Throttle vs potentiometer question

[KirstinS]

Strictly this is an electric scooter question but applies to Ebikes to (old brushed motor ones anyway )

So my dad has a very old electric 24v brushed motor scooter (500w) he uses it with his boat for zipping around marinas

The controller went and he bought a new one.(without speaking with me first !)

He bought this

12V 24V 20A Max PWM DC Motor Stepless Adjustable Speed Controller 25kHz

Only US$15.99, buy best 12V 24V 20A Max PWM DC Motor Stepless Adjustable Speed Controller 25kHz sale online store at wholesale price.

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It has a pot not a throttle as clearly for another dc motor use. He then bought a standard thumb throttle but it doesn’t work (on any wiring)

At this point he came to me. I think the issue is the pot has a switch incorporated where a throttle doesn’t

Most throttles I find with switches seem to be for main power on/off only and are separate to the throttle signal

I do realise the pot does 0 to 5v but a throttle prob does .5 to 4.2v signal which may well affect top speed

Any ideas ? Thanks vm

 

[danielrlee]

It might be that the controller is waiting for a 0V pot input before it will initialise.

 

[Deleted member 25121]

Are you able to control the motor using a pot?

 

[vfr400]

Switch on the controller, then disconnect and reconnect the throttle to see what happens. If it works afterwards, then the controller needs 0V to initialise.

Next, with the controller switched on, measure the voltage between the red and black wires on the pot to confirm that it's 5v.

Finally, connect the throttle and measure the voltage on the orange wire to confirm that it's giving the correct signal.

If the pot does have a switch in it, it won't have any function other than to disable the pot for safety reasons.

 

[KirstinS]

It might be that the controller is waiting for a 0V pot input before it will initialise.

Possibly, in which case is there anything I can do to fool the controller ?

 

[KirstinS]

Are you able to control the motor using a pot?

Yes, it works perfectly

 

[KirstinS]

Switch on the controller, then disconnect and reconnect the throttle to see what happens. If it works afterwards, then the controller needs 0V to initialise.

Next, with the controller switched on, measure the voltage between the red and black wires on the pot to confirm that it's 5v.

Finally, connect the throttle and measure the voltage on the orange wire to confirm that it's giving the correct signal.

If the pot does have a switch in it, it won't have any function other than to disable the pot for safety reasons.

Thing is there is no separate on switch , just the pot itself ?

 

[vfr400]

Switch on or connect power is the same thing.

 

[danielrlee]

Possibly, in which case is there anything I can do to fool the controller ?

You might be able to fool the controller by switching the output on a hall-effect throttle. Switch off the signal wire before the controller is initiated (when power is connected). Once the controller is on, switch the signal wire back on. Be careful though because the minimum signal of a hall-effect throttle will output ~1v and this will cause the motor to run all the time.

The bigger problem is that there is no way to convert the 1-4v throttle signal to 0-5v without the use of a microcontroller. I'd ditch the controller and purchase another one intended for use with a hall-effect throttle.

 

[Deleted member 25121]

Yes, it works perfectly

You could look at incorporating the pot into a throttle, probably rather difficult, or modifying the throttle switch so that it emulates the pot at either extreme ie provides 0V or +5V. Do you know what's inside the throttle right now?

 

[KirstinS]

Thanks all

Deccided to just buy the correct controller and throttle . A full 15qyid delivered

All help much appreciated

 

[SKF]

Hi,

Could you point me in the direction of the controller and throttle that you got in the end. I have a project where I am using a bafang mid drive to control a kinetic sculpture.

 

[lenny]

I am using a bafang mid drive to control a kinetic sculpture.

Do you have a photo and is your kinetic sculpture road going?