Hubba hubba hubba....that is, hub motors :) - Fuel Economy, Hypermiling, EcoModding News and Forum

Pengyou · 04-22-2008, 01:36 PM

I have seen lots of posts and ads about using hub motors to power a car. I am looking to hear from someone who has actually done it. Have you?

Also...why is it so slow in catching on? In theory it seems like a great idea - can trash the engine as well as the tranny and all related "stuff".

I am hoping to pick up an old Dodge Caravan and convert it to electric. I would love to use hub motors. If it were useful it would simplify the conversion....don't have to worry about adapters to the tranny, etc and would help balance the weight in the car.

SVOboy · 04-22-2008, 02:20 PM

I've never seen anyone DIY it, but if anyone has, I'd love to see a link.

I feel like suspension issues would be the main roadblock with the DIY approach.

Welcome to the site!

dremd · 04-22-2008, 07:13 PM

I'd Love a Pair. I'll make them work.

Ok, now where do I buy a set?

I've seen a pair in the Flesh, KUHMO had them at SEMA a while back, but now seams to deny that they ever existed. . .

Subscribed.

Arminius · 04-22-2008, 07:28 PM

Quote:

Originally Posted by SVOboy

I've never seen anyone DIY it, but if anyone has, I'd love to see a link.

I feel like suspension issues would be the main roadblock with the DIY approach.

Welcome to the site!

That brings up a question I had. I sometimes consider contacting people that could talk about things like this, but I get worried about them disturbing the site if they could gain financially from it.

LostCause · 04-23-2008, 12:49 AM

Issues that come off the top of my head include:

1.) Lower efficiency

While motors (especially the AC variety) tend to have very linear torque curves, they have a speed of most efficient operation. Using a hub motor, which almost certainly means it will be direct drive, forces the motor to operate under a much wider speed range. Generally, the faster the motor turns, the lower its efficiency due to friction.

Many of the top solar cars use direct drive hub motors, though. I've forgotten the motor brand, but it is extremely expensive for its output and extremely efficient.

2.) Higher Unsprung Mass

Hub motors are physically attached to the wheels, increasing their weight. From a performance and design perspective, lowering the unsprung weight to sprung weight ratio is desirable. Heavy wheels exert large forces on suspension members, causing their required strength (and thus weight) to increase.

3.) More Complex Drivetrain

Some high-end electric cars, such as the Tesla Roadster, use hub motors. The average DIYer most likely shies away from the technology because it is easier to drop in an engine replacement than redesign the drivetrain. Axles would have to be lost, kingpins and steering knuckles redesigned to accomodate the motor and its wiring, and special rotating electrical contacts fabricated to power the hub motors. While it is not impossible, hub motors probably rate low on the cost/benefit ratio list.

- LostCause

Pengyou · 04-23-2008, 12:51 AM

Here are some sources for the hub wheels. The alibaba site is not for sales to individuals but if you follow up the company's listed they may be willing to sell you some.

http://www.alibaba.com/trade/search?...uct_en&CatId=0
http://www.pmlflightlink.com/motors/hipa_drive.html

Ryland · 04-23-2008, 01:07 AM

Most motors are geared down to allow for a smaller/cheaper motor, a hub motor has to be a low speed motor so that raises the cost, then you have to have two of them and two controllers, and two of alot of other parts so that doubles the cost.

Looking at one of these motors I notice that the top speed is around 850rpm, 155/80 R13 tires are around 900 rotations per mile, so under ideal conditions this motor could push you at just over 50mph? that is if the car is not to heavy, my 1,400 pound comuti-car has a 6,000 watt motor, these come in 3000W/4000W/5000W/6000W/8000W/10KW
The other promising looking motor is a 5,000 watt motor with a top speed of 800rpm and a "12" car rim" not what most people would want for an electric vehicle, but it could work.
Alot of those companies will ship you a "sample" altho the shipping will almost kill you, we had a box that was maybe 2 cubic feet shipped with some cabinet door samples, shipping was well over $300 plus the cost of the samples.

Hub motors work great for bicycles because they make it simple, I think they would work well for a small electric motorcycle as well, maybe two of them for a motorcycle.

Christ · 12-30-2008, 07:41 PM

Would you really need two controllers for two motors? They're going to be turning at the same speed all the time, so couldn't you use a single controller/contactor/whatever?

The tesla uses a 14k RPM AC powered beast... that thing isnt' a motor, it's a Marvel. And I'm pretty sure it's made by GE, as are the 200HP AC motors that Chevy used, and I'm pretty sure the big3's electric fleet are GE powered also.

Dodge made an E-version of the Caravan way back when - but I have only been able to find a sparse amount of info on it. Consequently, they also made a few performance versions... oddly enough.

dremd · 12-30-2008, 07:58 PM

Quote:

Originally Posted by Christ

Would you really need two controllers for two motors? They're going to be turning at the same speed all the time, so couldn't you use a single controller/contactor/whatever?

The tesla uses a 14k RPM AC powered beast... that thing isnt' a motor, it's a Marvel. And I'm pretty sure it's made by GE, as are the 200HP AC motors that Chevy used, and I'm pretty sure the big3's electric fleet are GE powered also.

Dodge made an E-version of the Caravan way back when - but I have only been able to find a sparse amount of info on it. Consequently, they also made a few performance versions... oddly enough.

Yes with ac motors you need 1controller per motor unless you lock them on a single shaft.

Christ · 12-30-2008, 08:37 PM

So you couldn't use a single controller and two contactors?

controller would send the signal to both contactors, which would turn the engine's power on/off as necessary... I don't see how this wouldn't work out...

A long time ago, a local mechanic told me that you couldn't put two engines on a car without them being coupled somehow... I laughed at him and drove a go-kart with two 5 hp briggs direct-drive engines on it into his shop, one engine controlling each rear wheel.

This controller per motor thing seems kind of speculative, honestly, I just don't see a real reason that it couldn't work.