Wheelchair with Handcycle

Aloha all. A newbee here with lotsa questions, but I will limit it to 2.
I have converted my Toyota Yaris to electric, so I am not totally ignorant about controllers, motors, Lithium, but need a quick course in building my "Clip-on hub-motor" attaching to my wheelchair.

I just bought a cheap (relatively) Chinese handcycle (in the Pix below) with the 36v 350W hub motor with 12" wheel that goes 15mph, mostly as a test to see if it would be useful and I LOVE it but need to make it safer and faster as well as beef up the wheelchair for safety.

Here's a couple of questions:

1) looking at the hub motors on ebay, probably 500w, how do I judge which is faster? I assume it is the RPM @ given voltage..... some are around only 36v 290 rpm. That will be slower than my current 350w with (calculated 400rpm)
What kind of RPM should I be looking for or how do I judge to get to the desired speed of 20-25 mph, using a larger 16" wheel. (20" and up are too large for my application)

2) Brushless motors... does that mean that they are all "Hall-effect"?

(not that is not me on the left)

Thanks, Francis

spdas said:

Aloha all.......I have converted my Toyota Yaris to electric, so I am not totally ignorant about controllers, motors, Lithium, but need a quick course in building my "Clip-on hub-motor" attaching to my wheelchair.

Click to expand...

Converted your Yaris to electric? Wow you are one to be impressed by!

.....Here's a couple of questions: 1) looking at the hub motors on ebay, probably 500w, how do I judge which is faster? I assume it is the RPM @ given voltage..... some are around only 36v 290 rpm. That will be slower than my current 350w with (calculated 400rpm)
What kind of RPM should I be looking for or how do I judge to get to the desired speed of 20-25 mph, using a larger 16" wheel. (20" and up are too large for my application)

Click to expand...

All things being equal maximum rpm is the final arbiter, but other things need to be taken into account. Your normal route is important because a fast wind motor may not have the torque to pull up hills like a slow wind motor or a geared hub motor.

If you are on flat terrain most of the time then voltage and amperage are the things you should look for. A 36v 26A (800 watt) controller won't give you the watts of a 36v 30A (1000 watt ) controller. Then again it also depends on the type of motor you have.

If you have hills, maybe you don't want a fast wind motor that has high RPM's but low torque.

Battery chemistry is also a consideration. I run on LiFePO4 because of it's relive safety. Other chemistry can deliver current faster which could get you up to speed faster.

ebikes.ca has a motor simulator that you should play around with to some results.

http://www.ebikes.ca/tools/simulator.html

2) Brushless motors... does that mean that they are all "Hall-effect"?

Click to expand...

As far as I know. Brushed motors have a built in commutator that flips the current from winding to winding to get a brushed motor to move.

Brushless motors use bipolar Hall effect sensors like the SS49E to trigger the logic circuit which triggers the driver circuit in you controller to drive your brushless motor.

So I have some questions:
How flat or hilly is your normal commute or path for your chair?
How much do you and the chair weigh?
How much is your budget?
When you say you need to make your chair safer, what specifically do you mean?
Are you married to that chair or could you change to something different if need be?

So I have some questions:
How flat or hilly is your normal commute or path for your chair?
Flat.

How much do you and the chair weigh?
chair is 35 and I am 135 the power pod is 25# total 195#

How much is your budget?
$400 or so

When you say you need to make your chair safer, what specifically do you mean?
1) Make a better/stronger connection between chair and pod
2) Put on fatter tires with lower air pressure to smooth out the bumps
3) Put more caster on the wheels (or is that camber?) anyway the wheels will be wider at the bottom to give it a wider stance

Are you married to that chair or could you change to something different if need be?
1) Married to it as it fits into my Moped trike (see pix) and fits into my 650 that I am building

More questions. Would I not get 35% more rpm's by going to 48v battery and controller.
But right now at 15mph and 36v/500w/12 in wheel, I think i am turning about 400 RPM's.
Will this (probably cheap motor) take more Volts?
(the motor and controller does not get very hot)
How do I judge? I will read your answer and try understand.

