justaddmud wrote:Surely a motor that can produce 100% torque from 0 rpm would make gears pointless, hitch the motor straight up to the t-box, no need for a clutch as there is only one gear, and as for reverse, just reverse power to the motor
Your idea is very similar to mine! Didn't see your post, I promise I wasn't stealing your idea!
dan_2k_uk wrote:Even with 130ft/lbs of torque imagine pulling away in 5th all the time.
Couple that with the motors reccomended max of 2500rm even if it could pull away like that the top speed would still not be.that great.
It wouldn't be like that, since you can't stall an electric motor, and it has 130lb-ft from 0 to redline. So it'd be more like doing a rolling start at 30mph in 3rd with a turbodiesel that's just coming into it's peak power band. Only you get that acceleration from 0 to wherever the gearing redlines you.
It'll PULL. It won't break any 0-60 records, but it won't be anywhere near as dire as you think. Bear in mind the transmission on a sammy results in about a 35% loss of power, and by ditching the gearbox and t-case, you'd only be loosing power in the diff gearing (probably about 15%) so you'd be getting an extra 20% of power at the wheels for free, plus the associated range increase, lower fuel costs etc. i.e. it should pull like a 155ft-lb ICE engine.
twiss wrote:Anton -
I think you've gone wayyyyy over the top there. I'm not going to be putting a motor on each corner!
I want it to be an electric powered SJ, with the same transmission and axles.
Also, I'm not going to need 200ft/lbs of torque from 2 motors.
Each motor costs almost £1,500 so I will only be getting one, an AC motor requires about 9 car batteries and a DC motor requires about 12 car batteries.
The whole set up I'm looking at about £3000.
But if I can get to work for a fiver a week thats paid for itself in 2 years
Well, I guess it's my fault for writing war and peace - but you missed my point. I wasn't suggesting that you put a motor in each corner - I said I thought about suggesting it until I did the maths and realised it was a *TERRIBLE* idea!
The *real* suggestion was to put ONE motor where the t-case is now, connected directly to the front and rear props. With 31's and 3.73 samurai diffs, you'd have 63mph at 2500rpm, with the torque to get you there quick enough. And if you drop a motor in that's capable of more rpms, you can adjust the top speed/acceleration by dropping different diffs in - V6 vitara diffs, for example, at 4.something:1 or 1.6 vit diffs at 5.something:1.
That way you get rid of the torque losses associated with the gearbox and t-case. I'm not an EV designer or engineer, though - so I'd say you'd better talk to someone who's built one if you do consider my idea, as they're much more likely to know if it's a good idea, or if I'm missing some vital piece of the puzzle.
I would like to oppose your idea of using car batteries though. Bad idea. They're not designed for deep cycling - what you need is fork lift truck batteries. Go talk to a company that maintains forklifts, and get their old used up batteries. They throw them away once they get down to 40% capacity - which is still good enough to use as a "proof of concept" before you throw real money at brand-new deep-cycle batteries, especially if you use the arc-welder trick to bring them back to near 100% for a short while.
