Rider less cycle conversion kit required.

[BootstrapBob]

I know this might seam like an odd request and at the moment is quite hypothetical but please bear with me.
I require an electric motor and control unit to power a three wheeled trolley up an incline carrying no more than 50kg total weight.

My calculations show the motor needs to be no more than 250W and capable of delivering a torque of around 25Nm, dependant on the incline and pull speed. The trolley has 16" wheels with the rear wheel being the powered one and hence my reason for asking on here for recomendations.
Because the operator will be at the top of the slope, he/she will control the trolley via a cord which will act like a dog leash attached to a sprung return throttle lever. The operator will pull the cord but will not in theory be taking the full weight of trolley, the motor will be assisting the pull in the same way a pedal assisted cycle would work as you apply pressure to the pedals.

Whatever is used does not need a display unit, a PAS could be used and attached to the wheel so that the throttle only works when the trolley starts to move but the key thing is to have the variable speed lever so that the operator has full control of speed. Batteries need to be from a reputable manufacturer and reliable.

There are loads of options available out there but I am hoping the experience on here will be able to narrow down a few options for me.
Cost is subjective, there is a budget but I would like to see what is available before commiting.

I look forward to hearing some suggestions.

 

[matthewslack]

Clean, dry tarmac / concrete surface, or off road/ muddy/not smooth etc?

16" overall wheel and tyre diameter, or 16" bicycle rim?

Private land, private project? Or land with public access, work context?

 

[BootstrapBob]

I knew I would miss something.

Tarmac/concrete
16" rim (think Brompton).
Private project.

 

[saneagle]

I know this might seam like an odd request and at the moment is quite hypothetical but please bear with me.
I require an electric motor and control unit to power a three wheeled trolley up an incline carrying no more than 50kg total weight.

My calculations show the motor needs to be no more than 250W and capable of delivering a torque of around 25Nm, dependant on the incline and pull speed. The trolley has 16" wheels with the rear wheel being the powered one and hence my reason for asking on here for recomendations.
Because the operator will be at the top of the slope, he/she will control the trolley via a cord which will act like a dog leash attached to a sprung return throttle lever. The operator will pull the cord but will not in theory be taking the full weight of trolley, the motor will be assisting the pull in the same way a pedal assisted cycle would work as you apply pressure to the pedals.

Whatever is used does not need a display unit, a PAS could be used and attached to the wheel so that the throttle only works when the trolley starts to move but the key thing is to have the variable speed lever so that the operator has full control of speed. Batteries need to be from a reputable manufacturer and reliable.

There are loads of options available out there but I am hoping the experience on here will be able to narrow down a few options for me.
Cost is subjective, there is a budget but I would like to see what is available before commiting.

I look forward to hearing some suggestions.

You should buy the parts individually from Aliexpress. You need to think about the motor's maximum RPM. You need it to spin at about 1.3 times it's modal speed for good efficiency. RPM choices are fairly limited, so the better way is to mount the motor separate to the wheel, fit a sprocket to the disc brake fixings and use it to drive a sprocket on the axle.

There are durable kits, like this one:

48V 800W Electric Bike Brushless Motor Conversion Kit Electric Tricycle Scooter DIY Motor Controller Handlebar Throtte Refitment - AliExpress 18

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

And cheap ones like this with brushed motors:

High-Speed Electric Motor Controller Kit For Scooters 24V250W 250W 300W 400W Motor Control Unit For Electric Vehicles

Smarter Shopping, Better Living! Aliexpress.com

vi.aliexpress.com

Whatever motor you use, you might want to think about one that can work in reverse, which means no freewheel or one way clutch in it. There are controllers that have a pair of wires for a reverse switch too.

If you calculated that you need 250w, you should use a battery, controller and motor that can handle around 600 to 800w to deal with the lack of efficiency at anything other than its design modal speed. The acceleration from start requires a lot of power. Any motor has zero efficiency at zero speed and very low efficiency near to zero speed.

All throttles provide a signal in the range 1v to 4v for the controller, so you can use any device that provides signals in that range - either fixed or variable. The signal is a speed control one, not power control. The controller has its own algorithms for power in response to the speed signal.

