[brightsparkz]

Hi All,

I have been meaning to build a electric car for some time, and figured the most straight forward approach would be to convert an existing car than building a car from scratch. I wanted a small car, which had readily available spares and importantly looked cool. I settled on the Classic Mini.

I have been collecting parts for some time, currently have an 8in Advanced DC (ADC) motor, a coupe of lynch 200 (LEM) and some Lynch 170 motors. I had been debating which motor to use, either the large ADC motor or two LEM motors in the front subframe. To get the torque required at the wheels I would build a simple gear reduction most likely using the gear reduction in a standard differential.

Last week I stumbled over a classified where someone was selling parts from a prototype car, all the parts I needed for the conversion. The parts included a Yasa motor that made direct drive to the wheels possible, and Sevcon inventers (Gen 4, S8). I figured it was worth a shot using these parts so I made the deal and they are currently now in my garage (gulp!).


So now I better start designing! The idea is to modify the existing mini subframe to accept the two Yasa motors, and drive the front wheels via direct drive. For me to test the inverters I wanted to build a solid base to mount the motors so I will be modifying the mini frame first.


I have attached a pic of one of the motors in the subframe, you forget how small the mini is, the subframe is tiny or the motor is massive! With some mods I think I can get the output shaft of the motor to align with the hole in the subframe for the drive shaft. I will be designing the motor, inverter, coolant pump mounts in CAD and most likely get them laser/plasma cut. Saves me time (I have a 5 month old I need to play with).

Once I have the motors mounted, the next step would be to get the inverters working. I have done some research on the inverters, and can see that getting them to work will be a challenge. They were modified to work in a particular way in the prototype and I doubt they will work in my set up as they are. To modify the programming it looks like I will need a USB to CAN interface and special Sevcon software - this part is going to be the most challenging part (I think). ie getting the software and learning how to work with CAN.

Anyway, this will be a long and slow journey (the mini wont be slow though) so pls check back in to see progress. Anyone that can help me with getting the Sevcon inverters to work, drop me a line!

 

[coleasterling]

So it was you! I'm quite jelly.

 

[brightsparkz]

So it was you! I'm quite jelly.

Don't be jelly yet, i'm not sure if any of it works!

 

[MalcolmB]

Wow! This is going to be fun. That layout with side by side pancake-format motors driving the front wheels directly has always been my ideal for a mini conversion, though I imagined using slightly less powerful motors...

I don't know of anyone in the UK who supplies the Sevcon software and IXXAT USB to CAN adapter, but I've had a little contact with this French company before and they do sell it: https://evea-kartmasters.fr/en/cont...can-compact-v2-intelligent-can-interface.html
I know this adapter works with the Sevcon Gen 4 Size 6 controllers, but you'll need to check that it works with Size 8 as well.

Do you know what application the motors were originally used in? If the controllers are already preconfigured then it should at least provide a starting point to work from, even if it's not ideal for your mini. From what I understand the most difficult part is programming the controller with the motor characteristics, and that part should already have been done.

It looks like you'll need to remove some of the rear web from the subframe to move the motors back a little, but as you doubtless know the steering rack limits how how far back you can go. It might give a bit more clearance if you raise the motors a little above the normal driveshaft centreline.

Will definitely be following your progress!

Malcolm

 

[brightsparkz]

Hi Malcolm.


I know I can get the IXXAT USB to CAN adapter much more cheaply on ebay, just this weekend one sold for £100. The issue is that they are all V2 and i may need a V1 since the Sevon controller is pretty old. I think the V2 does work but there are compatability issues with the Sevcon software. Also i have found very little online about the size 8, most people use the smaller versions. I figured i would modify the subframe to fit the motors and inverter and then i can start testing it to see if it would work using the basic wiring diagram (long shot). If not i would have to get the adaptor and software and start modifying settings.


The motor worked with the inverter in the past so in theory the motor/inverter programming should be already done.


Its a bit tight in the subframe, well spotted i will have to remove a bit of the subframe at the back and make sure the motor does not hit the steering rack. it will be tight but think it can work. Hoping to model it all in CAD first. I think the CV joints can take a fair bit of misalignment but i'm going to try and minimise it as much as possible.

 

[coleasterling]

I've wanted to purchase and build and N600 for years and your project is very similar to what that would be.

I think I would start with all the components on the bench and see if you can't get them wired as they would have been in the prototype. I think you should have all the pieces? Did it come with the throttle? That will let you sort out the wiring diagram for the car, too.

 

[brian_]

I have attached a pic of one of the motors in the subframe, you forget how small the mini is, the subframe is tiny or the motor is massive! With some mods I think I can get the output shaft of the motor to align with the hole in the subframe for the drive shaft. I will be designing the motor, inverter, coolant pump mounts in CAD and most likely get them laser/plasma cut. Saves me time (I have a 5 month old I need to play with).

Once I have the motors mounted, the next step would be to get the inverters working...

I understand the importance of getting the motors mounted to be able to run them, and that there are limitations on how the motors can be located, but have you considered how their mounting will work with other components?

One potential advantage of this dual pancake motor configuration is that there should be room between the motors. In a small front wheel drive car not designed to accommodate a battery, it would be good to be able to one pack of battery modules in the front, and that could be between the motors... but is the battery module design known yet?

 

[coleasterling]

I understand the importance of getting the motors mounted to be able to run them, and that there are limitations on how the motors can be located, but have you considered how their mounting will work with other components?

