Powerd wheelchair build

I am currently working on making a all terrain electronic wheelchair with relatively slow speed with high tourque. Speeds up to 15-20 mph max would be fine. So I was thinking about using center hub ebike motors with a single shaft, and fat tires. On the rear. Does anyone have experience with this kind of application? I've read about this in older forums and I'm sure we have better technology now. Like the side shaft ebike motors. Any help with how many watts, tire size, controllers, ect... Would be a great help. Thanks.

I'm interested but no idea on the drivetrain.

Could someone link to pics of examples?

jirwin82 said:

Any help with how many watts, tire size, controllers, ect...

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with the information provided so far, the best i can recommend is to go to http://ebikes.ca/simulator , read the entire page so you know what everything is and how to use it, and then play with various systems to see what kind of system will be needed to do what you want under the circumstances it will be used under (though it doesn't accoutn for wind, except via teh cda numbers in the custom-bike/etc dropdown).


the only hubmotros i know of that already have or can be made to use a single-ended axle, or stub axle, are some of the various goldenmotor and other chinese-brand stuff already made for powerchairs and the like, or the grin tech all-axle hubmotor at http://ebikes.ca which you can design any axle you like for, and there's a tadpole trike (catrike?) thread here on es using a pair with custom made axles/adapters.

you could design and make your own single-sided axle for any hubmotor, along with a new cover on that side for a bigger-id bearing to fit over the new larger axle.

keep in mind that speeds as fast as 20mph with a single sided axle on anything but perfect roads are going to eventually stress the axle at the point it enters the bearing and the point it exits the frame, unless you have suspension on those wheels, and probably snap them off, on most of the existing singlesided axle motors. the axles just aren't very well made or designed.

as long as you mkae better axles or use stuff ilke the all-axle hubwhere you would be making your own to start with, it shouldn't be an issue...but if you use the generic chinese stuff, it may well have catastrophic failure under teh wrong conditions.

I can see the issues you brought up with the axles searing off with a single shaft motor. I would definitely put suspension springs, shocks, ect... Maybe cambered wheels would help in strenghth and stability in that type of design also? I was also thinking about welding forks on to use regular bike hub motors? Trike style wouldn't work for me because I couldn't lift my legs over the center frame cross bar. For steering what I had in mind would be individual controlers and throttles so it would steer like a zero turn radius lawnmower or tank. That's why I was thinking individual motors instead of a drive axle. I will do more research and make some drawings of possibilities I have in mind. Any extra advice or ideas about this would be greatly appreciated. Thanks in advance.

Hubmotors for wheelchair already exist, though a pair of hubmotors designed for golf cart size vehicles may be more suitable for your off-road mobility unit, including really wide tire selection. There's no need to pull off some axle conversion.

jirwin82 said:

I can see the issues you brought up with the axles searing off with a single shaft motor. I would definitely put suspension springs, shocks, ect... Maybe cambered wheels would help in strenghth and stability in that type of design also?

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camber will increase the stress on the axles. but it will help with stability, giving a wider weheelbase for the same axle width. however it reduces the space between the tires at the top, so less space for the user.

if the axles are thick enough for the weight on them and the impact forces (whcih basically increase the weight on the stress points, dependingo n the g-force created during impact), then they won't break. the problem is usually the desing of the axle, since most are made as sharply stepped sections, and the sharp steps are stress risers focusing the stress along the sharp corner. making those all rounded helps fix that.

I was also thinking about welding forks on to use regular bike hub motors?

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that will be stronger with the axles supported on both sides.

For steering what I had in mind would be individual controlers and throttles so it would steer like a zero turn radius lawnmower or tank.

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that works well at lower speeds. at higher speeds you have to compensate for the reaction time either by learning it yoruself or by using a comptuer or analaog circtuit to do it for you. you'd have to design and tune that experimentally, most likely, unless you can figure out the math fo fr determining the problem and the anser. might nto turn out to be a big deal, but i suspect on that shrot a wheelbase it'll be qutie a prblem over just a few mph.

others have built hotrod wheelcharsi and powercharis os you could google search for those and see if any of them show or tell how they dealt with it, or if ti was a problem, depending ont he speds they went.


at slow speed it's totally normal to steer wieht the wheels; peope do it with handpowered ones quite easily, and powerhcaris just about all use individually contorlled mtoros for each large wheel, soemties on teh small ones too, though its usually ajoystick for one-handed fairly rpeceise steering on those, depending on the input abiltyies of the oeprator.

