Silly ideas: Ebike wheels

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Silly ideas: Ebike wheels

Postby salixfire » 13 Jun 2018, 20:45

I know there's probably good reasons why this wouldn't work, or not advisable, but could you attach ebike motors/wheels to a wheelchair?

With prices coming down significantly for both e-bicycle and e-motorbikes motors, wheels hubs and controllers would it be possible to:
1) Attach 2x 1000w (or more) ebike wheels to a self propelled type wheelchair? As the wheels on those are generally shitty bike wheels with push rims?
2) Instead of using brushed motors, use e-motorbike wheels (up to 8000w :angel: ) on a powerchair?

Both using lithium batteries running 48v-72v.

Workable or completely insane in a bad way?

:)
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Re: Silly ideas: Ebike wheels

Postby Burgerman » 14 Jun 2018, 01:01

Dont know enough about them. But generally starting torque, control, etc isnt good enough at low speeds.
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Re: Silly ideas: Ebike wheels

Postby salixfire » 14 Jun 2018, 10:34

What sort of specs would be suitable for a wheelchair?

(Does the data on https://www.goldenmotor.com/ give enough detail?)
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Re: Silly ideas: Ebike wheels

Postby Burgerman » 14 Jun 2018, 11:03

None work well. Not even the specialist brushless invacare motors. You need some form of reduction gear. Direct drive doesent give adequate resoluton, or torque. Even at massive amps.
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Re: Silly ideas: Ebike wheels

Postby salixfire » 14 Jun 2018, 19:06

Not even for motorbike or high torque brushless motors? The ones Invacare etc use I doubt would be a good spec as they are only just coming into the brushless motor market but the ebike and e motorbike ones have had far more push to get them right. Could you use, rather than directly attached to the wheel, a gear/sprocket chain system and the motor mounted slightly offset?

As I said these are silly ideas but hey it's entertaining thinking of a 120km/h wheelchair :P
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Re: Silly ideas: Ebike wheels

Postby Burgerman » 14 Jun 2018, 20:24

Not even for motorbike or high torque brushless motors? The ones Invacare etc use I doubt would be a good spec as they are only just coming into the brushless motor market but the ebike and e motorbike ones have had far more push to get them right. Could you use, rather than directly attached to the wheel, a gear/sprocket chain system and the motor mounted slightly offset?

As I said these are silly ideas but hey it's entertaining thinking of a 120km/h wheelchair :P


If you remove the gearbox from a stock brushed motor you get the RPM needed to go 120kmph too. The problem is that you cannot get adequate torque, without a huge motor, and a massive stall current. So a reduction gear is needed. A brushless hub motor is no different.

Its easy to get speed with a hub motor. It is the motor. It wants to spin. And has no gear advantage. So behaves the same as a brushed geared motor we are used too, with no gearbox... And for cycle or motorcycle use thats all you need. They dont need accurate positioning control at .01mph next to your dinner. Its STARTING torque, (a brushless motor needs to move to know which way its going and how fast) and starting and at super low speed control, resolution, and accuracy that is the problem. And thats all very much needed for steering at very low speeds. So yes, it will work, if you gear it down with say sprockets, so its no longer fast, and now isnt much more efficient either because of the gearing. Direct drive hub motors are a big problem in a powerchair and invacares are far more advanced and developed than any of those golden motor offerings. Specifically optimised for torque, low RPM, control, high resolution, etc. At great cost over 20 years. We are now on the 3rd version. And they are still crap!
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Re: Silly ideas: Ebike wheels

Postby flagman1776 » 14 Jun 2018, 22:57

There are seemingly good wheels and tires intended for scooters & monkey bikes that are being adapted. The direct hub drives seem weak, although the latest incarnation of the TravelScoot uses a hub motor. Both the ones I have are the older model with belt drive & considerable reduction gearing.
TravelScoot1 3P8S LiFePO4 Hyperion 1420i
TravelScoot2 OEM LI & charging
1/2 interchange adapters
Pride Wrangler
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Re: Silly ideas: Ebike wheels

Postby Burgerman » 15 Jun 2018, 03:12

Dont think direct drive will ever be able to work very well for a powerchair, brushless or not. There are a few brushless systems available with gearbox, as we use now, for powerchairs comming from china. And some hub motors are available with reduction gears built in from various places. As used by the guy building the 6 wheel drive mountain chair. This puts the gears back... So reduces current, increases torque, improves resolution. But lowers the speed. http://mountainwheelchair.com/build-log ... ir-motors/

Image

The travel scoot is really a scooter. So high torque at small pulsewidths, and high resolution for accurate positioning or zero turning are not required. So they may work OK there, or on those manual chair adapters that bolt a wheel on the front.
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Re: Silly ideas: Ebike wheels

Postby gcebiker » 15 Jun 2018, 07:40

I built and had a patent on these, the patent i let lapse (so feel free to tinker), they use Ebike wheels.


