15" car hub motor \$799 - Page 2 - DIY Electric Car Forums

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#11
07-16-2012, 10:08 PM
 AussieRav4 Junior Member Join Date: Jul 2012 Location: Brisbane, QLD, Australia Posts: 12
Re: 15" car hub motor \$799

I will agree with you that the price is high.
I am so new to the whole EV conversion goal that i don't have a full understanding of what you just said.

all i can really work out is that because there are numbers that don't add up there may be some over optimistic claims made by the kelly company regarding these motors regarding their use up to and including 160km/h [even i think that figure is a dream from this motor]. I just want to have the car as a way of getting around and going shopping/work and still be able to use it as a semi family car on a weekend or for putting a MTB bike on the roof and going for a ride in the mountains. [refer to my post in the conversion forum, http://www.diyelectriccar.com/forums...ase-76422.html

the hard part is that i would like to try and convert a short wheelbase Rav4 to a EV and keep the AWD system. the idea of a hub motor seemed logical. and the idea of efficiency of the motors has yet to really enter my thinking process.

but if there are concerns with these motors it might be best to look at a more conventional EV conversion.

#12
07-16-2012, 10:38 PM
 PStechPaul Senior Member Join Date: May 2012 Location: Cockeysville, MD 21030 Posts: 2,939
Re: 15" car hub motor \$799

The maximum torque of the hub motor is 78 N-m or 57 lb-ft. If the tire is 24" diameter the amount of force it can exert is 57 lb. Assume you have four of these motors you will have a force of 228 lb. If your vehicle is 2280 lb, it would be just barely enough for a 10% grade.

The speed is determined by the circumference of the tire, about 6.3 feet, so at 1300 RPM that's 8190 ft/min or 93 MPH. So 160 kM/hr is believable. But you really need more torque.

 I thought these motors were designed to connect to the wheel through a CV joint. But that was the WEEL motor. If that's the case you don't need a hub motor.

The "hubcap motor" project from Turquoise is interesting. I also had an idea for a bolt-on hybrid conversion kit, but adding the weight (and size) of a motor on the outside of the wheel may adversely affect the driving characteristics.

Good luck!

Last edited by PStechPaul; 07-16-2012 at 11:09 PM.
#13
07-16-2012, 10:55 PM
 AussieRav4 Junior Member Join Date: Jul 2012 Location: Brisbane, QLD, Australia Posts: 12
Re: 15" car hub motor \$799

Cheers.
The Rav4 is about 2600 pounds [i think, it might be less as i can't confirm the figures]. with this figure in mind the grade is now a good thinking point.

might be worth looking for a new plan of action regarding transmission conversion list. who knows, it might be worth looking into your idea of preserving the CV joints and attaching a motor to each of them. who knows.

#14
07-17-2012, 12:06 AM
 Tedktis Senior Member Join Date: Jan 2012 Location: Asheville, NC Posts: 294
Re: 15" car hub motor \$799

Without a transmission your going to need more torque, which = more \$. I don't think the hub motors can withstand the constant 'bumps' in the road or rain to be reliable. There is also unsprung weight to consider. I'd stick with the transmission and AWD and bolt one motor on. Unless you have the resources and time, maybe you'll find the solution? Good luck.
#15
07-17-2012, 12:16 AM
 AussieRav4 Junior Member Join Date: Jul 2012 Location: Brisbane, QLD, Australia Posts: 12
Re: 15" car hub motor \$799

I agree.
its time to get technical and work out the best electric motor to buy and find/pay someone to make a mounting plate and adaptors for my Rav4. it will let me keep a mechanical reverse gear and potentially have enough grunt to get up hills.

i will need to look at adapting the conversion by gdirwin to suit my car and local conditions. both cars are more or less the same. its just his was the full size Rav4 and i have the short wheelbase.

just need to think about the coupling and the touque convertor.

I was thinking about the rain and the unsprung weight earlier today. I agree with the idea. I still want to have some degree of ruggedness to the car.
aww well back to plan A.

