Disability uses - Chairs, Bikes, death-buggies!

[ComfyButt]

Hi everyone,

I'm Tim. I'm an adventurous paraplegic that likes getting out and about (no batteries or motors yet, Manual wheelchair and cycles) but struggle in the stamina department!

I'm really interested in using ebike motors to help out and extend the range of my travels.

I have a couple different handcycles but would like to start out by making a single-wheel addon for my manual wheelchair. Handcycles are a bit complicated to jump straight into and I'd like to use a chair-motor as a learning exercise. Death-buggies come later!

There are a few commercially available options, which are the same price as a nice used car! I'm sure I can rig something up to do the job for a lot less and wanted to ask everyone's advice.

A few naive newbie questions:

1. Are hub motors suitable for prolonged low-speed use?
In the chair, I want to focus on torque and don't want more than 10mph speed-wise.

2. Can I just buy a hub motor then take it to my local bike-tech and ask him to spoke it into a wheel for me?
I'd like to use a single 10 or 12 inch wheel (guestimate, no idea on actual wheel sizes yet) behind and below the wheelchair's seat. I know lacing the spokes will become more difficult the smaller the space between the motor and the wheelhub. Leading me to another question:

3. Is it possible to put a tire directly onto any hub-motors?

4. What recommendations for hub-motors do you have, with these considerations?:
- low-speed, high-torque.
- No cycle gearset.
- Hub-motor preferred.
- Small wheel size.
- Battery size and form-factor not too restrictive (under-seat stowage)

Thanks to everyone, looking forward to experimenting and sharing some builds!

 

[Deleted member 4366]

If you take a normal hub-motor for a 26" wheel and put it in a wheel half the size, it'll make double the torque and half the speed.

You can buy them pre-laced to 16" rims or anybody that can build wheels, should be able to lace one for you, though the cost can vary a lot.

You can buy motors for Scooters that are exactly as you describe.

https://bmsbattery.com/ebike-kit/639-6-8-10-scooter-motor-ebike-kit.html

Bicycle hub-motors come in a range of speeds, so you need to know which speed variant you're dealing with. A 201 rpm one does about 15 mph in a 26" wheel, so if you put it in a 16" rim it would give about 10 mph. All you need to decide then is how much power you want. This one is quite small but can give masses of torque at 48v.

https://bmsbattery.com/ebike-kit/598-q128-48v500w-front-driving-v-brake-e-bike-motor-wheel-ebike-kit.html#/213-rpm-201

Note that it would be unusual for someone to put a 201 rpm motor in a 16" wheel, so you'd need to tell them how important that is for you, otherwise they'll assume you made a mistake and give you the 328 rpm one.

48v gives you more power and torque. You can always turn it down if it's too much. You don't have to use full power all the time.

If you're going to construct a hand pedalling system, you'll need a rear motor.

Use a disc brake rather than a rim brake, which will give you much more flexibility on fork size.

If you want to go with a hand pedal-assist function, you should get a controller with a LCD. If you want throttle-only, then you can use any controller. That Q128 motor above needs a controller about 20 amps to get the best out of it.

Batteries are simple. the more Ah, the further you go and the more they weigh; however, some smaller batteries struggle to supply the current that the controller takes from it, so always choose a battery that has a continuous current rating of at least 5 amps more than the controller's maximum.