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Ebike motor controller

Tonymura

Jul 25, 2021
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Hi guys

How are we all doing. Long time no hear or even here!

Hope we all had a good Christmas

Just wanting some simple advice as i am in the process of building a ebike to play around with as i have a few permanent dc magnets motors laying around in which i want to put to some good use and i am attaching one of them to the rim of my wheel on my mountain bike.

My question here is is as this is not a big project i have printed out a few brackets including a thumb throttle for my bike handles but my choice of a speed controller has left me slightly confused and thought it might be best to ask the forum here as if i think i have chosen something that might be suitable for my bike...well i think it will suit my ebike but i cant be to sure.

I have the circuit diagram to show you all.

This is what i have

Please correct me if you believe this isn’t suited for my application and if you have anything better in mind...I’m all ears.

Thank you in advance.
 

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Alec_t

Jul 7, 2015
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Brushed or brushless motors? Brushless with internal commutation may not play nicely with external PWM.
You probably want a FET with lower Rdson resistance than IRF540, to handle high motor currents.
 

bertus

Moderator
Nov 8, 2019
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Hello,

Keep the voltage on the 555 between 12 and 15 Volts, to have a high enough voltage to drive the mosfet.
Also choose a diode accros the motor that has a current capability the same or higher as the motor current.

Bertus
 

Tonymura

Jul 25, 2021
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Brushed or brushless motors? Brushless with internal commutation may not play nicely with external PWM.
You probably want a FET with lower Rdson resistance than IRF540, to handle high motor currents.

Thank you for the reply
My motor current would draw at maximum i would be, i say 3 to 5 amps at most.
If this is the case the 10 volts rdson seems to be very high should the battery fall below the minimum threshold this would not be such a favarable device to have in the real practical world. In your opinion can you please recommend a better Mosfet to use in this design OR can you suggest a better motor controller for me to use altogether.
 

Alec_t

Jul 7, 2015
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would be, i say 3 to 5 amps at most.
Is that the normal running current or the stall current? The latter might be ~ ten times the running current of a brushed motor.
can you suggest a better motor controller for me to use altogether.
Depends on motor type, which you haven't specified.
What motor supply voltage will you use?
Are you aware of the legal requirements for e-bikes in your country?
 
Last edited:

Tonymura

Jul 25, 2021
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Is that the normal running current or the stall current? The latter might be ~ ten times the running current of a brushed motor.

Depends on motor type, which you haven't specified.
What motor supply voltage will you use?


The motor can handle up to 33 volts but i am planning at most between 24 to 28 volts as the supply.

It has a tremendous amount of torque even at voltages as low as 2 volts I can not seem to stop the shaft from turning even if I try holding it with my hand.

My power supply on my bench top is showing me a current reading of 1.5 amps @ around 3 volts and the shaft is still turning even if I attempt to simulate a load so it would be an excellent motor to use.

All I can say about this motor is that it was salvaged out of a ink jet conveyor that is no longer now used and if i recall the power supply board on the conveyor was running at most about 1.2 to 3 amps and the main board had a 5 amp fuse that would seldom blow unless the main conveyor belt would become jammed up.

The motor brand name is tagged as Pitney Bowes, that is... it was manufactured by a large Mailing Equipment supplier that produced specialised machinery. We had to purchase spares from the US and the last time we got one shipped to us we paid about $180 USD and that was about 10 years ago. The manufactures are somewhere in Philadelphia and we had it shipped to Australia
 

WHONOES

May 20, 2017
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You should hunt out a Logic level Fet. They are designed to be fully enhanced at a lower voltage e.g. an IRL530 is fully enhanced at 7V. This is only an example and not a recommendation.
 

Tonymura

Jul 25, 2021
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Is that the normal running current or the stall current? The latter might be ~ ten times the running current of a brushed motor.

Depends on motor type, which you haven't specified.
What motor supply voltage will you use?
Are you aware of the legal requirements for e-bikes in your country?

I would like to use 24 volts using Lipo battery and i hope by the end of today i can load my bike up and spin the back wheels that is simulate temporary a load by applying the hand brake on for a few minutes to see what current it will draw in the real world.

I will post the results after i have manufactured the drive wheel for the motor.

in regards to the legal requirements well...it should be ok as just about everyone here down under in the land of Oz uses a ebike without anyone issues i plan to ride my bike on a bike path occasionally now and then just for a bit of fun.
 

Tonymura

Jul 25, 2021
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Is that the normal running current or the stall current?
Hi
We have done a live test run and it is at 2 amps running with no load and with a slight load the stall current was at 2.6 amp
However it appears i will need to add a reduction gear box as i loose the torque.
I will need to make up a roller and put it on the motor shaft as the wheel was measured at 180 rpm but this speed will be much more less when i reduce it.
 

Bluejets

Oct 5, 2014
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in regards to the legal requirements well...it should be ok as just about everyone here down under in the land of Oz uses a ebike without anyone issues i plan to ride my bike on a bike path occasionally now and then just for a bit of fun.

Sorry to burst your bubble BUT there are many rules and regulations that must be followed.
These cover where, when, how, power etc.etc.
Depending on which state you are currently in, (as usual) different for every state or territory.
Usual advice, check out what is and what isn't allowed to stay on the right side of the law and not end up another road statistic.
Flippant " she'll be right mate" went out the window many years ago.

