E-bike gurus please step in, building a wheelchairiot thing

[skyking]

Originally Posted by rumdog

Batec Mobility - Add-on handbikes for wheelchair: manual and power handbikes easy to attach to the wheelchair. Revolutionary anchoring system - Batec Mobility - Handbikes acoplables para silla de ruedas: acoples para silla de ruedas, propulsores para
For once a year this would be overkill, but my buddy has one of these.... actually thats him on the lake pulling his kids. He uses a studded tire in the winter. May help with the creative juices!

sand is the hard part.

Yes it is. That is why I was thinking a pair of rear drives on 26" fat wheels, and some larger and wide front casters. I can fab all that up in aluminium to keep weight down.
I think the batec would spin out trying to drag conventional wheels through anything dicey.

[Frank Lee]

Originally Posted by California98Civic

Consider direct drive motors rather than geared, because when throttled-off the direct drive will acf as a brake, which is good for a wheel chair.

The hubmotor on my Songi has zero braking action unless the regen circuit is activated. I'd think the geared motors would have the power-off braking action.

[redneck]

Originally Posted by Frank Lee

Ha, I have one of those.




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[skyking]

Originally Posted by redneck

Ha, I have one of those.




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Love the necker's knob

[Frank Lee]

Originally Posted by redneck

Ha, I have one of those.




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How easy is the steering? And traction, stability, etc.

[Grant-53]

Torque on a motor is a function of current and speed is a function of voltage. Dynamic braking comes from connecting the armature leads to one another with no power applied. I like the ATV tires and chain drive.

[redneck]

Frank Lee

How easy is the steering? And traction, stability, etc.

Steering effort is moderate, suicide knob helps. Poor traction on soft ground and not very stable are probably the reasons it never caught on.



Something like this would be best. Although it doesn't meet your non transfer needs and is expensive,

TracFab - All Terrain Tracked Wheelchair



A electric wheel chair with the wheel base stretched out and widened would work.

Harbor freight has cheap castors with air tires. Mini ATV wheels could be used to replace the drive wheels on the donor electric wheelchair to provide more traction.






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[skyking]

Things are percolating now. Initially I had him rolling into it from the back. Now I see that is not as good as backing into it.
I could find a donor one of these, they break all the time I am sure something could be had.
Pride Jazzy 614 HD Heavy Duty/High Weight Capacity Power Wheelchair - Pride Heavy Duty/High Weight Capacity Power Wheelchairs
Mount better wheels at the drive motors, install them on my frame. Make my own front big casters. Re-use the power chair controller and battery system. Big wheels will give it some decent go.

[California98Civic]

Originally Posted by Frank Lee

The hubmotor on my Songi has zero braking action unless the regen circuit is activated. I'd think the geared motors would have the power-off braking action.

Maybe it depends a on the manufacturer, but the direct drive motors I inquired about put constant drag on the wheel. The geared motors are the ones that free wheel. That's why regen is not available with the geared bike motors and is with the direct drive motors.

[gumby79]

How about a Cyistalite
G-30
Specks :

The G motor design for light weight and the rear wheel cassette free hub
It is with special outlet to make it different with other.
　
Motor power : 250 to 350 watt
Motor speed : 25km/hr , 30km/hr and 40km/hr
Motor weight : 3.8kg rear wheel and front wheel
　
Axle dropout :
Front motor dropout :
- 75mm dropout for 16" and 20" folding bike.
- 100mm dropout for front wheel /24" to 28" wheel bike
Rear motor dropout :
- 135mm for 8 speed or 9 speed cassette
　
Spokes for motor : G13
Number of spokes holes : 36pcs
　
Disc brake :　
Front wheel and rear wheel available for install disc brake,
Normal 6" and 8 " disc brake available.

I've run a crystalite 503 3kw @72vdc on
The hub drive motor was re spoked with DOT motorcycle rim. This was way to fast for your app. 45-50mph sustained @1500w load it yealded 157wh/mi and 50mi+ range on a 20ah 72v bat
The reason for a geared hub is ,no drag from the windings while pedaling.
My regen/ebraking was a fixed value,on or off, ming was set to 800w with a push button, and would cut out @~5 mph
the G-30 is specked at 15mph with a 26"bike tires @24v and accepts standerd bike disk brakes.
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Sensored or sensorless?
Sensored no cogging more failure points.
Sensorless cogging,simpler construction , cheeper controllers.
motor will start moving to figure out which way it is moving, switch back and forth between forward and reverse to figure out which way it's supposed to be going. Normaly 1/2" or less. Cogging is normaly on take off only and gone by .25-.5mph.