Thread: Goingbush's Electric Vehicle project

That's true, but wouldn't the same thing apply to a petrol motor? Wouldn't running it slowly use less petrol than running it fast?
Even in low range, the motor still sometimes works fairly hard, regardless of whether it is electric or internal combustion.

There must be someone with experience of an electric powered vehicle who can tell us what happens and why.

These people would know:

World Solar Challenge 2017

Electric motors work significantly differently to Internal Combustion engines. So much so that no comparison can be made on the power figures, the range can easily be doubled or tripled by going slowly , in Low range there is almost zero load on the motor = almost unlimited range, if thats how it translates in the real world we will see. I read a Tesla Model S recently did 1000km on a single charge by driving at 40kmh

Tesla driver breaks 1,000km-single charge long distance EV record - SlashGear

I can't see how low range would help, the main gears would be spinning faster and creating drag. Teslas etc. don't have any gears. You would have to read a full set of efficiency vs revs vs load curves to find a sweet spot that overcame the extra drag.

Originally Posted by bee utey

I can't see how low range would help, the main gears would be spinning faster and creating drag. Teslas etc. don't have any gears. You would have to read a full set of efficiency vs revs vs load curves to find a sweet spot that overcame the extra drag.

With maximum torque at close to zero RPM , I don't think gear drag will be of any consequence. thats what I see when looking at the graph, but I'm no mathematician. We will soon find out. I just have the Iveco in the shed for more brake work and I'll be getting stuck into the Landy in about a week.

Below is a graph of my motor at my chosen system voltage (144v) you can see that it hardly uses any power at low speed, compared with at 100kmh / 3700 with my 6.50-16 tyres .

That graph is interesting, but I don't know if it includes a variable that I think is important. Is that created with a constant load?

I know that some electrically powered devices benefit greatly from backing off the throttle even just a little bit.

The chart below is for a Torqeedo outboard and shows that if you are prepared to go at about 40% of the speed, the range is over seven times as far and the running time is eighteen times as long. However, part of the benefit comes from the fact that the power required with a displacement hull is a cubic function of the speed. In other words, to go twice as fast, you need eight times as much power.

	Speed in knots (km/h)*	Range in sm (km)*	Running time in hours:
Slow	2.0 (3.7)	20.0 (37.0)	10:30
Half throttle	3.0 (5.5)	10.5 (19.4)	03:30
Full throttle	5.0 (9.2)	2.8 (5.2)	00:35

I can understand how a Tesla could increase its range dramatically by slowing down because it would have only a tiny bit of resistance at low speed. So as well as the benefit of lower revs that the graph shows, the motor would need to produce only a tiny amount of power to overcome the drag.

My impression is that low range work includes trickling along with just a touch of throttle but also includes times when the motor has to produce a reasonable amount of power to climb hills or to push through sand or mud, or to clamber over rocks.

So while I accept that electric motors produce maximum torque pretty much at any revs, I don't think a 4WD used for off-roading would benefit as much from slowing down as a Tesla on a smooth road.

However, I might be wrong.

Hopefully I won't need to wait too long for you to finish your project and either confirm or refute my theory.

Originally Posted by Lotz-A-Landies

I could be wrong, but to me the bolt pattern on the adapter plate replicates the bolt pattern on the engine block. This would mean that you have to use both the flywheel housing, the gearbox bell housing and the flywheel.

The engine side of the flywheel is recessed to fit the crankshaft flange so you may not have a problem at all. I guess time will tell.

It's a pity you're not up here in Sydney as we have a number of spare housings and flywheels that we could do test fits before you need to remove your old engine.

Ive pulled the engine out and see I do have an issue , The face of the Flywheel adaptor is about 15mm too far back.

As I see it here are my options
1/ I need to make a 15mm spacer to sandwich between motor and adaptor plate
2/ Remove a combination of 15mm from motor shaft and Flywheel adaptor .
3/ modify clutch release - a combination of shortening pivot point to move throw out fork reward a few mm and/or make a new thrust bearing holder / get a thinner bearing.

4/ a combination of 2 &3 above .

I wont really even need a functional clutch , I could just install as without throw out mechanism .

I can 'skim' 9mm from the back of the 21.5mm EV flywheel adaptor to bring it to the same thickness as the flywheel flange of the crankshaft .

now I only have to find 6mm , rather than 'trimming' the end of the motor shaft I should be able to get a thinner thrust bearing or mod the bearing holder .