Front Drive for wheelchair

[Somo]

Hi, I need to replace a Bionx system on my wheelchair front drive attachment.
Looking for high torque/power geared hub motor with 135mm drop out, 48v system ( I have batteries) , twist throttle. Ideally programmable with reverse but not deal breaking. Front drive has no pedals.

Any recommendations?

 

[amberwolf]

To get reverse with a geared hubmotor, you have to use one with no freewheeling clutch, like the GMAC from Grin Tech, http://ebikes.ca. (or open up a clutched motor and lock the clutch so it can't freewheel).

A motor like this means that it will no longer be able to roll freely forward when not powered (like if there is a system failure, power loss, etc), it could take significant effort to overcome the drag of the motor (usually more than with a DD hubmotor because of the internal gearing, etc).

If it will never be used manually, only with power, then it doesn't matter, but if it has to be hand-pushed by the rider without power at any point, it could be a problem if the resistance is high enough.

 

[Somo]

Wow, thank you. I did not know that- being able to manually push is a bonus at times. I will cancel the reverse request!!

 

[Chalo]

Wow, thank you. I did not know that- being able to manually push is a bonus at times. I will cancel the reverse request!!

A high efficiency direct drive motor like Leaf 1500W has pretty low drag when unpowered. If you do want reverse, that's the way to go. As a bonus, Leaf will give you a special winding by request to deliver the top speed you want with the maximum possible torque per amp.

That motor is too big for a 16 inch wheel, but it works fine in a 20 inch wheel with radial lacing.

It seems to me that you could arrange a front drive that's capable of turning all the way around, and that would give you reverse on demand.

 

[Somo]

Interesting - I was advised to stick with a geared hub as more power efficient with stops and starts. I like going 32k but also often its stop and starts. Is that not an issue with this DD? Thanks

 

[Chalo]

Interesting - I was advised to stick with a geared hub as more power efficient with stops and starts. I like going 32k but also often its stop and starts. Is that not an issue with this DD? Thanks

A Leaf 1500W motor is maximum 91 percent efficient, give or take, and has a wide RPM of very good efficiency. A geared hub motor might climb quickly into its most efficient speed range, but its maximum efficiency will be lower, making it a wash for most use cases.

For cruising in the upper quarter of your speed range, a good direct drive motor will be about the most efficient thing you can use.

 

[MxusMick]

Hoverboards are cheap, can be found used on Walmart.com, Craigslist, even on the curb. Both 6.5" wheels are mini DDmotors, plugged to an ebike controller they go crazy fast. They plug in just like ebikes and for between $50-100 you will have two motors. A 3 phase bridge rectifier will turn the spare wheel into a poormans windmill generator!