Choose 48v for efficiency.

Let us know how you get on or anything else you need

 

[thelarkbox]

Sounds like a static/top mounted motor pulling a cart/sled with a winch might be better/cheaper??

A KT controller needs no pas and has throttle input enabled out of the box and can be run headless for circa £30-40

If not aiming to run a bldc at/close to optimum rpm it can get complicated with extra heat and determinin a duty cycle.

there are wheelbarrow e-motor kits that might fit the bill?

 

[matthewslack]

Private project and land means you can do what you like. A lot of considerations if work use.

The safest arrangement is something which has a fundamental restriction to its maximum speed, and which cannot roll if power is turned off.

Simplest is obviously just a Brompton motor wheel, which is a 16" front wheel with a hub motor. But does not satisfy the requirements of inherently safe.

To consider would be the Bafang wheelbarrow motor.

Suppose you use a standard ebike motor. You can minimise speed by choosing the lowest rpm motor, typically a 201rpm nominal at 36V, and intended for a 700c rim. But in a 16" rim the nominal maximum speed would still be around 9mph, so at sensible speeds for your project, not operating in it's comfort zone. But it would work.

Edit: Operate at 24V and max speed drops to 6mph, but torque lower too.

If you paired such a motor wheel with the usually loathed cheap type of controller, i.e. 'speed control' type, and use the lowest, slowest setting, you might have a solution. You would need to spoof the PAS input, to make it think you are pedalling, but that's easy, a simple pulse generator switched on and off by by your remote operator to start and stop the device. You also need speed sensor, but that is usually included in the motor wheel.

If you only need fixed speed simplicity, that is just about a solution.

Amy add-ons that you don't need such as display just fit if needed to make it work and ignore them.

You can use the brake sensor inputs for an emergency stop button, although that will not put brakes on.

 

[Scorpio]

If you explain what the project is for you might get some more tailored suggestions :
What are you moving?
How far from the bottom of the incline to the top?
What about steering?
How will you get it back down the hill?
Use an electric wheelchair / mobility scooter as a base for the project?
Use remote control for the up/down left/right controls to save dragging a control wire behind the unit (how will you make sure you don't drive over the wire??)

A fixed winch at the top of the hill isn't very interesting but could be a neat simple solution.

 

[BootstrapBob]

You should buy the parts individually from Aliexpress. You need to think about the motor's maximum RPM. You need it to spin at about 1.3 times it's modal speed for good efficiency. RPM choices are fairly limited, so the better way is to mount the motor separate to the wheel, fit a sprocket to the disc brake fixings and use it to drive a sprocket on the axle.

Whatever motor you use, you might want to think about one that can work in reverse, which means no freewheel or one way clutch in it. There are controllers that have a pair of wires for a reverse switch too.

If you calculated that you need 250w, you should use a battery, controller and motor that can handle around 600 to 800w to deal with the lack of efficiency at anything other than its design modal speed. The acceleration from start requires a lot of power. Any motor has zero efficiency at zero speed and very low efficiency near to zero speed.

All throttles provide a signal in the range 1v to 4v for the controller, so you can use any device that provides signals in that range - either fixed or variable. The signal is a speed control one, not power control. The controller has its own algorithms for power in response to the speed signal.

Choose 48v for efficiency.

Let us know how you get on or anything else you need

Thanks Saneagle, that's all good information.
I was thinking about a seperate motor and chain originally and will take another look. I do still like the idea of a hub motor for simplicity.
Throttle signals in the 1-4v range makes sense, I had guessed it was some kind of rotary potentiometer and didn't actually limit motor voltage directly, the at would have to be rather a beefy potentiometer.

 

[BootstrapBob]

Sounds like a static/top mounted motor pulling a cart/sled with a winch might be better/cheaper??

A KT controller needs no pas and has throttle input enabled out of the box and can be run headless for circa £30-40

If not aiming to run a bldc at/close to optimum rpm it can get complicated with extra heat and determinin a duty cycle.

there are wheelbarrow e-motor kits that might fit the bill?