Last edited by AussieRav4; 07-17-2012 at 12:17 AM. Reason: spelling
#16
07-17-2012, 08:19 AM
 ruckus Senior Member Join Date: Apr 2009 Posts: 654
Re: 15" car hub motor \$799

The most powerful (claimed) hub motor I have found is the Keguang KG315. They claim 20kw and 380nm, 250v and 1800rpm.

Making the giant assumption it actually works as advertised, I don't see how to mount it to a regular car spindle since they are all male (outies). What am I missing here? Has anybody got this to mount up?

The other issue is the need for multiple motors and controllers. That kinda defeats any price/simplicity advantage.

If it could be done though, the additional weight and space freed up by ditching the tranny/drivelines is HUGE. Think of all that battery space...

Cheers
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Last edited by ruckus; 07-17-2012 at 10:29 AM.
#17
07-17-2012, 09:10 AM
 mk4gti Senior Member Join Date: May 2011 Posts: 240
Re: 15" car hub motor \$799

Quote:
 Originally Posted by ruckus I don't see how to mount it to a regular car spindle since they are all male (outies). What am I missing here? Has anybody got this to mount up?
I'd like to know as well. The cars I worked on in my lifetime have solid (not hollow) drive shafts at the front hub and solid spindles at the rear wheels. There wouldn't be place to route the wires.

It looks like they mount the motor right on the brake rotor, which would make the wheel poke. Teenagers seem to enjoy this style - I think it looks goofy.

As someone else mentioned, these wires are way too small to power a RAV-4 for example, even at the four wheels.
#18
07-17-2012, 03:10 PM
 Tedktis Senior Member Join Date: Jan 2012 Location: Asheville, NC Posts: 294
Re: 15" car hub motor \$799

Quote:
 Originally Posted by AussieRav4 I agree. its time to get technical and work out the best electric motor to buy and find/pay someone to make a mounting plate and adaptors for my Rav4. it will let me keep a mechanical reverse gear and potentially have enough grunt to get up hills. i will need to look at adapting the conversion by gdirwin to suit my car and local conditions. both cars are more or less the same. its just his was the full size Rav4 and i have the short wheelbase. just need to think about the coupling and the touque convertor. I was thinking about the rain and the unsprung weight earlier today. I agree with the idea. I still want to have some degree of ruggedness to the car. aww well back to plan A.
Nothing wrong with thinking outside the box, you may very well have something. I just hate to see ppl get part way into a build and bail. Although that's where I get good prices on components.
#19
07-17-2012, 05:09 PM
 AussieRav4 Junior Member Join Date: Jul 2012 Location: Brisbane, QLD, Australia Posts: 12
Re: 15" car hub motor \$799

Ruckus,
thank you for helping with this additional product. it didn't come up in any of my searches.
it looks like a good piece of kit. its something that i would consider. I also guessing its EV weight considerations would be minimised by having 4 of these in the car.

mk4gti,
your right about mounting them in a car but I'm guessing something could be fabricated. If I'm not wrong i seem to remember my dads land cruiser having a shaft housing that was hollow. at a guess this would be a place to install the motors into and still provide a place to route the wires.?
its not possible in my rav4 and it still leaves a question as to how to mount the fronts so they steer but I'm guessing something could be made.

I have seen these hubs as a style in mock-ups on various vehicles in shows and I've always thought there is great promise in these hubs to convert the existing fleet or to provide for better storage of the power source.

--

the thought as to how much weight would be removed from the car with all its ICE and transmission removed is a good thought but if 140kg of motors are installed + controlling gear + mechanical/electrical augmentation of existing control mechanisms + batteries I'm wondering is the advantage is neutralised.

don't get me wrong, this is project of mine is to be very carefully thought out and will be my version of building a lotus 7. [now theres a thought - an EV lotus 7 replica powered in the rear by 2 in hub motors on a "live axel" suspension setup].
#20
07-17-2012, 08:32 PM
 ruckus Senior Member Join Date: Apr 2009 Posts: 654
Re: 15" car hub motor \$799

Well, the idea of hub motors is a good one, but it would be best used on an 'experimental' platform which is light-weight and small. I wouldn't go getting all fired up and try to convert a daily driver suv to hub motors without a test vehicle.

I am not one to follow the mainstream, but hub motors are the lunatic fringe.

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