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Discussion Starter · #1 ·
Hi Everyone,

I planning an EV conversion for a Riley Elf but as far as I can tell this setup would work on any classic mini.

I am very early in the planning stage and I don't currently even have a car yet.

The forum has been a good start for learning what goes into an EV conversion but I am by no means an expert in fact I'm clearly a novice.

I have been trying to space out and plan the build using AutoCAD by using scaled 2D drawings I have found for the Elf, subframes, motor and shell. This clearly has its limitations and ideally I would like to get my hands on a scanned mini shell.

I am planning on using the SWIND HPD E 80 motor as this is such a small unit that mounts nice and low in the engine bay. I plan on either using a modified front subframe with mounting points for a battery box above the motor or by using a subframe similar to the design of the B-TEC tubular frame conversion.

This should allow for enough space for a battery box that will hold 8x CALB modules. This may require the inner wings to either be cut back or removed to allow for the width of the box. This will also require the radiator and fan to be mounted in the front grille, vertically for the Elf or horizontally for a normal mini grille.

I chose the CALB 6P2S for their voltage as the motor is 400V and this set up gives the most voltage over the LG version or the 4P3S CALB.

There will be a further 4 or 5 modules in another battery box in the rear subframe. This will require strengthening of the rear subframe and also the boot floor panel to be cut out and a flat panel to be welded in to remove the 12V battery box and spare wheel well. Potential to use a modified mini van rear floor panel.

This means that I should have total battery energy capacity of 26.6 kWh and a nominal voltage of 266.4V.

The controller, DC/DC converter are yet to be decided. I have found the Cascadia PM100DX for an inverter but am open to other options as the costs are starting to escalate by this point. They, along with the charger will be hidden in a fake fuel tank in the boot, this will allow for all them to be located directly underneath the filler neck.

I am looking at the potential of using two Tesla gen 2 charger to give a fast charging capacity of 20 kW. I don't currently have a place to park and charge the mini so would most likely be doing street charging hence the need to be able to charge quicker.

All connections from front to rear will be via exhaust tunnel so no HV inside the cabin.

I think additional weight / balance should not be too affected as the rear weight is over the wheels and nice and low. The front battery box (96 kg) and motor (50 kg) are not much more than the presumed weight of the a series & gearbox.

So what do you guys think? Any advice about this setup would be appreciated.

Cheers,

Jon

Proposed Mini Battery Layout Black.PNG
Proposed Mini Battery Layout White.PNG
 

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That all makes sense, except for the inverter location. From the fuel tank location to the motor is extremely long for inverter to motor cables. Doesn't Swindon offer a suitable inverter to go with the motor, and set up to mount with it?

It also seems unlikely that the PM100DX (200 x 87 x 314 mm, 5.5. L), a Zero EV 1 kW DC-to-DC (290 x 159 x 73 mm), and two Tesla chargers will fit in the fuel tank space, assuming that it is something like the Mini tank.

I chose the CALB 6P2S for their voltage ...
I assume that this is just a typo, and you meant 6S2P (which would make more sense and is shown in the drawings).
 

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Discussion Starter · #3 ·
Hi Brian thanks very much for your feedback and yeah that was a typo.

I wasn't aware that the inverter to motor distance was a factor but I do also have my doubts about fitting all those components in the fuel tank area so I will look at relocating the inverter up front.

Out of interest what is the reason for them needing to be close together?

Swindon offer the PM100DX as an add on option but theirs is mounted to the side of their add on battery box which has a capacity of 12 kWh and costs a whopping £16k. Also with the current layout of the CALB modules I don't think there is going to be room for me to mount the inverter on the side without fouling the wheel arch. I think there is potential above the subframe mounts along the bulkhead but its just guesswork without a 3D model to play around with.

swind.jpg
 

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I wasn't aware that the inverter to motor distance was a factor...

Out of interest what is the reason for them needing to be close together?
Without looking at it in detail, I have always assumed that long cables cause problems due to cable inductance. Industrial VFD cables can be very long but they're typically running at only 60 Hz, while EV motors typically run at several hundred hertz or more at high vehicle speed. In very practical terms, shielded 3-phase cabling is more expensive than unshielded DC cabling, so it helps to keep the AC side short even if that makes the DC side longer.

