chill Plate, CanEV D Series Adapter, Chromoly Lightened Flywheel and Clutch, and a few other odds and ends. I'm getting ready to build a 92-95 VX Transmission with 3.25 final drive. Already have a subframe built up. Should be a fun winter project.


All good news... but why a motor with a double-ended shaft (which is what I assume you meant by "dual shaft motor")? What would you want to drive from the encoder end of the motor... air conditioning?


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## McGeesCustomMinis (Oct 26, 2020)

brian_ said:


> All good news... but why a motor with a double-ended shaft (which is what I assume you meant by "dual shaft motor")? What would you want to drive from the encoder end of the motor... air conditioning?


I wanted the double ended shaft to offer a better bracket mounting solution then to require customers in the future to hack into the case and add studs. Just seemed like a more straight forward solution to hang a bracket from that side with mounting options. Motor should be here next tuesday. CanEV sent out the adapter plate, but still no work on timeline, but hopefully soon.


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## zrickety (Dec 4, 2020)

Sounds great, subscribed.


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## McGeesCustomMinis (Oct 26, 2020)

Few Parts arrived a few weeks back, just catching up on the thread now while I have a minute.


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## McGeesCustomMinis (Oct 26, 2020)

I had a spare built up frame that we build for a customers 64 Mini we are getting ready to build.


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## McGeesCustomMinis (Oct 26, 2020)

Then more parts started to trickle in, and started designing some other bits while waiting for other parts. Lightened flywheel, clutch, pressure plate showed up.


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## McGeesCustomMinis (Oct 26, 2020)

Started getting it mocked up in the frame, and got all the suspension bits to throw together. Waiting on right side bracket that I sent to laser cuter to show up and start playing with that.


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## McGeesCustomMinis (Oct 26, 2020)

Finished up prototype header and intake manifold for our D series conversion. Tossed those on there to see how they look. HA!


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## brian_ (Feb 7, 2017)

McGeesCustomMinis said:


> Then more parts started to trickle in, and started designing some other bits while waiting for other parts. Lightened flywheel, clutch, pressure plate showed up.
> 
> View attachment 121231


Is the starter ring gear coming off of that flywheel, or is it integral to the flywheel (instead of the usual shrink-fit)?


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## McGeesCustomMinis (Oct 26, 2020)

brian_ said:


> Is the starter ring gear coming off of that flywheel, or is it integral to the flywheel (instead of the usual shrink-fit)?


Unfortunately it is part of the flywheel, and obviously useless.


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## McGeesCustomMinis (Oct 26, 2020)

Adapter plate milled out, pretty stoked with how it turned out. The brackets I designed should be here tomorrow night from the laser cutter, hope to get the front clip assembled by mid next week.


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## brian_ (Feb 7, 2017)

McGeesCustomMinis said:


> Adapter plate milled out, pretty stoked with how it turned out.
> ...
> View attachment 121555
> 
> ...


I'm confused. There is an adapter plate in the photos from a month ago, and it does not appear to be this one... so what was that one?

Also, that's really thick - presumably to suit the motor shaft length - and solid; was the extra material just left to reduce machining time? I assume that there is no steady bearing in this design.

Does the shaft coupler incorporate a pilot bearing for the nose of the transmission input shaft?


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## McGeesCustomMinis (Oct 26, 2020)

brian_ said:


> I'm confused. There is an adapter plate in the photos from a month ago, and it does not appear to be this one... so what was that one?
> 
> Also, that's really thick - presumably to suit the motor shaft length - and solid; was the extra material just left to reduce machining time? I assume that there is no steady bearing in this design.
> 
> Does the shaft coupler incorporate a pilot bearing for the nose of the transmission input shaft?


Brian, adapter plate originally was from CANEV, and it was always meant to be a place holder for me. I didn't like how it was clocked with the Hyper 9 and sat the connections on the back. When I made my motor mount I drilled 2 sets of holes, one for the CANEV adapter, and one for my projected new one that was clocked the way I wanted it to be. Yes the coupler incorporates the pilot bearing. Yes it is thick to suit the length of the shaft. As far as extra material, I played with the design and I wanted more of a cone shape to motor. The face is 1" thick, the cone portion is a bit thicker then that. We discussed various ways to produce it and keep costs down. Anyway, I should be posting more stuff hopefully early next week of it all assembled with the new parts. The shell is in primer for a few weeks now, had to finish 2 other minis before getting back on this and getting it in color. Just finished designing the Analog gauges as well.


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## McGeesCustomMinis (Oct 26, 2020)




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## OR-Carl (Oct 6, 2018)

That motor adapter and mounting arrangement for the controller looks really sharp! I take it the rotation you are trying to fix with your own adapter plate has to do with the main power inputs being at the 1 o-clock position instead of at 12? And is it correct that you went with the double-ended shaft just because the single ended one does not have bolt holes on the encoder end? Looking forward to seeing it all come together. Keep up the good work!


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## McGeesCustomMinis (Oct 26, 2020)

OR-Carl said:


> That motor adapter and mounting arrangement for the controller looks really sharp! I take it the rotation you are trying to fix with your own adapter plate has to do with the main power inputs being at the 1 o-clock position instead of at 12? And is it correct that you went with the double-ended shaft just because the single ended one does not have bolt holes on the encoder end? Looking forward to seeing it all come together. Keep up the good work!


Yes you are correct pretty much on all the assumptions. Motor was clocked somewhere between 1 or 2 o'clock, I wanted it to be at 12. And yes on the double shaft to hang it from the bracket to motor mount. That side will get a cover, although I did see someone drive an AC compressor, but I won't be getting into that... yet.


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## Tremelune (Dec 8, 2009)

Wicked. Looks like you'll have some room for a bit of battery on top of the motor, which should help with traction and weight distribution.

Have you chosen a color?


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## pickmeup (May 8, 2018)

Great work john. Some really good progress with the build and the black and grey colour scheme proposed for the car looks amazing.


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## McGeesCustomMinis (Oct 26, 2020)




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## McGeesCustomMinis (Oct 26, 2020)




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## McGeesCustomMinis (Oct 26, 2020)

Finished doing the body work this past weekend and got some color on the car after shaving the engine bay, slam panel, extra wiper holes, jet holes, dash holes, etc. I'm pretty excited, and really excited at the low center of gravity this Mini will have.


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## Toretto (11 mo ago)

this is beautiful! Any updates?


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## McGeesCustomMinis (Oct 26, 2020)

Wow, really need to add some updates. Here are a few, we are a bit further along. Had to take some breaks here and there to work on other cars, but she is getting close! Carpet got delivered today. So hopefully going to lay that in, get some seat belts in and go for a quick test drive!


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## Tremelune (Dec 8, 2009)

Well that looks quite nifty. Spacious, even. More batteries over the motor?

Tell us more about the push-button start and kill switch...


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## McGeesCustomMinis (Oct 26, 2020)

Tremelune said:


> Well that looks quite nifty. Spacious, even. More batteries over the motor?
> Tell us more about the push-button start and kill switch...


I'm going to post more pictures of the motor bay below, and this is how it will likely remain with the exception of possibly adding some inner fender liners. I personally wanted to show the mechanical components, and keep the batteries lower. As far as the push button, it has a blue tooth proximity fobs. Swipe it near steering column, press start...


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