A static winch would be the better solution I agree if the trolley was to stay in one location however it may get moved to other locations.
I had to google bldc but good to know.
I will look at wheelbarrow motors.

 

[BootstrapBob]

If you explain what the project is for you might get some more tailored suggestions :
What are you moving?
How far from the bottom of the incline to the top?
What about steering?
How will you get it back down the hill?
Use an electric wheelchair / mobility scooter as a base for the project?
Use remote control for the up/down left/right controls to save dragging a control wire behind the unit (how will you make sure you don't drive over the wire??)

A fixed winch at the top of the hill isn't very interesting but could be a neat simple solution.

Thanks Scorpio
Electric wheelchair / mobility scooter is a good suggestion.
The application is more of a garden trolley to be used by the elderly around a slopping garden on paths.
Steering and release braking are already taken care of I was just curious about motive power alternatives by using a pull cord and throttle lever.

 

[BootstrapBob]

Private project and land means you can do what you like. A lot of considerations if work use.

The safest arrangement is something which has a fundamental restriction to its maximum speed, and which cannot roll if power is turned off.

Simplest is obviously just a Brompton motor wheel, which is a 16" front wheel with a hub motor. But does not satisfy the requirements of inherently safe.

To consider would be the Bafang wheelbarrow motor.

Suppose you use a standard ebike motor. You can minimise speed by choosing the lowest rpm motor, typically a 201rpm nominal at 36V, and intended for a 700c rim. But in a 16" rim the nominal maximum speed would still be around 9mph, so at sensible speeds for your project, not operating in it's comfort zone. But it would work.

Edit: Operate at 24V and max speed drops to 6mph, but torque lower too.

If you paired such a motor wheel with the usually loathed cheap type of controller, i.e. 'speed control' type, and use the lowest, slowest setting, you might have a solution. You would need to spoof the PAS input, to make it think you are pedalling, but that's easy, a simple pulse generator switched on and off by by your remote operator to start and stop the device. You also need speed sensor, but that is usually included in the motor wheel.

If you only need fixed speed simplicity, that is just about a solution.

Amy add-ons that you don't need such as display just fit if needed to make it work and ignore them.

You can use the brake sensor inputs for an emergency stop button, although that will not put brakes on.

Thanks Matthew,
Again good information to know.
The minimum speed is I think an important one to consider and may be pushing me back towards the motor-chain drive option suggested by Saneagle.

 

[saneagle]

Throttle signals in the 1-4v range makes sense, I had guessed it was some kind of rotary potentiometer and didn't actually limit motor voltage directly, the at would have to be rather a beefy potentiometer.

Nearly all motor controllers have microprocessors in them that do stuff on the bases of input signals. The throttle is an analogue input in the range 0v to 5v. The throttles normally have a hall sensor in them that gives a signal 1v to 4v. There's logic in the controller that can sometimes detect anomalous signals, so it throws an error if outside that range, and they have safety algorithms that will prevent operation if the throttle signal is above say 0.5v when you switch on.

In most cases, you can use a potentiometor to give the speed signal as long as you remember to set it to zero before you start, or you can make a simple on/off max speed switch by shorting the signal wire to the 5v, though, rarely, some controllers detect 5v as an error. In that case you can use a potentiometer in a fixed position with a switch, or a simple voltage divider with two resistors (1k and 5k) .

 

[thelarkbox]

Lots of mobile winch base options from a simple anchor plank you stand on or stake down to professional ladder hoists used to carry bricks/cement up ladders for builders.

If the slopes are too much for the result of adding a stand plate and rear wheels to a wheelbarrow and applying an e-wheelbarrow motor i would urge you back to winch consideration too.

 

[lenny]

 

[harrys]

I'd go with RC control. A long wired throttle cable is going to get fouled up.

 

[BootstrapBob]

Thanks for all your suggestions folks.
I ran the ideas past the person this was aimed at last weekend and lets just say they were less than enthusiastic about the idea.
Ah well, it seamed like a good idea but at least I can now get on with my own pedelec project.