Thank you for the advice. The website's you sent me to were very useful. By the way, I was only thinking of top speed of 15 to 20mph on a flat smooth road. Otherwise 3 to 5mph on nature trails with slight grades and rough terrains. So I was thinking 20" rims with wide tires on the back and maybe 12" rims on the front. Made with a modified light weight sport wheelchair frame, welding some mountain bike parts onto it. I'm on disability with a tight budget and I'm sure I could salvage bike parts. I'm confident I should be able to build this much cheaper compared to $6000 and up products on the market.

Does anyone know about the quality of leaf bike center hub motors? I've seen a new single shaft motor on the market now. They are relatively inexpensive and come with controllers, throttles, and I think electronic brakes with each motor.

Does anyone know about the quality of leaf bike center hub motors? I've seen a new single shaft motor they have on the market now thats fairly inexpensive. I'm on a tight fixed income. So maybey I could use some salvaged mountain bike parts as well. I'm looking into building an low tourque, low speed, decently rough terrain eletric wheelchair. Maybe with a little top end speed on smoother roads. I'm not sure how durable the side shaft motor will work in this application? Maybe with 2 motors and controllers, with a modified axle and suspension? Any advice would be greatly appreciated. Thanks in advance.

If you want to keep things budget friendly why not try to find a second hand lightly used mobility scooter or electric wheelchair with dead batteries? And then convert it to your needs?
Building an electric wheelchair with reliable control (steering with the powered wheels) is a challenge...

Are you in a wheelchair? or can you sit in what would be essentially an office chair on a trike? There is a trike option out there, if you can sit on one, that is costly, but not like the medical stuff prices.

Pricy wheelchair adapters are out there. But you could copy one. Use 20" wheel for higher torque and lower speed.

I am in a wheelchair. I've seen the trike options that look pretty cool but I couldn't easily get on one. That's why I was thinking about bike center hub motors. Also because I could put better all terrain tires on it. Steering is what seems to puzzle me the most. That's also why I was thinking front bike motors may be easier to adapt on the back of a wheelchair since I wouldn't be using any chains. I also seen some single side axle bike motors on the market. I don't know how they would fit on a wheelchair axle though?

I have though of used mobility scooters, but they hurt really bad to sit on. Also they all seem to have really small wheels that control them. Wheelchairs that I can transfer into alot easier is why I'm trying to avoid a scooter.

If you're in a wheelchair and have trouble sitting on a mobility scooter and transferring to another (wheel)chair then maybe it would be better to get a motorized handbike that fits your own wheelchair.









If you're in an electric wheelchair already and/or need to be able to climb rough terrain then this won't work of course.

I will definitely look into these. Probably my best way to go, if it's easy to set up. Thanks alot.

Might get medical insurance to pay for the wheelchair attachments too.

That's what I was leading into when I asked if you were in a chair, or a person who can walk some with difficulty, but needs different type mobility solutions. We've seen some really cool bikes and trikes for those that are just a bit more able to transfer to anything or even walk for short distances, and sit on anything. One was a bike, but when it came to a stop, stabilizing wheels popped out. There is a Utah company that specializes in delta trikes with hand cranks, which activate motor power. Those trikes struck me as hard to transfer to, but perhaps the users have help that just goes with them on a regular bike or trike.

Get the commercial attachment since you are in a chair, insurance will never pay for some home made thing. They have sourced the lower rpm, small size wheel needed. Bike stuff all too big, and too high rpm.

For others who may read later, there are also some trikes out there specifically designed for that gap between a mobility scoot designed for inside or paved surface only, and full sized adult trikes. They have oversize tires for turf or gravel surfaces, and still break down to fit in a car trunk.

Stuff is out there, and we have seen nearly all of it. Once we know your specific needs, we can help you search out solutions, especially if insurance makes budgets for it less a problem.

