[tylerwatts]

Hello Tom
This sounds like an exciting build. Don you have any pictures of your car and parts please? I follow with interest.
Cheers

 

[tylerwatts]

That looks like a great setup and powerful with that reduction direct to the rear diff. In such a light donor you could possibly run it without the reduction. Any idea how much torque it produces continuously?
And how much the battery will weigh roughly?
You'll be much better off packaging without the reduction and tucking the motor right into the transmission tunnel.

Apologies if I'm raining on your parade or teaching you to suck eggs etc etc.

 

[tylerwatts]

Here's a picture from the web. Helps see where bits could go.

 

[tylerwatts]

And a view of what's to come. Not the biggest space but with that motor in the tunnel it should be ok. I wonder how much space is available in the fuel tank area to locate chargers or other electronisa. You might struggle with the size of the controller housing but no point speculating yet.

 

[tylerwatts]

Well assuming peak power is at 7000 for guestimates sake, nm = 9.5488 x 90kw x 1000 / 7000rpm = 120nm so x 5.25 = 640nm at the wheels and with stock tyre size is alot! Likely more than the tyres will hold so plenty acceleration.

 

[tylerwatts]

That sounds reasonable.

I was thinking the fuel tank space must be hidden and good for locating larger items, similar to an mx5. It would be good to put the controller up there to give Mac space for battery and keep good weight distribution. And the fuel tank location is a good place to be able to trim/modify the structure to make space for the controller say. It is not too highly stressed as the subframe and chassis structure wrap round there. Well notionally looking at it. I didn't design the car so take my comments with a pinch of salt until you've stripped the car down properly.

I've seen alot of conversions where builders put some battery in the fuel tank area which is ok but it's a compromise with the longer power cables. If you can split the capacity but keep the same voltage in 2 separate packs that would be ideal and it sounds like that might be possible with your setup.

I look forward to any updates you have, don't let me rush you though. Anyway I need to get off my rear and building my conversion.

Cheers

 

[tylerwatts]

Wow those are nice blocks. Shame to break them up.

Regarding batteries, I'd recommend splitting in parallel with same amperage and voltage. So you wire both halves in parallel directly to the inverter or preferably through a junction box with separate pack fuses and even contactors. So you could run off 1 pack at a time in an emergency etc, or if one pack fuse blows you can run off the second etc.

I agree also if it is similar challenge that you split the pack and keep the inverter with the motor rather than move the inverter further away.

Regarding UK law, there are new rules I've not checked but the rule has always been any major changes to structure of the vehicle requires an IVA test same as building a vehicle from scratch. What constitutes major changes is subject to the investigator's opinion but you'll need a basic VOSA inspection to verify the conversion to electric so speak to the centre about any mod to the chassis ref mounting the motor in the tunnel and you should know what's achievable and how far to go. An MOT is always required first but that is easier with an EV.

Regarding mounting the motor in the tunnel and space, if you build a frame into the floor pan with strong box/tube section and load the motor from above your structure should be fine if my stronger. I'd tie it to the side rails of the chassis for added torsional stiffness. And mount the motor slightly offset to passenger side to have good driver leg room as a passenger only needs somewhere to rest their feet.

Any pics of the underside of the chassis would help also, perhaps with a tape measure in view for scale and reference and we can brainstorm a robust design for locating the motor. That is the biggest blocker to begin with because of six and shape in the small car.

 

[tylerwatts]

Tom
I agree with the guys. Given your chemistry all I'd worry about is heating for winter and I'd suggest having air cooling like fans for hot weather. But save that for a future possibility. Ie design your battery boxes so you have space for airflow and fitting a fan but have some insulation in the walls. I'd suggest using angle iron or small 18mm square tube to frame the box and aluminium skin outside. And possibly thin rubber mat to insulate the bricks from vibration. And possibly clamp the bricks top to bottom in the box to keep them together and stable.

 

[tylerwatts]

You'll have loads of torque for sure!

 

[tylerwatts]

Looking very good. You'll need a carbide cutter to drill that sprocket and a very large pillar drill or ideally a mill. Should be a simple job for a tool maker however so try locally for someone to machine it for you. Not worth annealing it then hardening and too thick to anneal locally... Can't risk softening the splines!

 

[tylerwatts]

Looking forward to those pics of progress Tom! Well done getting her moving too.

Cheers
Tyler