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Hello Everyone, I would like to share what I am planning for my project and would like some feedback from you based on your vast knowledge and experince in the subject :)

I am planning to convert a BMW 'e30' 316i touring to EV using the Motor/Inverter from a Nissan Leaf.

The e30: it was choosen as it is a classic that in smaller motors like this is still affordable. It is a strong and well built car with a big community of DIY in internet, so lots of information on how to fix it later. It also offers a good relation of weight vs space to work. I have some options already found and believe this could work just fine.

The 'Nissan Leaf' motor/Inverter: I think it has a good cost and more than enough power for what I need and many options of controler board in the market (I was considering buying one from open inverter here in Germany). I was considering a small unit from Tesla but as it comes integrated to the diff, I would need to cut the spare wheel well to assembly it under the rear floor and I don't know how the TÜV here would see that. If I can make it work work simpler with the leaf, why not?

Battery: I will leave this to the end, when everything is ready I will check what is affordable and Buy. I want to start with a small pack just to homologate and see how reliable and pratical it goes and expand it later.

NO Gearbox: Here is my biggest doubt. I would like to go without tranmission. I would like to link the motor to the diff just modifing the existing shaft. If possible at the fuel tank area, if not at the original transmition spot. The diff would be a 4.4 ratio from the e30 316 AT. The problem is that is much longer than the 8 ratio from the leaf. The e30 is lighter than the leaf and has smaller wheels but would that be enough to make it work? (work for me means: don't destroy itself and 0-100 around 10s).

Does anyone know any project that used similar configuration?

One other open concern that I have is the 'TÜV' approval here in Germany. Is there anyone here that knows more details that could help me. I don't want to start spending money and run the risk of having a non road legal vehicle stuck in my garage later.

Thanks everyone for your attention and looking foward to hear from you soon.
 

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The 'Nissan Leaf' motor/Inverter: I think it has a good cost and more than enough power for what I need and many options of controler board in the market (I was considering buying one from open inverter here in Germany). I was considering a small unit from Tesla but as it comes integrated to the diff, I would need to cut the spare wheel well to assembly it under the rear floor and I don't know how the TÜV here would see that. If I can make it work work simpler with the leaf, why not?
All modern EVs use a motor integrated with a transaxle; the Tesla and Leaf configurations are very similar, following the most common pattern of one motor per axle, a two-stage single-ratio reduction gear set, and an open differential, all mounted transversely. The biggest differences:
  • All Model S/X drive units and the Model 3 front drive unit place the motor behind the axle line, while the Leaf and Model 3 rear drive units place the motor ahead of the axle line.
  • The Leaf motor does not share lubricant or coolant with the transaxle and is readily separated from the transaxle; in contrast, the Tesla (at least Model S/X) motor's end housing also one side housing of the gearbox, and the same oil is pumped through the motor bearings and the gearbox.
  • Tesla inverter housings are attached to the transaxle housing, opposite the motor, while the Leaf inverter is stacked on top of the motor.
So either one could work as a complete drive unit at a rear axle, but the Tesla would be a better fit with the E30's semi-trailing arm rear suspension... and I agree that it is easier to separate a Leaf motor so it is an easier choice is using the motor only, longitudinally mounted and driving a shaft to the original final drive (diff).

NO Gearbox: Here is my biggest doubt. I would like to go without tranmission. I would like to link the motor to the diff just modifing the existing shaft. If possible at the fuel tank area, if not at the original transmition spot. The diff would be a 4.4 ratio from the e30 316 AT. The problem is that is much longer than the 8 ratio from the leaf. The e30 is lighter than the leaf and has smaller wheels but would that be enough to make it work? (work for me means: don't destroy itself and 0-100 around 10s).
Gearing is certainly an issue. Are you sure that the converted E30 would be significantly lighter, even after adding a useful amount of battery?

One solution to this is to add a reduction gearbox on the output of the motor (less than 2:1 ratio is all that is needed), but that's neither trivial nor cheap.

I think a realistic look at the size of the motor versus the available space in either the transmission tunnel or the fuel tank area is called for. The tunnel is unlikely to be as wide as the motor diameter and the fuel tank is nowhere near as tall as the motor diameter.
 

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Discussion Starter #3
Hello Brian, thanks for your feedback.

Tesla would be a better fit with the E30's semi-trailing arm rear suspension... and I agree that it is easier to separate a Leaf motor so it is an easier choice is using the motor only, longitudinally mounted and driving a shaft to the original final drive (diff).
Tesla would fit nicelly once spare wheel well is chopped off or there is not enough space behind axel. Your feed back on motors match to what I had researched which is good start :)

Regarding the weight the Leaf weights 1458kg, the BMW E30 318i touring weights 1220 (including fluids, fuel, exaust and 130kg of powertrain). I am planning a small battery (around 140kg) in the engine bay and the idea of putting the motor and eventually the inverter and the charger in the fuel tank area and with these try to keep the weight balance and don't spoil the great driving of the e30.

