Z3 EV Conversion

[Andybpowell]

So I know Tom has been posting his EV conversion up here but since this type of project is likely to become more common I thought I'd give you my take on it
I've been a petrol head forever and this is my first EV conversion but in the past I've done lots of engine conversions and general modification including
Rover V8 into Ford Capri, Turbo 2l Capri, Fiat X19 turbo conversion, Individual throttle bodies, rearmount turbo and Air ride on my Nissan 350Z any way you get the idea
so this is my car a 99 2.0l manual in topaz blue

The conversion will use the Nissan leaf em57 motor and inverter with an open inverter control board and if I can squeeze both in 2 BMW 530e battery packs Battery management will be a modified version of SimpBms and the charger is from a Volvo (not sure which one) since this started out as a conversion of a Mini Cooper S much of the development work around the electronics has already been done and is mostly unaffected by the change of donor vehicle so far I have concentrated on the bodywork as the side rocker panels (cosmetic outer sill) were a bit worse for wear though the structural sills underneath were excellent with very minor rust these have been replaced

I had to take this back to bare metal as it had been poorly filled so was easier to start again.

and there it is all ready for the conversion to begin

 

[Lee]

Watching with interest! keep the updates coming

 

[Andybpowell]

I'd never removed a Z3 engine before so it was a bit of trial and error

overall it wasn't too troublesome pretty straight forward

 

[Stevo7682]

Looking forward to reading up on your build.
The thing that I am looking forward to gaining more information on is how many miles per charge can be achieved with the various types of installation.
Stephen.

 

[Andybpowell]

This is the complete leaf drive unit as it arrived charger/dc to dc converter on top under that the inverter and under that the motor it also came with the reduction gearbox

this is how much of it I will be using the inverter, motor and half of the reduction gearbox

to make the coupling I removed the centre of the BMW clutch plate cut the Nissan leaf output shaft down to size made up an alignment tool to ensure its all in line and welded the two together

 

[t-tony]

Where are you located please Andy? Very interesting threads these and very on point these days.

Tony.

 

[Bazza]

Wow very interesting keep us up dated please

 

[PHILIP BAXTER]

This is going to be a great thread. Keep up the good work.

 

[Andybpowell]

Where are you located please Andy? Very interesting threads these and very on point these days.

Tony.

Southend on Sea, Essex

 

[Andybpowell]

Having offered up the motor with part of the reduction gearbox/diff casing still attached to the gearbox as I suspected clearance around the steering was going to be an issue

so I had to introduce the casing to my milling machine

to strengthen it back up and stop the casing filling up with crap off the road I then welded the cut end back up

No more clearance issues

I'll post some more a bit later if I find time in my busy schedule

 

[Andybpowell]

Just a quick comment, this is what I am and will be working under to complete this project excellent for the money and take up minimum space when packed away though not light

View: https://youtu.be/i8M--HBSkcg

 

[Andybpowell]

So for the adapter plate to mate the BMW bellhousing to the Nissan leaf reduction gearbox/diff housing I am using a 400mm x 400mm 12mm thick 5083 ally plate a decent hardness and good corrosion resistance
the template I have made from 6mm mdf board. First of all I made up some transfer punches on the lathe to the exact size of the holes in the bellhousing to ensure that I got the exact locations
then painted the face of the bellhousing to give me a nice outline and clamped the board to the bellhousing
I then used the custom made punches to mark the board, the gearbox input shaft location was calculated from some of these bolt holes.


I then mapped the locations of the locations of the leaf reduction gearbox/diff housing bolt holes and output shaft using a camera attached to my CNC mill

I then marked the gearbox vertical on the template and clamped it to my mill aligned the gearbox and motor shaft and vertical orientation and drilled the holes that I mapped earlier and there you have it a hopefully accurate template

 

[Bazza]

CNC mills and Lathes oh the memory love this thread

 

[Zag2]

Brilliant stuff, these types of conversions are getting so popular. All it needs is someone to engineer the bits and others will benefit in the future.

I can see the potential for a whole new industry making the adapter plates and bits available to just bolt on to popular classic cars.

 

[Andybpowell]

CNC mills and Lathes oh the memory love this thread

I try to please.

 

[Andybpowell]

Brilliant stuff, these types of conversions are getting so popular. All it needs is someone to engineer the bits and others will benefit in the future.

I can see the potential for a whole new industry making the adapter plates and bits available to just bolt on to popular classic cars.

There already is a market for it but the prices they charge are obscene

 

[Andybpowell]

As I'm now stuck waiting for an expensive chunk of ally for the adapter plate to arrive

 

[Andybpowell]

It's absolutely bucketing it down outside so I might as well continue showing you some more of the components of my build
these are the batteries which are from a BMW 530e it uses the same packs as the 330e tom used in his build but contains 6 instead of 5 modules which gives you approx another 60 Volts

and this is what it looks like inside

and this is a picture of all of the bits I needed from it, the battery modules with their slave bms units and what BMW calls a safety box which has the
pre-charge components and the contactors and main fuse

this is inside the BMW safety box

the control board bottom left is now gone as I will be controlling it with my own external controller one of five boards I have made for this project

the board far right is the one which will control the two BMW safety boxes this board provides three PWM outputs to each of the safety boxes
and provides logic to control the contactors and pre-charge circuits
the top two boards are the battery management boards which will control the bms slave units attached to each of the battery modules these communicate with the bms slaves and my own control board (bottom left) via canbus the board bottom left then communicates with the charger control board, charger and the inverter

the board above is the one which controls the wall charger I made the boards myself except for the BMS slave control board which I modified from a design by Tom De Bree and is running my own skeleton version of his software

View: https://youtu.be/wpLlyalMevA


Ok to clear a few things up
A contactor is basically a relay designed to switch much higher voltages/current than a conventional relay sometimes the contacts themselves are sealed in a vacuum or an inert gas to control arcing
A pre-charge relay and resistor are there to protect the contactors and other components that may be damaged by the inrush of current you would get if you just connected your battery pack to your controller containing uncharged capacitors. to avoid this you usually connect your battery to the controller through a resistor via a pre-charge relay to charge the capacitors gradually before switching over to the main contactor this can be controlled by a timer or by monitoring capacitor voltage
In PWM the power is switched on and off at high speed using this method we can use digital electronics to give us what seems to be an analogue output for example if the on voltage is 10 volts and the off voltage is 0 volts and you switch it on and off so that it is on 50% and off 50% of the time the average voltage will be 5volts if it’s on 25% of the time and off 75% you would see an average of 2.5volts
**these are simplified explanations sufficient for the purposes of this post

 

[Bazza]

So much knowledge, I’m sure I would end up with a migraine, very impressed to say the least

 

[Andybpowell]

So much knowledge, I’m sure I would end up with a migraine, very impressed to say the least

AHH that could explain my headache