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Discussion Starter #1 (Edited)
I’ve been lurking on here for a while. I’ve been wanting to do an EV conversion and its taken a while to find a car that I felt I would want to drive once the conversion is complete. I’ll admit from the go that, while its nice to be environmentally friendly, I feel that the finished product will have to be something that I want to drive. Some style, a bit of power and a certain “cool” factor (at least in my own head).
This car does it for me.

Skill level with auto mechanics/fabrication: I’ve restored/rebuilt a couple of cars as a teenager/early 20s. Some Minis and a Land Rover. I have minimal fabrication experience, but that’s going to improve significantly with the rust I’ll need to remediate in this.

Skill with electronics/tech. I’m a software developer working with embedded systems. I’ve got good basic electronic skills as well as being comfortable with auto electrics.

Range: I live in Santa Ana, Southern California. I’d like to be able to drive to Los Angeles and back without being too concerned about range. That would mean around 120-150 miles.
Performance: The original car had 55hp and a factory stated top speed of 71mph. 0-60 of around 30 seconds. I’d like to be able to drive on the freeway (so 80mph max). Cruise at ~70, which puts me in the slow lane around here. Some power will be nice but I’m not planning on racing it.
Budget. I figure I’ll have 15-20K in the EV components once its done. Plus restoration costs.

This will effectively be a resto mod – but one of my goals is that at a 5-10 ft range it shouldn’t be apparent that anything significant has been changed. I want to keep the essence of the car and its style.

While the exterior is in pretty decent shape, the interior is roached. The floor is completely rusted out, as well as the sills. I’m viewing this as an opportunity to build a battery tray in the floor so I can use Tesla batteries. I don’t plan on putting batteries under the hood or in the boot.

Drive train is complicated – and something I could use recommendations on. I had originally hoped to use a complete Nissan Leaf stack, but its too wide across the CV joints. I’ll add some pictures of the space I have to work with under the hood.
 

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Discussion Starter #2 (Edited)
A significant chunk of the front end sheet metal is structural, as seen in the first picture (not mine – internet sourced). I have ~325mm side to side in the engine compartment and ~500mm from the back of the engine compartment to the centerline of the CV joints. There is space forward of the CV joints that is occupied by the gearbox. I’ll get better measurements this weekend.

I’m not planning on reusing the original gearbox. It’s an 85 year old design and parts are expensive, so I'll seed to solve for transmission and diff also.

I've added an (internet sourced) image of the gearbox - showing how the bulk of its length comes forward of the CV joints. I estimate I've got about 400mm forward - so around 900mm total with the engine.
 

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The Traction Avant powertrain is fundamentally the same as generations of rear-engine cars, just sitting at the front end of the car... think VW Beetle. A practical layout may be to place the motor longitudinally ahead of the axle line (so in the location of the transmission portion of the stock transaxle), driving a final drive unit (ring-and-pinion gears and differential) in the stock location of those components. For this to work, a high ring and pinion ratio or motor suited to low speed would be needed. If someone looks under the front, the motor would look about like the transmission did.

This would leave the entire original engine space for battery modules (with electronics on top); Tesla Model S/X modules are too long but there are others. I realize that this is not the intention, but the unibody design which is one of the features that made the Traction Avant advanced is also the feature which will make underfloor modules impractical. The floor of any production EV with an under-floor battery (which is most of them) is specifically designed to fit the battery pack, with the interior floor at or above the top of the sills, in contrast to the normal practice of the floor at the bottom of the sills - that's why getting into a Tesla is like getting into a pickup truck, with the floor higher than would be expected given the door opening.

Even if you build a completely custom floor, the space available between the firewall and the rear suspension (less than 1700 mm) is very small compared to the battery case of a Tesla Model S or X, so only a small fraction of large (665 x 302 mm plus structure and housing) modules of the pack could be accommodated. That might be okay... but it's worth laying them out on that drawing (or one scaled to the actual 11B dimensions) to see how may might go in. Maybe 5 would fit?

For anyone using the handy dimensioned drawing... I believe that the 11BL would be the "11 normale" in the table on the drawing.
 

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Discussion Starter #4 (Edited)
I hadn't considered the flipped layout. I'll do some thinking on that.

regarding the drawing - the 11BL is actually the 11 Legere model. The first one in the list - so even smaller than the normale.

Update: I've edited the drawing to remove the dimensions for the other models.

Now that I've taken delivery of the car, I'll start measuring and laying out to scale.
 

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Discussion Starter #5
A practical layout may be to place the motor longitudinally ahead of the axle line (so in the location of the transmission portion of the stock transaxle), driving a final drive unit (ring-and-pinion gears and differential) in the stock location of those components. For this to work, a high ring and pinion ratio or motor suited to low speed would be needed. If someone looks under the front, the motor would look about like the transmission did.
I like this a lot. I've been researching direct drive solutions (by this I mean attaching the motor directly to the final drive/diff.

I need to find a suitably high ratio diff.
 

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regarding the drawing - the 11BL is actually the 11 Legere model. The first one in the list - so even smaller than the normale.

Update: I've edited the drawing to remove the dimensions for the other models
Oops... sorry. I realized that the 11BL was the légère, but picked the wrong column, skipping over the first one because it was headed as the "7", not reading the rest of the headings. Duh...
 

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I like this a lot. I've been researching direct drive solutions (by this I mean attaching the motor directly to the final drive/diff.

I need to find a suitably high ratio diff.
Just a thought - not checked out in detail or supported by any precedent - but there are quick-change IRS rear ends in which the input shaft runs under the axle line to a pair of spur gears on the back side. That makes the front of the housing short (so the motor could couple closely to it), and means that the final drive has two stages of reduction (the spur gear set which available in a choice of ratios, and the ring and pinion). This is an old design mostly used in oval-track racing and street rods, with long-time manufacturers such as Frankland, Halibrand, Speedway Engineering, and Winters.
 