You raised a great concern about the motor not fitting in the tunnel nor in the fuel tank area. I don't have the measurements and if it is the case the hole concept I have in mind would not make any sense.

Thanks again!
 

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Regarding the weight the Leaf weights 1458kg, the BMW E30 318i touring weights 1220 (including fluids, fuel, exaust and 130kg of powertrain). I am planning a small battery (around 140kg) in the engine bay and the idea of putting the motor and eventually the inverter and the charger in the fuel tank area and with these try to keep the weight balance and don't spoil the great driving of the e30.
That makes sense. With a full Leaf battery pack (or similar capacity pack from another source), the E30 would weigh at least as much as the Leaf.

I understand the target of car with good handling, and it should be obvious that a small battery would mean a short range. A small battery also means limited power; in the Leaf, motor power was limited to 80 kW until the larger batteries were offered, to avoid killing the batteries. That was 80 kW with 24 or 30 kWh, 110 kW with 40 kWh, 150 kW with 62 kWh... and if you go the other way, an even smaller battery of the same design would allow even less power.
 

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It is a good point that I still don't have very clear. I was also considering having tesla batteries or building the battery myself using 18650 recycled cells, but my first priority right now is to find someone that could give some guidance on the registration process here in Germany.
 

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There are a number of companies in Germany that specialise in electric conversions, and that would be able to help you with parts and/or advice about how to deal with the TÜV.

Try these to begin with:
http://www.lorey-maschinenbau.de/blog/elektroauto/
https://www.fleck-elektroauto.de/

Both Marco Lorey and Heiko Fleck are very knowledgeable and approachable. I spoke to both of them at length when I was planning a Mercedes 190E conversion last year.

You're lucky to be in Germany, where electric conversions are doable and legally possible. I live in Spain and eventually gave up on my project when I realised there was no realistic and affordable way of legalising it. Still regret it though, which is why I keep coming back to this forum ;-)
 

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So, some updates in my elaboration phase. I am getting more and more inclined to end up using a tesla small drive unit behind rear axle similar to the example listed by @ecs (Thanks by the way), just not with the large unit as I am not planning to load so many batteries to feed all its potential anyway, so stay with lighter option. The price of a unit like that is very similar to a leaf unit and it performs better, and would eliminate a potential weak link, the e30 diff.
My problem now is to find a decent, rost free e30 for a reasonable price...
With the tesla unit, the vehicle weight is not that critical anymore, and with all the difficulties for finding a good e30, I am already considering using the e36, the problem is that the sway bar would be on the way of the motor.
 

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Hey nice to see another Tesla drive unit project!

@GeneralElectric ; Yes Spain is a lengthy and costly project. If I was you I would go the export/import route. That means that you need to modify a German vehicle and when it's homologated / correctly registered you reimport it to Spain. The legal basis within the EU says that every vehicle which has a license plate should be admitted at every member state. You should give the INTA a call or IDIADA. As long as an American car can be imported yours can be too. As long as the registration is correct.
From the days I was in the kitcar (locost seven scene) in Spain the emissions where an issue, with electric that's tackled.
www.boon.cc these guys can help you I guess.

@E30 EV ; Hi neighbor! :) Albeit Germany is really big. First step about getting the adoption signed off is informing about the rulez by the TUV. Leaving the Tesla inverter stock will help you because for us two I expect the rulez for EMC will be the same.
We nee to comply with ECE R10 that means that most easily we get through using all stock devices and already certified devices.
At least it's the cheapest option to avoid a measurement / check of the complete vehicle.
 

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Hi. The effort of making a conversion in Germany is strongly dependant on the TÜV-engineer's attitude. There is a certain scope how he (or she) can handle the matter. EMC is not absolutely necessary on older vehicles, but the engineer may insist. This is the moment where You should go to another TÜV-place.

E30EV: You invest a lot of time and money into such a project. You should start with th car that you really want to convert and to drive later. If this is the E30, don't stop searching for exactly that. There is one, somewhere.
Good success!
Masrkus
 

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Sorry, I don't.
I have done a classic Mini with a Th!nk-drivetrain, and I am repeating this currently, to give my children their own Mini (and hopefully getting my car back).
Markus
 

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So, some updates in my elaboration phase. I am getting more and more inclined to end up using a tesla small drive unit behind rear axle similar to the example listed by @ecs (Thanks by the way), just not with the large unit as I am not planning to load so many batteries to feed all its potential anyway, so stay with lighter option. The price of a unit like that is very similar to a leaf unit and it performs better, and would eliminate a potential weak link, the e30 diff.
My problem now is to find a decent, rost free e30 for a reasonable price...
With the tesla unit, the vehicle weight is not that critical anymore, and with all the difficulties for finding a good e30, I am already considering using the e36, the problem is that the sway bar would be on the way of the motor.
Good move I must say. I also learnt from your submissions to carry out similar try outs. I also found this useful. Diesel Generators for Sale - UK | Prime Power Solution
 

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I already thought that, didn't even bother to check the link but thought lets ask the dump/smart question :)
 
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