motor direct to t'case or into gearbox?

[akelly]

Hi folks - planning to go EV with my series 1 rebuild and looking at the various configuration options. What's the story with putting the motor direct to the transfer case, rather than through a gearbox/clutch? To my mind this seems like a good option for removing friction and inefficiencies but the only conversions I can really find online are through the gearbox. Anyone have useful thoughts about this, or point me to some info on it?

Cheers,

Adam

[cjc_td5]

Perfectly feasible, but I think that main risk is stalling out the motor at low speeds. Electric motors want to run fast. You may find yourself using low range more than you realise?

[akelly]

oh yeah, I should have said through a reduction drive not literally direct into the t'case. Maybe 2:1 or something of that nature.

[edit] I've been looking at this product as an example of the reduction box: EV Transmission Reduction Gearbox for Electric Vehicle Motor

[cripesamighty]

If you haven't checked this out yet already, there is some great info on Goingbush's EV project and should point you in the right direction.

Goingbush's Electric Vehicle project

[akelly]

he went through the gearbox, I'm talking about removing the gearbox.

[goingbush]

90% of the time I drive mine around town in top gear, which is the same as going direct to the transfer case . My motor only has 150Nm
Its not enough to get over a kerb if your parked up against one , even in Low range it wont . So if your in a hole you wont be able to get out of it

a wise man told me you need approx 6000nm at axle to climb a vertical obstacle , which could be a log , rock or high kerb , or extracting yourself from a hole

150Nm x 1.148 transfer case high x 4.7 diff = 809nm at axle . high range , (top)
150Nm x 2.35 transfer case low x 4.7 diff = 1656nm at axle . low range , (top)

add in a gearbox
150Nm x 3.6 first gear x 2.35 transfer case high x 4.7 diff = 5964 nm at axle . low range first gear ,

you need to do some maths , You want to have approx 6000nm at axle in low range , but have the motor sit in its happy RPM range at 100kmh , no more than 6000RPM

if you chose a 250Nm Nissan Leaf Motor with a 2:1 reduction box before the transfer case you will be close.

Plenty of Series Landrovers have been converted direct to gear box but doubt they are useful off road .

I made this video for Steve Jackson who is converting one , so he could decide yes or no to a gearbox . He is installing a DC Series Wound motor with more torque than my AC51 , So to make sense of the video when I'm in Top gear its my actual performance as would be without a gearbox, When I'm in 3rd gear its Simulating the DC motor as it would be in top gear (equivalent torque)


This video , cant get up the obstacle in Low Second , this is Low first , enough torque to hold it up there on throttle


these two show that power consumption isnt greatly affected by gear ratio




given enough power you can control your torque with throttle so this one isnt really as relevant as it seems


if your on facebook you might find something useful here
Electric LandRover and 4x4 EV Conversions

[goingbush]

A bloke in the AEVA is converting a Pajero to Electric, he is using two chinese motors one into each diff.
He has made himself a pair of torque boxes using 2.45 (or it might be 2.65) helical planetary low range gears from Hilux / Prado transfer cases , they are beautiful things.


With a Leaf motor you could just use a complete Prado transfer case instead of the Series transfer case , The Helical planet low range is whisper quiet and the ratio is great , You could slip it into High range for tootling about . I'd seriously consider that as an option.

you would lose the transmission handbrake though and need to centralise the rear diff

[akelly]

unreal, this is the sort of info I'm chasing thanks!

You're running stock 4.75:1 diffs [editr - yep, re-read and noticed you said 4.7:1] and a stock series 3 transfer case I guess? I don't know much about lightweights

[goingbush]

unreal, this is the sort of info I'm chasing thanks!

You're running stock 4.75:1 diffs [editr - yep, re-read and noticed you said 4.7:1] and a stock series 3 transfer case I guess? I don't know much about lightweights

Lightweights are mechanically identical except for flat 24spline drive flanges (and different half shaft ends )

I have a Standard series 3 gearbox and transfer case.
I put a metric diff in the rear to run an Ashcroft 4.75 with 24sp HD halfshafts and a truetrac centre
Front diff is standard 4.7 with TT centre.

The mismatched diff ratios make it feel much better off road as the front wheels want to spin slightly faster to keep it in a straight line. maybe its just in my mind, dont have any wind up issues.