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Discussion Starter #8
Just a thought - not checked out in detail or supported by any precedent - but there are quick-change IRS rear ends in which the input shaft runs under the axle line to a pair of spur gears on the back side. That makes the front of the housing short (so the motor could couple closely to it), and means that the final drive has two stages of reduction (the spur gear set which available in a choice of ratios, and the ring and pinion). This is an old design mostly used in oval-track racing and street rods, with long-time manufacturers such as Frankland, Halibrand, Speedway Engineering, and Winters.
Interesting. That might also give me enough room to run inboard disc brakes -- to compensate for the single leading shoe drums currently on it.
 

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I'm not sure how expensive they would be, but you could run two axial flux low speed motors direct drive - one to each wheel and utilise the two inverters as an electronic diff with torque control rather that speed control. An example motor would be the YASA400 series, but there may be cheaper options out there.
 

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One option, given the shape & size of things, would be to mount the motor vertically over where the differential is. It leaves the most space for other parts & pieces in the engine bay, and with the greatly reduced need for cooling it should be OK to effectively block most of the grill.

Just a suggestion...

RK
 

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Discussion Starter #14
Thanks for the ideas guys.

Rowan. I've been researching electric TAs for a bit to see if anyone else has done it - mainly so I can learn from them. I've found a couple references to this one previously but they're all second hand references and they all say "the south of England" Here's an example from a TA site in Australia.

http://www.aussiefrogs.com/forum/citro%EBn-forum/109870-electric-traction.html

Do you know any of the people who actually built this?

Here are a couple of youtube vids that went up:

https://www.youtube.com/watch?v=RFKNWFgBx5A

https://www.youtube.com/watch?v=1EBW-Vr6juk


These videos are dated 2013-2015, so its been done a while.


Interestingly it looks like they kept the original gearbox and mated the electric motor up to it. Common practice on a classic DIY conversion - but I was under the impression that the original box was weak. I'd be interested in talking to the builder for his feedback if you know them.


Thanks.
Peter.
 

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Pete, if you go to the Club website, and pay 100€/£ to join ... you should be able to contact Mick Popka.

Sorry, but I am of a bit of a recluse ... not much contact with people recently, you are the “unfortunate” individual that happens to appreciate good technology ... regardless of where or when it was created ... :)

As for gearbox durability ... one should consider the original engine torque limits and knock them down (-20%) for normal fatigue acculation. If there appears to be abuse, one should look at NDT to get a good knockdown factor .... otherwise consider a DD direct drive wheel motor ... China is delivering 10-12 kW Hub motors ... 4WD TA. :)

If you decide to go with the latter .. pls stay in touch as I require a 4WD control system for my current design ...a 6x6 Drive is also in the near term ...
 

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Discussion Starter #16
Thanks Rowan. I joined TOC a while back. I’ll try and connect with Mike there.

Regarding wheel hub motors. I’m reluctant to swap out the wheel/drum combos I currently have. I want that portion to look factory. I wonder though if I can mount two of them inboard and drive the existing driveshafts with them.


Do you have a link to the Chinese units you were referring to?
 

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Hi Pete, I have also been lurking for a while, and am working on a Light 15 11BL electric conversion. My car has some way to go before I can start on the drive train, but I've been thinking about it for a while.
I have been considering using a Hilux front diff in place of the gearbox, with the motor mounted behind it (should be just enough space). With a 5.7:1 after market gear set I think it might work.
 

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Pete ... this is the new QS 12-14kW DD

http://www.cnqsmotor.com/en/article...Cooled Electric Motorcycle Hub Motor/538.html

My interest is in justifying the listed mass (43-53kg) it should not require full steel Rotor Cases or Stator ... and more importantly one could replicate the Drum Brake geometry ... in GF/EP (FR4) given the active material for ~15-20kW/motor

If you wish to have inboard motor(s). A shafted rotor version would be required ... opposite of what interests me ... :). QS has several on offer.

I will sketch a Low Mass Motor-in-Drum concept tonight .... posting tomorrow or Wednesday. I am currently attempting to “stuff” 250kW into a 20x10 Bead Lock Design ...

Robert
 

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Discussion Starter #19
Hi Pete, I have also been lurking for a while, and am working on a Light 15 11BL electric conversion. My car has some way to go before I can start on the drive train, but I've been thinking about it for a while.
I have been considering using a Hilux front diff in place of the gearbox, with the motor mounted behind it (should be just enough space). With a 5.7:1 after market gear set I think it might work.
"My car has some way to go before I can start on the drive train".... Hah. I'm assuming that's code for "I have a lot of rust to repair"?

Light 15 and Hilux nomenclature. Are you based in NZ/Aus?

Pete
 

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Discussion Starter #20
Pete ... this is the new QS 12-14kW DD

http://www.cnqsmotor.com/en/article...Cooled Electric Motorcycle Hub Motor/538.html

My interest is in justifying the listed mass (43-53kg) it should not require full steel Rotor Cases or Stator ... and more importantly one could replicate the Drum Brake geometry ... in GF/EP (FR4) given the active material for ~15-20kW/motor

If you wish to have inboard motor(s). A shafted rotor version would be required ... opposite of what interests me ... :). QS has several on offer.

I will sketch a Low Mass Motor-in-Drum concept tonight .... posting tomorrow or Wednesday. I am currently attempting to “stuff” 250kW into a 20x10 Bead Lock Design ...

Robert
Thanks Rowan,
I think I'm going to stick with OEM/salvage parts, where possible. I don't know enough about the in-wheel type to risk that kind of money.
 
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