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Discussion Starter #1
Dear colleagues,


as suggested by fellow forum-member brian_ in the new members introduction, I will start a thread for my EV-Conversion of a 1954 Renault 4 CV. For those of you who are not familiar with this nice little french car (rear engine and RWD), here's a picture together with its great-granddaughter Zoe, who is already fully electric and won't need any surgery ;-):





My plan is to document the whole conversion process here step by step.


With this first post I'd like to give you an idea on the rough lines of the conversion. My plan is to keep as much of the originality and driving dynamics of the original car as possible. This will mean that some key values will have to stay within a band of +/- 10% of the original car, e.g. power output in KW and weight. I might make an exception for torque though ;-)


Also for the same reason I want to keep the clutch and gearbox, with the added value of some "classic" feedback and noise. This will be the main difficulty on this car, as the flywheel/clutch assembly is integrated into the engine, so the gearbox comes without a bell housing... so there might be the need to fabricate a custom solution there. I will talkt to you later about that and include some specific pictures for better understanding.


But to start with the simple things, here you can see how easy it is to separate the drivetrain from the chassis on this type of car:





For the technical details, here's my rought plan:


Battery System:
4 x Tesla Modules in 4s configuration, most probably one in the petrol tank compartment, two in the back and one in the front.

No decision yet on the BMS and charger.


Motor:
FIMEA Engineering N50D1, 15KW @96V, 140 Nm of torque, 7500 rpm max.





Controller:
Curtis or Sevcon, tbd.


Looking forward to all your questions, comments or suggestions - I might also have some questions for you too while moving along!


Best regards,
Remi (R4eCV)


PS: Not sure if any of you ran into a similar problem: I had originally written a much longer text as the one above, but once I got to submit it, the system had logged me off and I lost all of my work. Note to self: The next time I will preparte the text offline and then paste it into the forum!
 

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Keep the gearbox / clutch is probably not the best idea.
What about reuse a complete drivetrain of an i miev / peugeot ion?
Or another transmision if this is simpler. My Smart fortwo use a VW golf transmission without clutch and I can drive only in third gear from 0 to 100 km/h. I ususally use 2e in town and 3e at highway.

Anyway, this is a nice little car and good luck with your project.
 

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My Smart fortwo use a VW golf transmission without clutch and I can drive only in third gear from 0 to 100 km/h.
If the operating range of the motor is wide enough, driving in a single gear is practical... after all, that's how production EVs work. If the transmission is not shifted while driving (because one of the stock gear ratios - presumably first or second - is suitable), the clutch is not required... and without the clutch, the flywheel is also not needed.
 

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Discussion Starter #4
Hello Yabert and brian_


Thanks a million for your replies and for your thoughts about the transmission setup.


There are three main reasons why I want/need/should keep the original gearbox/clutch assembly:


1) The main philosophy/strategy of the conversion. I want to keep everything as close as possible to the original. This includes driving dynamics, feedback, noise and even some "sluggishness" of the response of the drivetrain. Also, all changes must be reversible (at least in theory).


2) Local technical regulations for Motor Vehicle Testing in Switzerland: As long as I limit the changes to an "Engine Swap", the testing process is somewhat overseeable (I still wouldn't say easy though). Bigger changes will call for a complete re-homologation of the vehicle, which leads to tremendous cost (in excess of $5'000) just for the testing and certifications. Also, other upgrades (e.g. braking system) will be needed, which would completely alter the character of the car as per bullet 1).


3) I am living in the middle of the Alps, with steep mountain passes over 2'000 metres of height. On a car with such low power (15KW) the possibilty to adjust the power band of the motor through a gearbox can be very welcome in some situations, resulting in less amps and therefore less strain on the system, including batteries.


So for these reasons, the original gearbox is set.


I went down the other road already to check other options. E.g. I had a complete drivetrain of a Renault Twizy on hand, which would have been in the target values as well with a Letrika/Mahle motor with 13 KW. But it just doesn't fit in with the selected conversion strategy, especially regarding originality and reversibility.


Hope you understand where I am coming from
.


Will post some updates regarding gearbox asap, just need to find out which is the best option to include pictures in this forum. In my first post I tried to link to external sources, just found out here that we can also attach some pictures, will try it with this post just to see how these images would show up in the thread....


Best regards,
R.
 

