Thread: Electric Defender on Fifth Gear

100km between charges
that would suit me for a town car just fine, would only charge it once a week or so.

If it didnt cost 6 kazillion deniros I would buy one in a heartbeat!!!!
But it would have to be a soft top 90

I have a dream on the longgggg list of jobs to one day "steal" a SWB from 'uncle dick' who has a fair old collection on his property. Gut it of its engine and plonk in a juicy 3ph motor... battery bank in the tray under a false floor and very simple control systems... Just for a town car! Just because it would so nice doing a wharfie in silence with everyone thinking the old landy was dead and just rolling along the street!

Bring it on I say - oh and I spose if we all start driving electric we might need to build a handful of thorium reactors to juice them

S

Originally Posted by MBZ460

Really? I thought have an independently controlled motor at each wheel would allow for a awesome traction control system, not based on wheel braking but by power delivery. Also potentially better clearance since no cross axle.

Imagine a rutted hill climb chewed up by bogans in wannabe comp buggies, your Landy keeps lifting wheels as it runs out of articulation. The climb is steep and load is heavy, it requires 300nM of torque applied to the ground to maintain progress.
An engine in a Defender generating say 400nM, in our perfect world, transmits that 400nM to the transfer case. Torque naturally goes to the easiest release. If the centre diff is open, the torque goes to the wheel with least resistance, such as a wheel in the air. Lift a wheel, stop. Lock the centre diff and the 400nM is available to both front and rear all the time, lift one wheel, 300nM still gets to the ground. Lift wheels at opposite ends, all 400nM is dissipated into wheel spin.
Add cross axle diff locks, and all four wheels have all 400nM available to maintain traction, 400nM is greater than the 300nM required, so driver reaches the top with a smile and wave.
Now go electric, we still have a total of 400nM available, but that is spread over four independent motors, 100nM per corner. Lift one wheel, well well we're on the verge of failing to proceed, 300nM gets to the ground but we need every last nM now. Lift two wheels, uh oh we've only got 200nM when we need 300nM. Failed to proceed.
Without a mechanical link between hubs, electric motors will need (near enough) to be as powerful as the engine they replace.

Even having two motors, axle mounted, will only be as good as a D2 without centre diff lock but with traction control, ie, mediocre.

Now if battery energy density was far far greater it'd be quite reasonable to have each traction motor to produce that 400nM, but that won't be likely for a while yet. And then you'd have issues with all four breaking traction easily and sitting there spinning...traction control doesn't register ground speed only wheel speed!

So stick your big electric motor on the transfer case and distribute the power mechanically.

You could go either way,JLR have a petrol engine providing power plus two traction motors,one front one rear,you could have one each corner,at 25kgs each and providing 150kw each they could all work indedendant of one another and give 150kw per wheel,the only limiting factor would be tyre grip,no diff's/axles,gearbox,TC,clutch etc etc.If I had the money and time I would do what roverrescue posted and build one. Pat

There was an American show I saw on Foxtel about a year ago where they were testing electric cars against petrol.
On one episode they had a guy who converted his series landrover to electric so they put this up against a V8 Disco 2 (I think).
They went through a series of head to head tests which in typical yank fashion didn't prove anything, for example one was against wheel travel, you know where you drive one wheel up a ramp to see how far you get before loosing traction. Yes that tells you alot about petrol Vs electric.
The electric series did go quite well up a steep climb, I think in the end they gave the win to the V8 Disco.

Originally Posted by isuzutoo-eh

...Lift two wheels, uh oh we've only got 200nM when we need 300nM. Failed to proceed.
Without a mechanical link between hubs, electric motors will need (near enough) to be as powerful as the engine they replace.

Even having two motors, axle mounted, will only be as good as a D2 without centre diff lock but with traction control, ie, mediocre.

Now if battery energy density was far far greater it'd be quite reasonable to have each traction motor to produce that 400nM, but that won't be likely for a while yet. And then you'd have issues with all four breaking traction easily and sitting there spinning...traction control doesn't register ground speed only wheel speed!

So stick your big electric motor on the transfer case and distribute the power mechanically.

But surely there is still the advantage that whatever torque you do have is available instantly. So with say one wheel up in the air, you still have an instant 300Nm available.

Most high speed trains use the motor on every wheel principle.

Most high speed trains don't lift wheels off the rail either, so all motors are providing effort all the time and near enough equally.
Aren't they axle hung traction motors, not wheel hung? All the Aussie electric or diesel electrics use axle hung traction motors. And despite having a mere couple of centimetres wheel articulation, they keep their wheels on the rails pretty consistently. No comparison to an off road vehicle.

Yes the way electric motors produce torque is very different to internal combustion, so you get it from zero rpm to everything, a great advantage. But each independent electric motor has to be powerful/torquey enough to do the full job of its contemporary internal combustion engine if the 4WD E-Landy is meant to be as capable as a triple diff locked IC Landy.

The D3/D4 etc wouldn't have the option of a rear diff lock if independently powered wheels were more capable.

Hmmm with wheel mount electric motors, could almost turn a 90 into a skid steer! Better than fiddle brakes!

Mark, you're losing me slightly with your description of torque distribution. I thought that if the centre diff lock was engaged and in the case of a 300TDi you're getting 300Nm (I know its got nothing to do with the engine nomenclature) then you're basically getting 150Nm to the front diff and the same to the rear diff. Then if you lift any wheel anywhere you've lost 150Nm and are relying on the remaining 150Nm with traction to get you out of a whole.
I've always thought a very small diesel motor with alternators providing constant power to 4 independent electric motors at each wheel would be a solution. No need for big battery storage, the diesel is only idling most of the time so driving range is increased dramatically and electric motors have fantastic torque so with four of them (obviously there is a need for some dreaded computer and electronic control) you shouldn't get stuck. I just looked up and found the first search result as a 27kg continuous 400Nm torque (max 800Nm) elect motor. Problem may be providing 75kW of power to each motor. Doesn't sound that hard to me.

Gerald, if the diff is locked, it can't be different from one end to the other. Speed can't vary end to end either.
The physics bumph: Energy is neither created nor destroyed, just transformed. Torque is force times the distance (aka length of the lever/stroke of the engine etc). Force is effectively the energy applied against that lever.

Imagine you hold vertically a lump of 2x4 near the middle and try and spin it with the strength of the very scientific '1 clockwise torque'. Your mate Peter is holding the top trying to stop you turning it. The other end is free. He has to apply equal and opposite force, 1 anticlockwise torque to what you apply to stop it turning.

Then he changes end. He still has to apply 1 anticlockwise torque to the bottom to stop you spinning it, because you are still applying 1 clockwise torque and the top is doing nothing.

Third time, he grabs with one hand on each end-the sum of the force he puts in at each end still has to equal 1 anticlockwise torque to stop your 1 clockwise torque to stop it turning, but he can spread it over two ends. The sum of both ends still equals 1 anticlockwise torque. But if his left hand is weak, the sum of his efforts still has to equal 1 anticlockwise torque, so his right hand has to put in more effort. Say he suddenly lets go with one hand, the one still holding on still has to apply a total of 1 anticlockwise torque to prevent you winning.

Just because one end isn't feeling strong (wheels in the air or on slippery mud) the other end doesn't get half hearted or there'd be a whole lot of torque escaping, and as energy is neither created nor destroyed, it'd be transformed into something like noise, heat, or buckling metal...

An ATB/trutrac/quaife geared LSD however does have a torque split, be it 50:50 or 70:30 or what have you, because the ends aren't mechanically locked together as such.
Hope that all makes sense...