One potential advantage of this dual pancake motor configuration is that there should be room between the motors. In a small front wheel drive car not designed to accommodate a battery, it would be good to be able to one pack of battery modules in the front, and that could be between the motors... but is the battery module design known yet?

Brian,

Part of the problem with those motors is that they don't have back plates and are designed to be bolted together. Not a huge problem, but he'd have to have individual back plates machined for each motor to be able to split them.

 

[brian_]

Part of the problem with those motors is that they don't have back plates and are designed to be bolted together. Not a huge problem, but he'd have to have individual back plates machined for each motor to be able to split them.

YASA's product page for the 750 shows front and back plates (perhaps needing only a cover at the shaft), but of course the motors can be purchased in various configurations. Unfortunately the photos from the classified ad (and the discussion which preceded it) are now gone, so I can't see what these motors look like on the back.

Looking at the original transaxle, it appears that these motors will need to be installed back-to-back anyway to get roughly original axle shaft lengths. I don't know how much shorter the relatively narrow-track Mini could tolerate.

 

[coleasterling]

YASA's product page for the 750 shows front and back plates (perhaps needing only a cover at the shaft), but of course the motors can be purchased in various configurations. Unfortunately the photos from the classified ad (and the discussion which preceded it) are now gone, so I can't see what these motors look like on the back.

Looking at the original transaxle, it appears that these motors will need to be installed back-to-back anyway to get roughly original axle shaft lengths.

Those *specific* motors, not the Yasa 750 in general. It is pretty much just a cover.

 

[MalcolmB]

It might be worth reaching out to this guy to see if he can offer any advice as he's also using a Yasa motor with Sevcon size 8 controller: https://youtu.be/NCa6sS_Sk0M

 

[brightsparkz]

I've wanted to purchase and build and N600 for years and your project is very similar to what that would be.

I think I would start with all the components on the bench and see if you can't get them wired as they would have been in the prototype. I think you should have all the pieces? Did it come with the throttle? That will let you sort out the wiring diagram for the car, too.

The motors are pretty big and i should really secure them before testing. I may as well mount them in the subframe and test then as in both scenarios (testing on the bench vs in subframe) i'll have to make similar parts.

 

[brightsparkz]

YASA's product page for the 750 shows front and back plates (perhaps needing only a cover at the shaft), but of course the motors can be purchased in various configurations. Unfortunately the photos from the classified ad (and the discussion which preceded it) are now gone, so I can't see what these motors look like on the back.

Looking at the original transaxle, it appears that these motors will need to be installed back-to-back anyway to get roughly original axle shaft lengths. I don't know how much shorter the relatively narrow-track Mini could tolerate.

I plan on having the motors back to back, definitely not enough space between them to fit batteries. I think there is a cooling benefit there too since both motors will see the same coolant.

 

[brightsparkz]

It might be worth reaching out to this guy to see if he can offer any advice as he's also using a Yasa motor with Sevcon size 8 controller: https://youtu.be/NCa6sS_Sk0M

Thanks for that Malcolm, will definitely try and get in contact!

 

[pickmeup]

Great to see another classic mini project in the making, Im organising a stand at the IMM in bristol showcasing EV conversions alongside the new BMW EV. Be good to see you there!
Will be keeping an eye on this thread as i havent seen this setup used before.

 

[Tremelune]

Any photos?

 

[brightsparkz]

Great to see another classic mini project in the making, Im organising a stand at the IMM in bristol showcasing EV conversions alongside the new BMW EV. Be good to see you there!
Will be keeping an eye on this thread as i havent seen this setup used before.

Hi, would like to come but will have to confirm nearer the time. Ideal place to buy mini parts!

Any photos?

None yet, will hope to get parts drawn up on CAD this weekend so hopefully can share more then. All i have right now is a pile of parts.

 

[Tremelune]

hope to get parts drawn up on CAD this weekend so hopefully can share more then.

That would be fantastic!

 

[brightsparkz]

Hi All,

I mentioned in my first post that the pile of parts were from a OEM prototype car that was built around 2012. When I bought the parts I was also given a lot of files inc CAN messages and block diagrams. I am currently looking through the files and discovered the below block diagram showing PDU HV connectivity so the CAN links are not shown but the inverter, charger, battery, and vehicle management unit (VMU) are. I have all the parts other than the VMU, and this is a problem as the throttle input goes from this VMU to the inverters. Do you think it would be too much of a challenge to develop a VMU of my own? I'm a mechanical engineer so pretty clueless with controls but I pick things up quickly. The other option is to reprogram the inverters to run on analogue input and not link the components through CAN but I will lose a lot of the functionality and safety features of the current design. What do you think?

 

[brian_]

I am currently looking through the files and discovered the below block diagram showing PDU HV connectivity so the CAN links are not shown but the inverter, charger, battery, and vehicle management unit (VMU) are. I have all the parts other than the VMU, and this is a problem as the throttle input goes from this VMU to the inverters. Do you think it would be too much of a challenge to develop a VMU of my own?
...
The other option is to reprogram the inverters to run on analogue input and not link the components through CAN but I will lose a lot of the functionality and safety features of the current design. What do you think?

Given that there are separate left and right motors, I think it would be difficult to build a sufficiently capable control system, unless you have substantial ability to add programmed functionality to the motor controllers. For example, Curtis Instruments has controllers which are designed to be able to communicate and to coordinate control of two motors, so one takes the analog accelerator pedal input and serves as the control master, while the other controller gets its commands from the master and acts as a slave; each controller powers a motor. The intelligence needs to be somewhere, and if that's not the motor controllers I think you need a VMU.