[Craig]

Hi,
I'm planning on converting my own EV, but I need a little help
Basically, rather than doing the usual motor replacement, I'll be using in-wheel motors (2 of them), simply because I won't need a gearbox, transmission etc, so less loss, and less weight (in my wallet too ^^), plus I can use the freed space for the batteries, rather than waste trunk space.
So far I've found (the only?) three wheel motors manufacturers...
PML : they make a very powerful motor, and have made their own conversion to showcase it. It's actually a hybrid (with a go-cart engine used as a generator). It's a 4-wheel drive mini, does 0-100kph in 4.5s, has a top speed of 240kph, and over 640bhp. Problem is, the motors haven't entered production yet, so they cost £9k apiece, plus £4k for a 2-wheel controller...Let's say it's a little over budget
TM4 also make "just" one motor, and have no real pictures or applications, so I suppose they haven't entered production either...But the big advantage of these is the mechanical brakes (which are the minimum requirement if I hop to make the car street-legal)
the last one I found is e-traction. Their "TheWheel" looks very promising, and they've already made quite a few EVs (not hybrids) with them, plus they're based in Europe, so that means less shipping fees if I get those

Anywho, does anyone know anything about these (or just wheelmotors in general)?
And what kind of batteries would be best? I won't have an infinite budget, but I still need something efficient . I was thinking of Li-Ion, or maybe even that new ultracapacitor battery that's supposedly going to be 10 times as efficient as lead-acid, at half the cost. It should be out sometime before the end of the year I think (though I can't find much detailed info) EDIT - I can rule out lithium batteries. I just read that they can explode if crashed...I was going to put them under the hood, so it's probably better to go with another type of battery Any suggestions?
btw, I'll probably be converting something rather big (as in Dodge Caravan -big), because I want to be able to transport alot of people (and have space for skis)

Thanks in advance,
Craig

 

[KiwiEV]

I think you'd be a pioneer converter using the hub motors/motor per wheel setup. Good for you.
If you do find any information on these super-capacitors that sound too good to be true let us know. I've heard of them myself and I'd love to get my hands on them if they're as good as they say they are.
Do you have a donor car yet?
Keep us posted!

 

[Craig]

no, not yet, I want to finish planning it first (well at least get more info on the motors - i sent emails three days ago), but I could probably get my parents' old car back from the garage... it's a chrysler voyager with a dead gearbox, and it should still be there, they sold it less than a year ago for about 1000$
But even if they got rid of it, I'm sure I can find another minivan (or even another chrysler voyager... the 2nd generation was so crappy )
In the meantime I'll make a blog to post updates...I'll put the link here when it's done

 

[moldiebrownie]

The only thing I've heard about hubmotors is that Mitsubishi is gonna produce a car that usese 4 of them...what brand..I don't know.
http://crave.cnet.com/8301-1_105-9717035-1.html?&ag=rssad.6182152&ubj=news

This 8 wheeled Japanese EV also uses hubmotors http://en.wikipedia.org/wiki/Eliica

 

[KiwiEV]

Maybe. Someday.
I remember getting excited about the new Mitsi EV's almost 2 years ago. They predicted the EV's will be in production by now. And noooow they're predicting production to start next year. I've heard this before...
By 2010, they'll be just around the corner!

 

[Craig]

Mitsubishi are making their own motors, and it's going to (or rather, it might eventually perhaps) be a production vehicle, so I doubt they'll sell the motors separately.
As for the eliica, I don't really see there being a market for a huge 8-wheel drive car, but who knows? Maybe they'll sell the 200 cars they want to make...

 

[rbgrn]

Why have 8 wheels? That seems inefficient. I'd prefer to see 2 sets of 4 motors coupled together to make an all-wheel drive train using 4 wheels.

 

[moldiebrownie]

Maybe you've already seen this Craig but heres an interesting video I found on Yootube about the 8 wheel Japanese car http://www.youtube.com/watch?v=UltoB9hvLNk

 

[veperformance]

Wheel motor are the ideal setup on a track but in real world will they survive road hazard , water and most of all how do you deal with a flat ?.
If the company making these motor stop producing would you be able to get a replacement of exact size in case of failure.A high quality motor replacing the ice unit is a much more practical option for now if you want tu use your car dayli.You should also look into the power use of these hub motors since company are showing very impressive output but they also consume equaly when driven very hard.You coud get similar result using a high quality electric motor placed in without using the original transmission.Keep on with your project .

 

[Craig]

@moldiebrownie : I like how the creator of the 8-wheeled car is convinced it's the way of the future, and that an EV must be superior to replace IC cars...I wonder if he ever paused to think how 8 wheels are better than 4

@veperformance

will they survive road hazard , water

Err... they look water resistant? ^^ Seriously, I don't know... But I'll be driving in the mountain alot, so if they can't withstand water and salty snow, I guess I'll use a "normal" motor...

how do you deal with a flat ?.

Well, either you get run-on-flat tires (to be able to limp to a garage to replace the tire) or you carry around a (probably) heavy pump, and a spare (not great options, but that's all there is..) Or in PML's case, the wheel actually attaches to the motor, so it's easily replaceable.
As for e-traction, I'll probably be using the SM350 motor. It's not an in-wheel motor, so there shouldn't be any problems for tires and mechanical brakes.
I also browsed their website a bit, and it turns out they've been making these motors for 10years.. So in the (unlikely) event a motor fails, they'll probably still be in business to supply another one (at least I hope ^^)

You coud get similar result using a high quality electric motor placed in without using the original transmission

What do you mean? That the motor can be placed between the wheels to eliminate the transmission? Or that it's possible to use more efficient transmissions? One of the points of direct drives is that there's much less (or none at all) mechanical parts that are prone to break...(plus it removes a little weight)

Anyway, little update (I don't have much, since e-traction haven't answered my email yet...): After a little more browsing, I noticed that thewheel 500 is much too big for a car - it's what they used for their 2nd gen bus, and even there it's bigger than the original wheels.... So I'll probably use the non-wheel hub motor they make (sm350)...It's supposedly better suited for personal vehicles, but I'm waiting to know if it's powerful enough to take a minivan on mountain roads and motorways...

 

[Craig]

Hi,
My weblog is up, even though there's just 1 relevant post for the moment...
I'll post updates as I get more info (progress is pretty slow right now)

 

[sedonix]

The problem with wheel motors as I understand it is the principle of unsprung weight. The less weight that is unsprung that is the wheel, hub, brakes the better the ride and handling is. Putting a motor, even a light one in the wheel is going to cause major changes to the ride. Will need larger shock absorbers, and no matter how much effort you put into retuning the suspension , the ride will be worse. Get a book on auto suspension and handling. Ever seen race cars with the brake rotors on the inboard side of the drive shafts? This is why. Of course, you are gonna add a lot of battery weight on the sprung side of the car, so maybe you can get by with heavier wheels.

Greg C.

 

[Craig]

Actually there won't be any added unsprung weight, since I'll (well I hope I will) use 2 out-of-wheel motors (see my website for more details about them). With those I'll have all the advantages of in-wheel motors, eliminating the transmission, differential etc, but they wont add weight to the wheels themselves...