The Cascadia inverter manual isn't very specific, saying only:
"The motor wires are the most likely to generate EMI and they also carry a higher average current than the DC power wires. When installed in the vehicle these wires should be kept as short as possible. It is also recommended that shielded wire be used for the motor wires."​
 

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Suggestion
At the rear throw the back subframe away - just make a cross bar that is mounted to the front mountings for the subframe - this would carry the bearings for the swinging arms
Beef up the rear wheel arches and use coil springs on the shocks for the suspension

This will free up a lot of wasted space for batteries

As an old "Mini Man" I thought long and hard about making an electric mini - one of the reasons that I did not go that way was rust

In the UK in the 80's there was a fiberglass kit car - the Domino Pimlico

If I was still living in the UK I would have tried to get hold of one


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1971 Mini Marcos, Outlander Meiden Motor, Meiden Inverter
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nice to see another mini conversion in the making, especially a riley elf. Ive owned a wolseley Hornet which is very similar.
Swindon Powertrain sell the subframe and driveshafts too, which i would contemplate to make the install easier. But of course this is an added expense, but i think you have made a great start by planning out all the parts.
Im way behind on my conversion and i might actually change from the marcos to my mini scamp as i can use it as a test bed (mule) and then transfer and improve the conversion.

Be wary of cutting and modifying the boot floor as this could cause any issues with the DVLA, you really dont want to go down the IVA route.
 

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That Swindon drivetrain ain't at all cheap, and it ain't all that powerful either. McGee's Custom Minis has a prototype subframe that fits a Honda gearbox and Hyper9 motor that you might want to look into. If you're any good at fabrication (or know someone who is), it's not all that hard to fit a (superior) Leaf motor and inverter up front (though you lose battery space, and your top speed is limited by your tire diameter).

With regard to CALB batteries...Perhaps I'm not up to speed, but I'm almost certain you'll get better energy density and performance for less money by using an OEM battery pack out of a Leaf, Tesla, or Bolt. Are these cars rare in your part of the world?

The Mini can handle plenty of weight in the rear, either by using stiffer cones (Yellow Spots) or by adding "helper" coilovers in addition to the cones that are there. The downside is that a FWD car with a heavy ass may not go around corners the way you want it to...

I will tell you that a tiny British EV is extremely fun to drive around town, and I've had very few issues with mine since I started driving it.

Edit: I see Swindon is now selling smaller component packages that seem priced pretty well. Nice!
 

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For charging, BMS, and DC/DC, it's worth looking at Thunderstruck's stuff:


I've had good luck with their products, and they're priced competitively vs other aftermarket stuff.
 

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With regard to CALB batteries...Perhaps I'm not up to speed, but I'm almost certain you'll get better energy density and performance for less money by using an OEM battery pack out of a Leaf, Tesla, or Bolt.
CALB is well-known in this forum for their prismatic LiFePO4 cells, but probably not for their modules.
In case anyone is not aware of these specific modules, CALB is building them of 12 pouch cells in the VDA 355 format, in either 6S2P or 4S3P configurations. Either way they're 2.2 kWh in 5.8 L and 12 kg. I don't know that the chemistry is, but based on the 3.65 V/cell nominal voltage they're not LiFePO4. The energy density is better than the commonly used LG Chem 16S modules (which are used by the Chrysler Pacifica Hybrid). Of course they'll be more expensive than salvaged modules, because they're new.
 

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Nice to see another coming Mini-conversion. And looks well planned, too.
I think it is a good approach to leave good weight on the front axle, otherwise the tremendous torque will be wasted.
I agree with brian: keep the inverter close to the motor.

And very funny to see the Pimlico here: it was the base of a really early professional EV-conversion made by genius EV-pioneer Andreas Klasen:

In the 90ies, you could order one of these for approx. 20000,-- DM. Note the problem at those times: battery weight and life expectance. This car was the first inspiration for my EV-Mini. Took me 20 years to realize it.

Jon, looking forward to your project!
Markus
 

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Discussion Starter · #11 ·
Hi Duncan, just want to say I'm not having a go at your suggestion, but that it doesn't fit my project design criteria. I have come across the beam axle when researching for this project. It's not the path I want to be going down as it is only really intended for extreme weight loss for track and fast road minis to take as much weight out of the rear to get lift off over steer in the corners, creating a "skittish" handling characteristic. I am not going to be using my Elf on the track, its mainly going to be used for short city trips or the occasional weekend getaway/blast/car show. This mean that I don't really need anymore than the 22kW of batteries. Zero EV get around 100 miles out of their 26kW pack in their MX5 so I should get around 120 miles in the lighter mini with 22kW. The 'wasted battery space' is actually unnecessary additional weight and the subframe is needed to support the battery box.

I have changed my mind on the charger set up after seeing the new 'Tech talk with Chris' video from Zero EV.
these videos along with their MX-5 build have been invaluable for me as a novice. I will be using CCS and a 3.3kW charger, this will allow for normal charging of around 7 hours or rapid charging of around 30 minutes. This also means I'll be going with Orion BMS.

