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Working on a 1989 Classic Mini EV Conversion

12556 Views 80 Replies 10 Participants Last post by  scottherrington
Hello Everyone,

Starting work on my 1989 Mini. Thinking of keeping the original gearbox and mounting a Hyper9 motor directly on top of it. Using SilentSync sprockets and belt as a drive system. Have something similar to ´s conversion in mind. But interested in using the Hyper9 9 and some Tesla modules from the get go.

Also considering the EV Europe system:

I have no advance knowledge in EV conversions so I want to keep everything as simple as possible for this one.

Interested in getting some feedback from you guys who are the experts. Let me know your thoughts.

Am I in the right path or is this combo I have in mind a not so good Idea.

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Based in Mexico! No real worries about what I can legally do.

On the battery side, I was thinking on 5 x 5.2kWh modules. It will be a tight fit.

What are your thoughts on batteries?
Thank you all for the feedback! MAIN reason for that setup was to keep it as simple as possible.

However starting too look at different options. Keeping the subframe may be easier than a complete new setup.
Hello everyone,

Stumbled with this option online:

Size seems manageable, price wise seems similar to what I had in mind. Will the Shafts be an issue? Should I go for the limited slip diff? Using this system with other components non SWINDON could be challenging?

4,980 GBP in the config I need it, it can go up to 6,400 GBP.

Already tried the leaf alternative. It is really hard and expensive to get one of those in Mexico as there is just few of them on the roads.

With the diff ratio of 6.332, should be able to reach around 90 mph top speed.

Weight and dimensions seem ok...

Another option to contemplate I guess
This is a CAD dwg just for size reference. I just got confirmation they will be selling shafts and a subframe.

I’m really leaning into this solution.


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Thanks for the photo! @Pickmeup That’s the first time I come across the assembly.

I’m in the process of clearing out the engine bay and removing the ICE components. I do really like what they are doing at SWINDON but pretty much still open for other solutions. I think their own experimental mini is a clear example of what can be done with that 80Kw - it could clearly be used for something a bit bigger and heavier....

Being in México, using a donor car for the motor and parts is quite tricky since there’s not many of them in the market. I have also come to the conclusion that if I’m doing this conversion I might as well get rid of the old rusty parts that may limit me or give me trouble in the future (Gearbox). So I’m in between mounting a Hyper9 with a new subframe and a more modern gearbox or using the Swindon tech.

Pretty much a newbie to EV technical stuff here so I really appreciate all of the info you guys have given me and all of the useful insights I can find in other threads.

I will be updating you with progress and decisions I make.

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OK, so if I’m going with the Swindon HPD E POWERTRAIN I have a couple of options and I would really appreciate your thoughts on both topics:

1) MCU: 144V Curtis 1239 or RINEHART 400V PM100DX.

Judging from the photo they went with the PM100DX with their own Mini.

2) To include or not a Limited Slip Diff?

Meanwhile I have stripped the mini to its shell, needs some bodywork done and it will then be sent to the paint shop.


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I’m aiming for a daily city driver which I can occasionally use to drive to a weekend spot 100 miles away, charge overnight and drive back. 80 mph is the objective top speed. Will be making some changes to the mechanical side to make it a more comfortable daily, need the components to be reliable and provide the speed and performance needed for the short weekend trips. Thought the LSD could help with axle shaft/tire wear and help with traction on the “High speed” highway weekend trips.
Thanks @brian_ and @pickmeup for the info.

It’s the same 80kW motor. I will be going for the RINEHART 400V and no LSD. Battery wise I have 5 X Tesla Module 24V 250Ah 5.2 kWh in mind. Starting to draft different options on how to fit all of these in the mini.

Yes! I’m aware of this problem. I’ve been reading on this modification to the tesla modules, however it seems to be to much input and just half the solution.

Any other suggestions for this issue?
Yes! I’m aware of this problem. I’ve been reading on this modification to the tesla modules, however it seems to be to much input and just half the solution.

Any other suggestions for this issue?

These are 60V but fitting 8 of them in the mini seems tough. The form factor in the tesla modules seem more favorable.
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Different modules.

The ~60 V example is presumably the 16S LG Chem module designed for the Chrysler Pacifica Hybrid, and sold by various EV conversion companies. You would only need six for 360 V nominal; that would peak at close to the 400V inverter limit at full charge, but only give you about 16 kWh. That is typical plug-in hybrid rather than EV capacity, but might be enough for the Mini. If you can't fit in six of those, I don't know how you fit in five of the Tesla Model S/X modules (since the LG modules are only 3/4 of the volume of the Tesla modules, and the longest dimension is not much more than half as long), but what fits in is to some extent a matter of how the rigid dimensions of the modules go with dimensions of the available spaces.
Yup, thats it. 6 I could fit. Ideally I want 20kWh for the mini. I can do some fitting and weight distribution exercises with this info
Is 7-8 of these feasible with the 400V controller?
Just lowered the rear subframe this weekend. Expanding the battery bay seems doable.
I started the body work process today. Just before that, I played a bit with some fast measurements for the battery placement in case I settle down for the Tesla/Smart 18650 modules. According to the measurements I found online I settled on a nice space for 6 them, would love to have 7.

First two go side to side between the driver and passenger. I will flatten out the exhaust tunnel for this. This was done in swindons mini and the final resulta does not bother me at all. I will need to find a new place for the hand brake, for the shifter a will be using buttons on the dashboard.


The second couple of modules go underneath the rear seats, laying on their tall sides. stacked on on top of the other.
The flat floor will help, I will need to modify the support for the rear bench.


Finally. As suggested by @pickmeup I tried expanding the original battery box in the back. However this long modules wouldn’t fit with out messing with the sub. For other types of modules seems like a great solution, for me I will try to place some of the other components in there (Charger maybe?). Instead I will lay two modules next to each other and place the ”bottom“ of the trunk on top of them, I should have a good amount of available space in the trunk.


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Scanales: You can add considerable space under the rear seats by cutting out the seat's support panel and reinstall it horizontally. You will need to ad a narrow vertical strip from left to right, and to cut out a wedge from the seat's foam. This measure is invisible, and even the rear passengers won't notice it when sitting there. I can post a picture, if required.
Thanks Markus!
Sounds similar to what I had in mind. I would really appreciate if you could share some pictures.

That’s perfect! Thanks for sharing @schelle63. I will definitely consider this mod.
Hi all,

I’ve been looking for different options regarding Air-conditioning? Some seem far more expensive than others. Wonder if its possible to use a unit from a Leaf. Want to be as efficient as possible. I saw a similar unit to the one below being installed in a EV Conversion in the Vintage Voltage show, however it seems really expensive.

Any suggestions?
Hello Everyone!

So some pretty big changes since my last post.. I’ve decided to ditch the TESLA/ SMART CAR battery packs for this project (Will definitely find somewhere to use them).

I’ve decided to go for the new OX-Drive batteries from Electric GT, also some second thoughts on battery placement and modifying the exhaust tunnel, instead, I’m entertaining the idea of having two packs under the rear seat, 1 pack on each rear side compartment, one under the bonnet and one on the trunk.

Any thoughts on this arrangement?



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21.3 kWh. It’s 6 of them. 4 back seat and sides, one in the trunk and hopefully one in the front.

No real practical motivation for keeping the rear seat. Would be nice to have, It can go if we have an issue finding space for the batteries. I thought a slight mod on the side compartments could help us gain some battery space and keep the seat, that’s all.
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