Yes my Yaris hauls ass, has a zilla controller, Warp9 motor and 46x200ah Calb batteries.

thanks
Francis

Hi Francis

Sorry for the OT, but where did you find that handcycle? Need me one of those

-Martin

Maybe you just need to run your motor on more volts, to get the speed you need. Get a controller that goes from 36 to 72v, and then start experimenting.

Not too strong a controller though so you don't fry your current motor, perhaps this one. http://www.ebikes.ca/shop/ebike-parts/controllers/c7225-nc.html

It could also be paired with a cycleanalyst, allowing you to also control max amps, if your motor starts heating up too much, turn amps down.

Note the controller runs sensored and sensorless. Yes, brushless motors can run without the halls, but sensored operation is best.

mkaaskh said:

Hi Francis

Sorry for the OT, but where did you find that handcycle? Need me one of those

-Martin

Click to expand...

Aloha, I found mine on ebay. But do a google for "Sherpa or Rio or Bantec. I would try craigslist nationally too, as the wheelchair dealers want Crazy high prices for these.

francis

dogman dan said:

Maybe you just need to run your motor on more volts, to get the speed you need. Get a controller that goes from 36 to 72v, and then start experimenting.

Not too strong a controller though so you don't fry your current motor, perhaps this one. http://www.ebikes.ca/shop/ebike-parts/controllers/c7225-nc.html

It could also be paired with a cycleanalyst, allowing you to also control max amps, if your motor starts heating up too much, turn amps down.

Note the controller runs sensored and sensorless. Yes, brushless motors can run without the halls, but sensored operation is best.

Click to expand...

I see hub motors that are 24v 350w and some 36v 350w and both turn about 290 rpm. Would it not make sense to get the 24v and put 48v to it and get about double RPM?

Is not the 24v motor rated at 350w heavier duty to handle the higher amperage? What deciding factor makes a motor slower or faster at a given voltage?

Francis

Different number of wraps of the winding gets you a faster rpm, at a given voltage. Less turns (wraps) is faster. so a 6 turn motor is slower than a 4 turn motor.

But again, it sounds like you want speed, so just get a controller that allows experimentation with different voltages. up the voltage till you are going how fast you want to go. 1000w should get you to 30 mph ish. So you don't need huge watts. Just the correct voltage to spin that motor faster. 15 amps at 72v ought to do er.

The motor doesn't care about the voltage. just don't blow out the total watts too much, like 72v 40 amps, would be 3000w. The motor is too small for that!

I suggested a pretty costly setup of controller and cycleanalyst, but whatever motors you choose in the future, that setup has the flexibility to run anything you want, from 200 watts to 1700. And it will be easy to get it to run any brushless motor.

But for now, a cheapo 48v 20 amps controller from ebay, would surely get you more speed than 36v.

Aloha, I am ordering the controller now and cycleanalysis. I assume it is the baseline that I will be able to use with any motor changes, battery voltages that I may go to in the future.

Which model cycleanalysis do you recommend?

Also I will be needing mostly under 5 miles of range, maybe up to 10 miles very rarely, which battery do you recommend? 48v 12ah or 48v 20ah?

thanks
Francis

Aloha. I have a Q100H 36v @260rpm motor now, but I do not see that it will do the RPM needed to get me to 25 mph on a 16" wheel. Even going to 48v I will only get about 17-18 mph. I cannot go larger than 16" wheel.

My current stock setup with the 12" wheel is already going 14mph @ 36v. and must be turning around 400 rpm.

So I assume I need a faster rpm motor right off, what do you recommend?

I see the RisunMotor that claims 420 rpm 36v 750W on ebay here. http://www.ebay.com/itm/RisunMotor-latest-Style-36V-750W-Brushless-Gearless-Hub-Motor-for-Front-Wheel-/161833091315?hash=item25ae0100f3:g:F18AAOSwKIpV~4IC

Is this a good choice?