Once I even wondered if it could be done, to make a delta trike, with a platform the wheelchair just rolled onto. Almost like one of those low skid steer trikes, but with a low wheelchair ramp up the back of it.

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There is a lot possible as a solution for mobility. But you need to know what will work in your situation. What terrain will you be riding how steep will you need to climb on what type of soil etc.

dogman dan said:

Once I even wondered if it could be done, to make a delta trike, with a platform the wheelchair just rolled onto. Almost like one of those low skid steer trikes, but with a low wheelchair ramp up the back of it.

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somthing like spdas' trike here?
https://endless-sphere.com/forums/viewtopic.php?f=10&t=83658&p=1230027&hilit=trike#p1225496

Yeah, just like that AW. No doubt, I'd seen one somewhere, most likely in a picture you posted years ago.

And I vaguely recall somebody else here was designing something like that for his kid, but I cant recall if it was a trike or a quadricycle type thing. I seem to remember two small rear drive wheels on that one.

But again, several brands of the hub wheel attachments out there, and if med insurance will buy one, start there for sure. Of if they will buy you one, that klick monster looks real fun. A fat tire wheelchair sounds like a real good starting point to me.

Just a thought on that, does anyone do handwheel power control in the same way we have pedal power control, ie. the harder you pedal/push the more power goes to the motor? Seems like the ideal, no additional parts for steering etc. and possibly a bolt-on conversion for any chair but I don't recall seeing anything like that available.

A bit expensive but electric assist wheelchair wheels do exist. You could lace them in 20" fatbike rims with fatbike tires and use a beach front wheel attachment to go over rough terrain.

https://www.sunrisemedical.com/manual-wheelchairs/quickie/manual-power-assist/xtender

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https://www.sunrisemedical.eu/wheelchairs/quickie/wheelchair-power-assist-wheeldrive



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https://www.invictusactive.com/product/freewheel-attachment-uk-reviews/

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stan.distortion said:

Just a thought on that, does anyone do handwheel power control in the same way we have pedal power control, ie. the harder you pedal/push the more power goes to the motor? Seems like the ideal, no additional parts for steering etc. and possibly a bolt-on conversion for any chair but I don't recall seeing anything like that available.

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if you mean hand-cranks, then:
https://endless-sphere.com/forums/search.php?keywords=handbike&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search


if you mean sensing your push on the handrail of the wheelchair wheels, then that's how some of the various electric wheelchair wheel replacements / systems work. i don't remember any of their names for sure; i htink one was e-motion.

none are more htan just basic low-power assist to help roll you along at walking speed, because if they were any mroe than taht, they'd rip the handrail out of your grip, or injure your hands/wrists/arms/shoulders/etc if you didn't or couldn't let go fast enough.

SlowCo said:

A bit expensive but electric assist wheelchair wheels do exist. You could lace them in 20" fatbike rims with fatbike tires and use a beach front wheel attachment to go over rough terrain.

https://www.sunrisemedical.com/manual-wheelchairs/quickie/manual-power-assist/xtender

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Xtender-Beauty.jpg



https://www.sunrisemedical.eu/wheelchairs/quickie/wheelchair-power-assist-wheeldrive



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https://www.invictusactive.com/product/freewheel-attachment-uk-reviews/

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FreeWheel-over-gravel-01.png

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Thanks Could be a fairly simple add-on for hub motor wheels, I'm not sure how good the response times are on the skateboard hand throttle doohickies, they could be ideal for the job. @amberwoolf, yes, a throttle system for the handrail. The motion control (PID) would probably need quite a bit of fine tuning but everything else should be pretty much plug and play with off the shelf ebike parts.

stan.distortion said:

Just a thought on that, does anyone do handwheel power control in the same way we have pedal power control, ie. the harder you pedal/push the more power goes to the motor? Seems like the ideal, no additional parts for steering etc. and possibly a bolt-on conversion for any chair but I don't recall seeing anything like that available.

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I saw a system like you describe (mid-drive handcycle) at Interbike three or so years ago, but can't remember the manufacturer. You should be able to locate on the web if they're still around.