Hi Tremelune, I think that the hyper 9 Honda combo sacrifices to much space in the engine bay that can accommodate batteries. I also have no need for the extra power of the Hyper 9, the Swind is still giving more than double torque and 1.5x the hp. Also goes back to my point about it being predominately a city car. The CALB modules were chosen to get me up towards the 400V of the motor and also because the are able to be arranged in lots of different orientations. I have also heard that they're industry standard size meaning future replacements should be a straight swap.

Hi pickmeup, as the mini boot floor normally rusts away I'm hoping that it won't need an IVA if I'm replacing it anyway during the conversion.

Thanks everyone for your feedback
 

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Hi Duncan, just want to say I'm not having a go at your suggestion, but that it doesn't fit my project design criteria. I have come across the beam axle when researching for this project. It's not the path I want to be going down as it is only really intended for extreme weight loss for track and fast road minis to take as much weight out of the rear to get lift off over steer in the corners, creating a "skittish" handling characteristic. I am not going to be using my Elf on the track, its mainly going to be used for short city trips or the occasional weekend getaway/blast/car show. This mean that I don't really need anymore than the 22kW of batteries. Zero EV get around 100 miles out of their 26kW pack in their MX5 so I should get around 120 miles in the lighter mini with 22kW. The 'wasted battery space' is actually unnecessary additional weight and the subframe is needed to support the battery box.

I have changed my mind on the charger set up after seeing the new 'Tech talk with Chris' video from Zero EV.
these videos along with their MX-5 build have been invaluable for me as a novice. I will be using CCS and a 3.3kW charger, this will allow for normal charging of around 7 hours or rapid charging of around 30 minutes. This also means I'll be going with Orion BMS.

Hi Tremelune, I think that the hyper 9 Honda combo sacrifices to much space in the engine bay that can accommodate batteries. I also have no need for the extra power of the Hyper 9, the Swind is still giving more than double torque and 1.5x the hp. Also goes back to my point about it being predominately a city car. The CALB modules were chosen to get me up towards the 400V of the motor and also because the are able to be arranged in lots of different orientations. I have also heard that they're industry standard size meaning future replacements should be a straight swap.

Hi pickmeup, as the mini boot floor normally rusts away I'm hoping that it won't need an IVA if I'm replacing it anyway during the conversion.

Thanks everyone for your feedback
Hi
There are two beam axle designs - one is an actual beam axle - and you are correct that is a track racing mod

The design that I was suggesting is not as extreme!
You basically use the "beam" to replace the front of the rear subframe - and continue to use the usual rear swinging arms

I take claims of high mileage with a small shovel of salt!
Back in the old lead days lots of people claimed mileages that were three or four times the actual mileage

My Device - with its awful aero - uses 14 kwh for about 50 km at 100 kph - so 100 miles (160 km) out of 26 kwh may involve a little "hype"

This was my old mini -
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Hi Duncan, just want to say I'm not having a go at your suggestion, but that it doesn't fit my project design criteria. I have come across the beam axle when researching for this project. It's not the path I want to be going down...
As he explained, Duncan didn't suggest a beam axle at all, only changing the subframe. Much of the Mini rear subframe (grey in this photo) is there to accommodate the stock rubber or hydrolastic suspension units, and to distribute the load along the vehicle structure:


If you change to vertical spring/shock units (coils on telescopic dampers/shock absorbers), you can replace the big subframe with something simpler just across the front of the space, but the vertical load will be concentrated at wherever you mount the tops of the shocks:

In the above example, the stock trailing arms are replaced, but the replacements are still simple trailing arms (connected by a stabilizer bar).
 

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Zero EV get around 100 miles out of their 26kW pack in their MX5 so I should get around 120 miles in the lighter mini with 22kW.
I think that's very optimistic. Even if it is lighter, the Mini will have higher aerodynamic drag. The 260 Wh/mile value for Zero EV's MX5 might be plausible (although it is better than many production EVs using state-of-the-art technology and developed in billion-dollar programs), but to expect to use only 183 Wh/mile (a 30% reduction) is likely unrealistic.
 

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Hi Jon, very interested to see your ideas. I started looking at converting an MG Midget, but then "accidentally" ended up restoring a Rover Mini. I too had been looking at the Swind mini conversion, and how expensive their battery is. I am also looking at EV-zero batteries as a cheaper and upgradable suggestion. Have you spoken to Swindon yet? I am planning to call them next week, and ask them some questions. I will let you know if I find out anything useful.
 

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Discussion Starter · #16 ·
OK I see, sorry Duncan I understand now, so would roughly gain the width of the rubber cones on either side for more batteries. Seems like a decent possibility but it does provide less mounting points for the battery box. Thanks for clearing up Brian.

Boatman, I haven't spoke to them yet, my project is nowhere near that stage but any information you can share is always welcome. As I mentioned right a the top I don't see why the layout wouldn't work in a standard mini instead of an elf.
 
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