WA example here....... https://www.wa.gov.au/organisation/...MI-c_wgYyI9QIVV5JmAh0DQQRFEAAYASAAEgLaePD_BwE
 

Tonymura

Jul 25, 2021
30
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Sorry to burst your bubble BUT there are many rules and regulations that must be followed.
These cover where, when, how, power etc.etc.
Depending on which state you are currently in, (as usual) different for every state or territory.
Usual advice, check out what is and what isn't allowed to stay on the right side of the law and not end up another road statistic.
Flippant " she'll be right mate" went out the window many years ago.

WA example here....... https://www.wa.gov.au/organisation/...MI-c_wgYyI9QIVV5JmAh0DQQRFEAAYASAAEgLaePD_BwE

Hi thank you for your concerns

I just checked it out the rules and regualtions of the ebike for NSW and this is what it says.

What are the e-bike requirements?

There are two types of permitted e-bikes:

  • Power-assisted pedal cycles
  • Electrically power-assisted cycles.
These must be designed to be propelled primarily by the rider – they cannot be propelled exclusively by the motor. The motor is intended to help the rider, such as when going uphill or riding into a headwind.

Power-assisted pedal cycles
A power-assisted pedal cycle:

  • Has one or more motors attached with a combined maximum power output of 200 watts
  • Cannot be propelled exclusively by the motor/s
  • Weighs less than 50 kg (including batteries)
  • Has a height-adjustable seat.
Electrically power-assisted cycles
An electrically power-assisted cycle has a maximum continued rated power of 250 watts. This power output must be:

  • Progressively reduced as the bicycle’s speed increases beyond 6km/h
  • Cut off when:
    • The bicycle reaches a speed of 25km/h; or
    • The rider stops pedalling and the travel speed exceeds
https://roadsafety.transport.nsw.gov.au/stayingsafe/bicycle-riders/petrol-powered-bicycles.html

Mainly those petrol type attachments that you can buy off ebay and add them to your bike are not allowed on the roads
 

Bluejets

Oct 5, 2014
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Hi thank you for your concerns

I just checked it out the rules and regualtions of the ebike for NSW and this is what it says.

What are the e-bike requirements?

There are two types of permitted e-bikes:

  • Power-assisted pedal cycles
  • Electrically power-assisted cycles.
These must be designed to be propelled primarily by the rider – they cannot be propelled exclusively by the motor. The motor is intended to help the rider, such as when going uphill or riding into a headwind.

Power-assisted pedal cycles
A power-assisted pedal cycle:

  • Has one or more motors attached with a combined maximum power output of 200 watts
  • Cannot be propelled exclusively by the motor/s
  • Weighs less than 50 kg (including batteries)
  • Has a height-adjustable seat.
Electrically power-assisted cycles
An electrically power-assisted cycle has a maximum continued rated power of 250 watts. This power output must be:

  • Progressively reduced as the bicycle’s speed increases beyond 6km/h
  • Cut off when:
    • The bicycle reaches a speed of 25km/h; or
    • The rider stops pedalling and the travel speed exceeds
https://roadsafety.transport.nsw.gov.au/stayingsafe/bicycle-riders/petrol-powered-bicycles.html

Mainly those petrol type attachments that you can buy off ebay and add them to your bike are not allowed on the roads


10 points for taking the time to look it up.
Well done.
Most wouldn't give a toss.
 

Tonymura

Jul 25, 2021
30
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Jul 25, 2021
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Any other markings on its name-plate? Amps, Watts, HP, ...? Does it have brushes?
Its not visable
Its faded away on one of the motor the other two motors have no name plates
It has brushes with a permanent magnet.
 

Alec_t

Jul 7, 2015
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For a DIY build, something based on the circuit in your first post should work for a brushed motor, but it would probably be simpler and cheaper just to buy a suitably rated brushed motor controller from an online source. I'd go for one rated at >30A
 

Tonymura

Jul 25, 2021
30
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Jul 25, 2021
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For a DIY build, something based on the circuit in your first post should work for a brushed motor, but it would probably be simpler and cheaper just to buy a suitably rated brushed motor controller from an online source. I'd go for one rated at >30A

Part of the enjoyment of doing this yourself is that you make it on your own.

This circuit does not have much components and the only item i will change is the Mosfet as suggested to me by Whonoes above

If i was going to purchase one already pre made then i would not have posted this topic here for help.

The circuit i took was from the internet, i posted it here for advice if it would be suited for what i was doing and if it would be a good controller to build.

I got a lot of responses from the community here and i greatly appreciate on what was said but i would have preferred MORE...! that is...if someone would have said to me...hey....use this Other circuit its much more better than the one you just posted......( thats what i was hoping for ) such was not the case, you were the closest in telling me to buy one already made up, anyhow that’s your opinion and you been honest with me....having said its not a very important topic as i am going to build it anyway because i have all the components at hand and there is not that many parts on the circuit board. So It should be fun. This is the only circuit i have atm in mind so ill just go ahead and build it..

I appreciate everyones comments here.

Thank you
 
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