WHEELCHAIR SUITABLE gearless brushless hub motors - HELP

[coolmobility]

Hi guys, I'm an Australian wheelchair designer (and user for 30 years since a hang gliding accident in 1977) and have only yesterday found this very informative forum. Spent hours reading all your input and would appreciate your experience and input.

I have designed a light weight power wheelchair where the third prototype uses a 24V 19Ah NiMH battery pack using Cobasys batteries. Looking at developing a production prototype using C-LiFePO4 pack of about 24V 29Ah. On the battery side I'm confident, especially after reding all your stuff.

Motors are my major problem and you'll see on my website http://www.coolmobility.com.au/WheelchairP3Video.htm that I used hub motors on my last prototype. These were prototypes developed by Georgia Tech using rare earth magnets but have a wek point of the internal gearing. I'd like to use gearless brushless hub motors and have been researching such hub motors for quite a while.

I'd appreciate any input as to potentially the best motors where torque is primary (especially from dead stop at slow speed) up to a speed (using 16" wheels) of about 16 kph (10 mph). Am I being unrealistic in hoping to find a basic hub motor that I can then have modified to meet my single sided axle requirements - note that I'll be using two hub motors?

Your input would be invaluable and I realise that I may have to move away from conventional 24V proportional controllers to a custom built 36V system to realise my needs from the two hub motors. Before I start buying sample motors to test on a trike arrangement on my wheechair initially, I'd appreciate input from this forum's members with all your experience in real use of a variety of these motors.

I realise it is a paradym shift for you guys, from max speed to max torque at low speed but the reality is that wheelchairs mainly function at 0-5 km but want decent speed outside. I want to show that the days of using PM brushed motors driving worm drive gearboxes, with all those innefficiencies, and lead acid batteries is hanging onto old technology.

You are welcome to contact me off forum on colin@coolmobility.com.au

Cheers from the land of Oz, Colin.

[OneEye]

An interesting question, most of the experience on this forum is with the bike kits. 

A great resource for the information you are looking for might be the Endless Sphere forums at http://endless-sphere.com/forums/ there are a variety of interests there, from e-bikes to scooter and electric motorcycle enthusiasts.  There are a number of active users with electrical engineering design experience and a lot of knowledge about a wide variety of motors.  You might get more feedback if you post there with a link to the page advertising the hub-motors you would like to choose between.

FYI, this forum is dying a somewhat slow death due to lack of vendor support.  It doesn't help that the primary advocate for the product and this forum has soured on the company's customer service and overall reliability rate.  That's not to say specificially that the hubmotors on the site may or may not work for you, but many users have been disappointed in the as-received condition of their gear.  We usually hear pretty good reviews if a buyer gets one and it works, but sometimes the kit arrives either DOA or nearly dead-on-arrival, requiring hall sensor replacement, spoke or rim repairs, or other work.

[coolmobility]

Thanks for the redirect as it is a very confusing path trying to break with "accepted" conventional motors for wheelchairs as the large manufacturers of wheelchairs are so set in their ways and have not engendered the manufacturing community with much incentive to innovate.

I'll have a try on Endless Sphere but still welcome any feedback on this forum.

I'll need to considerably adapt/modify any bike hub motor to provide a power off wheel lock system to meet safety standards and would like to use a solenoid released disk brake system so if anyone has any ideas as to suitable disc brak calipers I'd be interested in that too.

Cheers

[coolmobility]

The Golden Motor wheelchair version is too low a power and, to my understanding, is brushed and geared 24V hub motors.

A more sophisticated and 15" version is what I'm after with a safety lock in abscence of power.