I am getting the cycleanalysis and the controller you suggested above.

Or what else can I do?

Francis

spdas said:

Aloha. .......
I see the RisunMotor that claims 420 rpm 36v 750W on ebay here. http://www.ebay.com/itm/RisunMotor-latest-Style-36V-750W-Brushless-Gearless-Hub-Motor-for-Front-Wheel-/161833091315?hash=item25ae0100f3:g:F18AAOSwKIpV~4IC........Or what else can I do? ......

Click to expand...

I don't know about RisunMotor.....but,

If you are going to lace up your own wheel with a generic hub motor, maybe get a more powerful motor with a higher RPM. Something like this

http://www.conhismotor.com/ProductShow.asp?id=96

e-beach said:

spdas said:

Aloha. .......
I see the RisunMotor that claims 420 rpm 36v 750W on ebay here. http://www.ebay.com/itm/RisunMotor-latest-Style-36V-750W-Brushless-Gearless-Hub-Motor-for-Front-Wheel-/161833091315?hash=item25ae0100f3:g:F18AAOSwKIpV~4IC........Or what else can I do? ......

Click to expand...

I don't know about RisunMotor.....but,

If you are going to lace up your own wheel with a generic hub motor, maybe get a more powerful motor with a higher RPM. Something like this

http://www.conhismotor.com/ProductShow.asp?id=96

Click to expand...

A question: I do not think I will need 1000w worth of MPH but.......

if I have a 48v 350w going 10mph v.s. a 48v 1000w going 10mph. Will both use the same AH?

thanks
francis

Going the same speed continuously would use the same Ah for either, assuming the same efficiency of the whole system.

But a higher power controller (higher current limit) used with frequent WOT starts from a stop will use more Ah than an otherwise identical system under those conditions.

(though it will get you started and up to speed faster).

amberwolf said:

Going the same speed continuously would use the same Ah for either, assuming the same efficiency of the whole system.

But a higher power controller (higher current limit) used with frequent WOT starts from a stop will use more Ah than an otherwise identical system under those conditions.

(though it will get you started and up to speed faster).

Click to expand...

Thanks, i c, So it is not like an ICE car, One with a 4 cylinder and one with a big V-8 both going 40mph. The v8 will cobble up much more gas @ same speed.

thanks agin.
francis

That's cuz a gas engine is always burning fuel it doesnt' need to, even if you're sitting still.

An electric motor doesn't need to do that.

amberwolf said:

.....But a higher power controller (higher current limit) used with frequent WOT starts from a stop will use more Ah than an otherwise identical system under those conditions. (though it will get you started and up to speed faster).

Click to expand...

Hummm....Is it possable that a 48v 1000w motor could actually end up being a bit more efferent then a 36v 350w motor? If a 36v 350w motor needs to pull maximum amps, say WOT to get moving but a 48v 1000w motor only needs 2/3 of WOT to get moving, couldn't a larger motor actually end up being more efficient?

Leaf bike has a 16in cast hub 48v 1,000watt don't have the rpm.

999zip999 said:

Leaf bike has a 16in cast hub 48v 1,000watt don't have the rpm.

Click to expand...

The Rpm on their chart is 451rpm. One point though, on their chart, the higher amperage that you put into the motor the slower the RPM. Why, seems backward to me??
here is their chart.

http://www.leafbike.com/u_file/images/12_05_02/2a303c0fc4.jpg

francis

spdas said:

999zip999 said:

......The Rpm on their chart is 451rpm. One point though, on their chart, the higher amperage that you put into the motor the slower the RPM. Why, seems backward to me??
here is their chart.
http://www.leafbike.com/u_file/images/12_05_02/2a303c0fc4.jpg
francis

Click to expand...

Click to expand...

Because electric motors are most efficient at high RPM's. Once the motor is turning, it is turning. Once it is turning, on a flat table with no resistance, it needs only the amount of energy required to keep it turning. The energy to get it turning has been spent and used to get it up to speed. Once up to speed the need for energy is reduced to a minimum.