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Motor:
FIMEA Engineering N50D1, 15KW @96V, 140 Nm of torque, 7500 rpm max.
I found a manufacturer's web page for the N50 motor series, but it's short on information. Do you have any performance curves, showing how available torque or power varies with speed, at your design voltage? The rated power values at all voltages and speeds correspond to torque well below the stated maximum torque, so it's not clear if the power is continuous and the torque is for a brief period, or the torque peak is at a much lower speed, or what is going on.

It does look like a heavy motor for the power, perhaps only because it doesn't (in the base form) have any forced cooling. It should be possible to use a smaller motor with forced cooling; if a suitable motor is more powerful than desired, it should be possible to limit the power to suit legal requirements by a controller setting.
 

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With that nearly flat engine-side housing plate (where there would normally be a cast extension of the housing or a bolt-on bellhousing), the transaxle certainly is unusual... but this design is so old that the conventional layout was not yet well established. This feature does raise the possibility of replacing that plate with a custom mounting plate for the motor (and a clutch if desired).

The transaxle's input shaft presumably protrudes a substantial distance beyond the housing, to reach into the clutch hub. That means that any motor mounting needs to include a spacer (a function normally provided by the bellhousing), unless the motor has a hollow shaft allowing the motor to mount over the shaft instead of beyond it. YASA makes motors which would fit well, but they don't have anything small... their P400 is much more powerful (and therefore expensive) than required.
 

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Discussion Starter #7
Hello brian_

Again thanks a million for your thoughts.

Regarding the motor options: I am well aware that there would probably better options available worldwide. But in addition to the strict power requirements, the vechicle testing department of my local authority also requests the motor to come with full documentation on CE-certification, EMV compliance and so on. This rules out all the likes of e.g. HPEVS motors, which would be much lighter. The Fimea motor has been successfully used here, e.g. in the conversion of a Mini, and are therefore certified to be used as traction/conversion motors. As it is mounted in the back of the car, the cooling could be a bit of an issue, so maybe it's not even the worst option even seen from that angle.

As said, my favourite would have been the Letrika AMV 7122.

I have been in touch with the owner of the converted Mini who confirmed that the Fimea is a very good motor with a good performance curve. I don't have the full documentation here with me at the moment but will be glad to share it as soon as I can.

For the clutch bell housing I am currently working on the CAD for the transfer case between the motor and the gearbox. Will also share it here asap to get your thoughts on it.

Thanks again & best regards,
Remi.
 

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Discussion Starter #8
Btw - this is the front side view of the actual gearbox with the protruding input shaft:



Best regards,
Remi.
 

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... in addition to the strict power requirements, the vechicle testing department of my local authority also requests the motor to come with full documentation on CE-certification, EMV compliance and so on. This rules out all the likes of e.g. HPEVS motors, which would be much lighter. The Fimea motor has been successfully used here, e.g. in the conversion of a Mini, and are therefore certified to be used as traction/conversion motors.
That's certainly an important factor. :)

As it is mounted in the back of the car, the cooling could be a bit of an issue, so maybe it's not even the worst option even seen from that angle.
Given the desire to stay close to original where practical, I assumed that you would place any required radiator (whether it is cooling the battery, inverter, or motor) in roughly the same location as the original radiator, which appears to be over the axle. The complete electric powertrain should need less cooling than the original engine.
 

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For the clutch bell housing I am currently working on the CAD for the transfer case between the motor and the gearbox. Will also share it here asap to get your thoughts on it.
Btw - this is the front side view of the actual gearbox with the protruding input shaft...
It really does look like a typical transmission, but with no bell housing installed. Fascinating...

If you don't modify the input shaft, its length plus the length of shaft protruding from the motor sets the minimum length of the bell housing / spacer required, and a flywheel will add to that.

If you don't need a clutch, and if you are willing to modify the transaxle input shaft, and if the input shaft doesn't need support at the end... you could cut off much of the protruding shaft length and build a coupler which goes onto the remaining splines, reducing the length of the housing and how far back the motor must sit.
 

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With that nearly flat engine-side housing plate (where there would normally be a cast extension of the housing or a bolt-on bellhousing), the transaxle certainly is unusual...
This feature does raise the possibility of replacing that plate with a custom mounting plate for the motor (and a clutch if desired).
Btw - this is the front side view of the actual gearbox with the protruding input shaft...
So it looks like the sensible plan would be to design the bell housing or other extension to seat on the machined face and bolt through the provided holes (where the engine bolts to), leaving the transaxle case intact... especially if you're operating a clutch, but even if eliminating the clutch and thus not needing the throwout bearing and fork.
 