Gearbox of a 26" wheel in a 16"Rim, giving a balance of torque and speed.
ezyRider 2015 build.jpg


Versions are made to suit the user, the above model comes apart and can be changed to a manual wheelchair.
Forks will accept from a 200w - 2KW motor. It was cheaper to build my own Alloy wheelchairs than to get a factory one and mod them...

The boat seat was the only available 'off the shelf' seat that will let this chair go through a regular, narrow shopping isle and inside a department store easily.

This particular version had a 408 Crystalyte motor laced into a 26" rim, would run from 24-48volts.
With a different controller it was capable of running up to 72v
Image042.jpg


Companies in the UK also developed one the "Viper" about 2005.
viper069.jpg


There are now many variations of these around the world.
http://gctek.me/dynamic-controls/shark/rc-wheelchair-controller/
My YouTube Ch -- https://www.youtube.com/user/gcebiker[/list]
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Re: Silly ideas: Ebike wheels

Postby ex-Gooserider » 19 Jun 2018, 00:50

One problem you will encounter is that pedal bike wheels are designed to be supported on each side, (as in forks) and so have relatively light thin axles. Manual chair wheels are designed to be supported only on one side, and have fat axles intended to take the side load... If you mount a pedal bike wheel on only one side, it will bend the axle....

In addition as others have said, the e-bike wheels are not real good at starting from a stop - they tend to assume that the rider will be giving them a bit of a push to help get them moving... They also tend to not do well at the sort of fine movement needed for tight spaces....

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Re: Silly ideas: Ebike wheels

Postby flagman1776 » 19 Jun 2018, 14:53

Ex-G makes an excellant point. My wife has a pony (driving) cart (somewhere in the barn) made with bicyle wheels. It had to have support on both sides to keep the axle from bending. Proper driving carts have much stronger axles, bigger bearings, bigger hubs.
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Re: Silly ideas: Ebike wheels

Postby ex-Gooserider » 26 Jun 2018, 08:03

As a for what it's worth, the HoverBoard project is using stock hoverboard motors, which are 3-phase, gearless / brushless w/ Hall effect sensors, and we have not (YET) seemed to encounter any sort of problem w/ the motors / electronics overheating or crapping out the way BM was describing with his Invacare GB motor chair....

Granted, Erik who has been the primary test rider is pretty light (not sure what he weighs, but he uses a 14" cushion) but I've watched him spinning in place, doing start & turn from stops etc. for 10 or 15 minutes at a time (biggest problem he has with spinning in place is getting dizzy czy ) and not seeing any sort of problems....

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Re: Silly ideas: Ebike wheels

Postby Burgerman » 26 Jun 2018, 09:12

Does it have 15 inch wheels? Where 1/4 of a wheel revolution is 14 inches... On a zero turn for eg that means a minor 10 degrees turn requires each wheel to slowly and accurately move 2 inches in opposite directions.

Once a motor is designed and configured for that and greater levels of positional accuracy the problems begin. (10 degrees is huge, sometimes you need only 1 degree accuracy to position yourself in a van, narrow door etc so the motor needs to be able to be positionable smoothly and precisely to .2 of an inch)

The types of motors we see in hubs from goldenmotor or bikes, intended for higher speeds, or hobby motors cant do this. And if they could they too would likely suffer the same high starting current compromise. Once past 0 to crawl speed, this issue goes away. So spinning around not a problem.
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Re: Silly ideas: Ebike wheels

Postby ex-Gooserider » 24 Jul 2018, 10:16

I haven't got the exact numbers off hand, but the boards we have been using are ranging from nominal 6" OD wheels to 8" so not as much load as an Invacare GB motor... OTOH I don't see any law saying that one couldn't use a smaller diameter wheel for driving a chair - and these boards have top speeds that are higher than most chairs, so if properly done with a suspension system, it might be possible.

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