[WIP] BMW E91 + Leaf Motor

Tell us about the project you do with the open inverter
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EdAtki
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[WIP] BMW E91 + Leaf Motor

Post by EdAtki »

Hello everyone, this is my first time posting on the forum :)

An EV conversion is a project I've been wanting to tackle for years now but never managed to get out of the planning phase, however I recently stumbled across a deal too good to turn down. I acquired an 80kW Nissan Leaf motor, inverter and PDM for just £150. Purchasing those first components has really given me the motivation to get started on this for real.

I also have a lead on a 50kWh battery pack from a Peugeot E-208 for a very good price. I believe this is a 108S pack though so I could do with some advice on whether the leaf power train can handle the higher voltage or if I'd have to run fewer modules bringing me down to about 44kWh. I'd ideally like to achieve 100 miles range which I think is feasible, I'm basing that on a 40kWh leaf and hoping that having a bit more battery but being a bit heavier and less efficient will balance out to be make it roughly equivalent. These battery modules each have a built in satellite BMS based on a MAX17823 and I'd build my own master BMS module based on the fine work that's already been done by folks on this forum.

The leaf PDM I may or may not end up using as its quite bulky and the charging is a very slow 3.3kW.

I'd go with a zombieverter to tie things together and be the main brains of the car.

The trickiest part of this whole process has been deciding the car to install it all in. I didn't get the reduction gearbox with my leaf stack so I will have to bolt the motor to the original gearbox of the car so I need something manual and preferably rear wheel drive as I wouldn't be confident the leaf motor would fit on a front wheel drive gearbox. I am currently leaning heavily towards a BMW E91, these are quite commonly being advertised for cheap with failed timing chains or seized engines.

I wouldn't be the first to convert a E91, I know its already been done by someone on this forum, so that's quite reassuring that it can be done and that a lot of the CAN bus trickery has already been figured out.

The E91 already has significant room under the boot floor but even better than that the spare wheel well is a separate bolted in panel that could be replaced, so plenty of room to fit batteries and no need to cut or drill holes in the chassis. Also the engine bay is pretty large and the leaf motor should take up relatively little space so plenty room for components and potentially more batteries up front too.

Later models already have electric power steering which saves me some work.

The 80kW power train might sound underpowered for a car of this size but it actually has similar torque figures to the original engines, so running it through the original manual gearbox I'm hoping for similar performance and if it does prove to not be enough I can always upgrade to the 110kW or 160kW inverters or install the open inverter logic board for ~130kW.

I'll be posting updates as the project progresses.
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Re: [WIP] BMW E91 + Leaf Motor

Post by Bigpie »

100 miles range is easily achievable. My E91 has a 36 kWh pack and I get around 120 miles.
The electric rack fits the older models. I love my E91, but be aware of high insurance costs. There's only Adrian flux that I could find to insure.and it's over a grand. No points, no accidents, 20 years no claims.

I'm in Rotherham if you want to poke around mine
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Re: [WIP] BMW E91 + Leaf Motor

Post by Alibro »

EdAtki wrote: Sat Jul 12, 2025 8:55 pm Hello everyone, this is my first time posting on the forum :)

An EV conversion is a project I've been wanting to tackle for years now but never managed to get out of the planning phase, however I recently stumbled across a deal too good to turn down. I acquired an 80kW Nissan Leaf motor, inverter and PDM for just £150. Purchasing those first components has really given me the motivation to get started on this for real.

I also have a lead on a 50kWh battery pack from a Peugeot E-208 for a very good price. I believe this is a 108S pack though so I could do with some advice on whether the leaf power train can handle the higher voltage or if I'd have to run fewer modules bringing me down to about 44kWh. I'd ideally like to achieve 100 miles range which I think is feasible, I'm basing that on a 40kWh leaf and hoping that having a bit more battery but being a bit heavier and less efficient will balance out to be make it roughly equivalent. These battery modules each have a built in satellite BMS based on a MAX17823 and I'd build my own master BMS module based on the fine work that's already been done by folks on this forum.