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... and if the input shaft doesn't need support at the end... you could cut off much of the protruding shaft length and build a coupler which goes onto the remaining splines, reducing the length of the housing and how far back the motor must sit.
The great length of the non-splined part of the transaxle input shaft suggests that it does need support - presumably from a very long or very deep-set spigot bearing in the end of the crankshaft.
 

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Discussion Starter #13
Hello colleagues

it is always a good sign when my ideas match with the suggestions from you experienced guys!

My plan is to build a transfer case to house the flywheel and the clutch assembly.
The transfer case would consist of two round aluminium adapter plates (not sure yet of the required thickness, I started with 15 mm for now), each plate with the specific bolts (for gearbox or motor respectively) on an inner ring and the holes for connection bolts on an outer ring. I would like to mount the gearbox-side adapter plate on top of the existing machined cover as seen on the previous picture.

In between the two adapter plates I would insert a cylindrical tube of 5mm Aluminium, held in place by a milled groove on the inside of the two adapter rings, and bolt everything together on the outer rings.

Here's my first sketch of my idea:







What do you think of this concept guys?


Thanks & best regards,
Remi
 

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The great length of the non-splined part of the transaxle input shaft suggests that it does need support - presumably from a very long or very deep-set spigot bearing in the end of the crankshaft.
Yes, there's a good chance of that, but it's also possible that it only needs support if the is the clutch disk hanging on it.

An internal drawing of the transaxle would help.
 

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My plan is to build a transfer case to house the flywheel and the clutch assembly.
The transfer case would consist of two round aluminium adapter plates (not sure yet of the required thickness, I started with 15 mm for now), each plate with the specific bolts (for gearbox or motor respectively) on an inner ring and the holes for connection bolts on an outer ring. I would like to mount the gearbox-side adapter plate on top of the existing machined cover as seen on the previous picture.

In between the two adapter plates I would insert a cylindrical tube of 5mm Aluminium, held in place by a milled groove on the inside of the two adapter rings, and bolt everything together on the outer rings.i
That looks to me like it should work (as long as the bolts don't interfere with the transaxle housing); an alternative would be to use weld the adapter plates to the tube... skipping the clamping bolts entirely. For this welded fabrication to work, one set of bolts (presumably the ones on the transaxle side) would need to be accessible outside of the tube; if both sets of bolts (into the motor and into the transaxle) are inside the tube, then it must be a two-piece housing to be able to assemble everything.
 

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Discussion Starter #16
I have checked with a first printout if it would work on the front plate with the bolts and it looks pretty good to me (you can see the outline of the gearbox cover plate on it):



So I will most probably pursue that way. It will take a while as I'll need to identify a good machine shop... I have none on hand at the moment, so will have to investigate further.

But will look into some other stuff in the meantime. One question that comes to my mind: Are there standard boxes for Tesla modules available or do I need to design them from scratch too?

Thanks and best regards,
Remi.
 

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Are there standard boxes for Tesla modules available or do I need to design them from scratch too?
I think you're starting from scratch. Although Tesla (like every other EV manufacturer) sees the need for an extensive and substantial enclosure, many DIY builders think the plastic cases on the modules are fine, so they don't put in them in a proper enclosure... there's not even agreement on what level of enclosure is needed, so with every conversion having different packaging requirements, there's no market for a standardized enclosure.
 

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Discussion Starter #18
Thank you brian_!

Will look in the battery section if I can find some good practices on battery enclosures. I absolutely agree on the need of a proper enclosure, especially for the underfloor modules, but also in the motor compartment, as they would be exposed to some extent.

I can see that you seem to have a great knowledge in EV conversion there, and you got me intrigued: Would you like to share the link to your projects with me so I can have a look at your own stuff too?

Cheers,
Remi.
 

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I have 1980 Renault le car (lecric leopard)

It has torsion bar suspension as i believe yours dose

The previous owners brother said it was lowered with just a wrench

Its so low cant get in or out of driveway

Any easy way to raise it back at least a few inches???

Thank you
 

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I have 1980 Renault le car (lecric leopard)

It has torsion bar suspension as i believe yours dose...
I don't think the Renault 4CV has any suspension parts in common with a Renault 5 / LeCar; you're probably thinking of the Renault 4, which is much like a 5 / LeCar but very different from a 4CV.
 
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