2025 Update

 

After a few years and roughly 25 thousand kms of almost daily driving this car I think its time to go over the changes and challenges of this conversion since the last post, and why I've stopped driving it recently.

 

1. Motor coupler:

Initially I had the coupler floating in the bell housing, connected only to the motor spline and gearbox input shaft.

This coupler worked well for anything under 3k rpm, then it started to rattle and shake the whole car!
It almost felt like a rattly 4 cylinder engine was under the bonnet.

This noise was caused by two issues.

The first being the motor and gearbox were nearly 2mm out of alignment... ouch, not good.

The second was the gearbox input shaft, which needed to be supported, rather than floating, as the coupler I used allows for some misalignment.

To fix these issues I had to remake the motor adapter plate, since you cant just move threaded holes 2mm, and added in support for the input shaft with a bearing.

 

 

3. Heater

 I got the MiEVs heater system mounted under the back seats where the fuel tank used to be, with the HV cables running into the boot through a grommet in the spare wheel well.
After running the coolant hoses up the gearbox tunnel to the front I connected the hoses into the beamers factory heater core. 

On start up the heater draws about 20A from the battery, for about a minute or so, until the coolant is up to temperature, then it maintains that temperature automatically (about 65°C)

Even though that temperature is cooler than an engine would run, it's more than enough to heat the cabin quickly.

I haven't yet sorted the CAN information to run the heater system standalone, its currently running attached to the MiEVs heater controls hidden in the glovebox.
Hooked up with the button above the gear stick to supply the controls with 12v, which turns the heater on.
  

4. Airbag light reset

Now this was an annoying problem. While installing some soundproofing on the floor of the car I unknowingly triggered the airbag light by turning the ignition on while the passenger seat was removed, which I now know has a occupancy sensor in it, and is tied into the SRS system.

Normally this wouldn't be a big deal, just get a scan tool, plug it into the diagnostic port under the bonnet, and hit clear codes...

But that port has never existed under my ownership, the previous owner must have cut it out thinking it was useless, which it is, with no engine. Except when you need to clear the airbag light. Sheeeit.

I read countless forums and guides, none of which helped me at all because they all either mention the port I no longer had or an OBD connector which was on cars sold in the US at the time.
Some mentioned a pin you short to ground on the airbag module itself. Nope, not the answer.

After trawling through BMW wiring diagrams I figured out the two communication, pins 15 (RxD), and 20 (TxD) that ran to the diagnostic port, also run to the dashboard.

On connector X16 (the white one connected to the dash) I connected the scanner to pins 11 (RxD), 12 (TxD), and 22 (+12v).

Connector X17 (the blue one connected to the dash) has ground on pin 21.
I also grounded pin 15 on this connector for a few seconds to reset the service interval.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5. 12v battery:

One morning, this horrible smell came from inside the car as I opened the door.
At first I thought something had died under my seat! It turned out to be the 12v battery which the DC-DC had cooked overnight while the car was charging.

The battery had spewed its sulfur smelling battery acid all over the boot and spare wheel well...
Not good... I can still occasionally get a whiff of it when I get in the car over 6 months later!

I think this was because the car had been sitting idle for months before this, and the 12v battery had gone flat and been recharged multiple times.

I've since got a new battery for the car and a trickle charger for when projects sit around to avoid flat batteries.

        

 

 

 

 

 

 

 

 

 6. Aero "Mods" and Range:

To help improve the drag of the car I've put a few big piece of clear acrylic behind the kidney grills, and  behind the bumper, making sure to leave a little gap under the number plate for air flow.
Plus, being clear acrylic, you can still see the radiator behind the grill, so it doesn't look too out of place.

Range wise I can get upto 120kms with flat motorway driving, which weirdly decreases the more city driving I do. Probably because its a heavy, but relatively low and aerodynamic car.
Generally I get about 90-100kms of "usable" range before I start to worry about finding a charger.

This picture is just after some flooding the car was in, it shows the acrylic, and how high the floating bark got!

7.Under the Bonnet:

Added a fiberglass cover to go over all the spicy relays and bus bars, I couldn't put a flat sheet over everything as it would interfere with the bonnet closing.

Also managed to score some Bilstein shocks, and a strut bar to add some rigidity in the front end.

8. Interior/Dash setup:

All the gauges except the speedo are controlled by Arduino's snooping the MiEVs can bus, Fuel, RPM, Temp and MPG.
The two buttons above the gear stick turn the heater on/off, and motor regen on/off. 

9. More power and range?

Now this, is ultimately why I have stopped driving the car recently.

Power was just not enough for me, even with gears, its borderline dangerous when you cant accelerate quickly.

I also got a new job where i need to travel 100+ kms a day, Which was just a little too far for comfortable daily use.

Sometime in the future I'm planning to swap in a different, more powerful motor/inverter combo, and new Chinese cells for better range.
For that I need more money and time, Not something I'm expecting to get anytime soon.

 

 

10. New Daily

So while this project is on hold, I've bought a new daily. A Leaf!

Sound deadened, 160kW inverter, 40kWh battery, Lightweight wheels and lowered on coilovers.
Definitely a fun drive with about 170-200kms range.