The leaf PDM I may or may not end up using as its quite bulky and the charging is a very slow 3.3kW.

I'd go with a zombieverter to tie things together and be the main brains of the car.

The trickiest part of this whole process has been deciding the car to install it all in. I didn't get the reduction gearbox with my leaf stack so I will have to bolt the motor to the original gearbox of the car so I need something manual and preferably rear wheel drive as I wouldn't be confident the leaf motor would fit on a front wheel drive gearbox. I am currently leaning heavily towards a BMW E91, these are quite commonly being advertised for cheap with failed timing chains or seized engines.

I wouldn't be the first to convert a E91, I know its already been done by someone on this forum, so that's quite reassuring that it can be done and that a lot of the CAN bus trickery has already been figured out.

The E91 already has significant room under the boot floor but even better than that the spare wheel well is a separate bolted in panel that could be replaced, so plenty of room to fit batteries and no need to cut or drill holes in the chassis. Also the engine bay is pretty large and the leaf motor should take up relatively little space so plenty room for components and potentially more batteries up front too.

Later models already have electric power steering which saves me some work.

The 80kW power train might sound underpowered for a car of this size but it actually has similar torque figures to the original engines, so running it through the original manual gearbox I'm hoping for similar performance and if it does prove to not be enough I can always upgrade to the 110kW or 160kW inverters or install the open inverter logic board for ~130kW.

I'll be posting updates as the project progresses.
I used a Gen1 Leaf motor and Inverter in my Freelander build and it works great great but for a BMW I would go for a Lexus transmission. The motor and inverter takes up a ton of space under the bonnet which leaves a lot less room for batteries.
As for choosing the car make sure it's a car you like and want to drive. You'll spend a lot of time, money and effort on it so you want to be proud to show it off when it's done.
EdAtki
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Re: [WIP] BMW E91 + Leaf Motor

Post by EdAtki »

Bigpie wrote: Sun Jul 13, 2025 7:11 am I love my E91, but be aware of high insurance costs. There's only Adrian flux that I could find to insure.and it's over a grand. No points, no accidents, 20 years no claims.
I think insurance on any conversion is going to be a pain unfortunately, I would love to hear what insurance has been like for others in the UK, is the E91 is particularly bad for some reason?

Alibro wrote: Sun Jul 13, 2025 7:57 am I used a Gen1 Leaf motor and Inverter in my Freelander build and it works great great but for a BMW I would go for a Lexus transmission. The motor and inverter takes up a ton of space under the bonnet which leaves a lot less room for batteries.
I don't disagree that a lexus transmission arguably makes more sense but I picked up the leaf stack for cheap so that's the route I'm taking, besides I quite like the idea of retaining the manual gearbox.

Alibro wrote: Sun Jul 13, 2025 7:57 am As for choosing the car make sure it's a car you like and want to drive. You'll spend a lot of time, money and effort on it so you want to be proud to show it off when it's done.
Its a car that has never really been on my radar, all BMWs sort of just blur together to me haha, but having gone to see one I am absolutely sold. It's comfortable, it's practical, it's good looking, it has a good aftermarket; it's a car I would love to own.
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Re: [WIP] BMW E91 + Leaf Motor

Post by Bigpie »

BMW are more expensive to insure. My converted 2003 beetle was 400.
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Re: [WIP] BMW E91 + Leaf Motor

Post by Alibro »

Bigpie wrote: Sun Jul 13, 2025 1:04 pm BMW are more expensive to insure. My converted 2003 beetle was 400.
Landrover are even worse. I'm paying over £700
EdAtki
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Re: [WIP] BMW E91 + Leaf Motor

Post by EdAtki »

I've run quotes on a few potential cars, albeit in unmodified form, and the E91 was very reasonable. I'll give adrian flux a call to see if they can quote me with the conversion. Thanks for the heads up
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