If you hit a hill, or have to stop at a stop light then the energy needed to get it back to speed, or up to speed will be burnt again. But, once you are moving and up to speed again then your energy consumption is again reduced.

Aloha, all.
There is little weight on the driving wheel of my "pod" on my wheelchair and even less as my weight shifts backward under acceleration. Even at the 36v and 350w I have to "feather the throttle" to reduce "burnout". So what will happen when I go to 48v and 1000w?

I am looking at this build here. Can you identify the motor, battery and wheel size? And where is the Controller? (good pix around the 18 second mark).

https://www.youtube.com/watch?v=JfHI_nr92Tg

thanks
Francis

spdas said:

Aloha, all.
There is little weight on the driving wheel of my "pod" on my wheelchair and even less as my weight shifts backward under acceleration. Even at the 36v and 350w I have to "feather the throttle" to reduce "burnout". So what will happen when I go to 48v and 1000w?

Click to expand...

Gotta have as much weight on the front wheel as practicable. Battery packs, electronics, groceries etc, keep it low and in front of the wheel if possible.

I am looking at this build here. Can you identify the motor, battery and wheel size? And where is the Controller? (good pix around the 18 second mark). https://www.youtube.com/watch?v=JfHI_nr92Tg

Click to expand...

I can't tell, but it looks a lot like the Firefly....http://riomobility.com/en/powerhandcycle/firefly-features.html Or maybe something similar.

http://riomobility.com/en/manuals/firefly-usermanual.pdf

Maybe everything is in the battery case. If it is a brushed motor the controller would be small.

Also take note that the video you posted had parts of it "speeded-up" to make this chair look faster around obstacles. Note the "jurky" arm movements from about second 20 to about second 32. The video is clearly speeded-up.

e-beach said:

Hummm....Is it possable that a 48v 1000w motor could actually end up being a bit more efferent then a 36v 350w motor? If a 36v 350w motor needs to pull maximum amps, say WOT to get moving but a 48v 1000w motor only needs 2/3 of WOT to get moving, couldn't a larger motor actually end up being more efficient?

Click to expand...

Sure, it could be possible...but under the state of full WOT for repeated startups from stops the higher current limit system will use more total Ah to do the same trip; my daily commute bears this out with various versions of CrazyBike2, even using the same mtoro and configuration and jsut different controller (like when I had a 6FET on the front 9C vs the later 12FET on it). It's more obvious with shrot trips with many stops/starts, but it still shows up on longer trips with fewer stops.

spdas said:

Even at the 36v and 350w I have to "feather the throttle" to reduce "burnout". So what will happen when I go to 48v and 1000w?

Click to expand...

Under those conditions, you won't be able to use all that power, then--if you can never WOT with the existing system, you'll have to do even less throttle for the higher power. (assuming same torque at the same speed points).

If there are conditions that allow you to use WOT with the old system, then you would also be able to do at least that much with the new one, possibly more, you'd have to test that out.


Best is to do as noted by e-beach, to put all teh weigth you can forward of teh powered wheel to ensure it gets mroe traction.

Normally when a wheelchair gets a handbike there would be a second axle mounted so the wheelchair wheels can be mounted rearwards. That way more weight will be placed over the front handbike tire. See pictures of my manual handbike and wheelchair with the dual axle set up (green circled axle is the front axle for normal wheelchair riding):






If you have the possibility to mount an extra rearward axle be advised that the instability in corners will increase further. When riding at a reasonable speed hang into corners when steering. Otherwise you'll tip over (ask me how I know... ).

After sleeping on it I had a thought. A fast wind (6T or 7T) 48v 1000w in a 16 inch wheel. With lower torque then a conventional wheelchair motor it would not spin-out as much upon start-up, but will still have the power when necessary to power up a hill. Combined with a long lasting low C chemistry like LiFePO4, it could do the trick.

Combined with a Cycle Analyst, the CA could be set to 2/3 or 3/4 power to mitigate any spin-out if desired.

Just a thought.....