Variable speed limiter. Now I can limit the speed of the e-bike.

Speed limiter

I recently modified my e-bike controller to work sensorless up to 100 volts. I am currently using a 20S lithium battery and I can reach over 50 kph. On a bicycle it’s a lot!

Video of the bike:


I wanted to limit the speed in some way, I actually have a 3-speed switch supplied with my controller but it does not work properly, the speed is limited somewhat electronically “chocking” the motor and it feels awful when riding.

So I decided to use a potentiometer to regulate the maximum speed of the bike. The limit can be set at any time, even while the bike is running.

The advantages of setting the maximum speed on the bike are several: increase the range, limit the power in case you are in very crowded areas (the throttle can be very aggressive at full power/speed), limit the power in case the bike is used by someone else, etc..

Potentiometer back

This mod is accomplished limiting the maximum output voltage going to the controller.

I connected the potentiometer this way:



10 thoughts on “Variable speed limiter. Now I can limit the speed of the e-bike.

  1. Hi Jacopo, good idea simple and useful, maybe you can even evaluate the opportunity to use Arduino to set the “economy mode” by using a potentiometer that can be changed via sw.

    • Thank you Ccriss,
      I had an idea about limiting the speed when the battery gets close to LVC so you can return safely home or go to a recharge point at limited speed without damaging your battery.
      I don’t like the fact that the bms “cut” the power if the pack voltage is under lvc..pedalling an electric bicycle is ok when you have no power, pushing a 100kg scooter is not so ok..I’ve done it :-/

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  3. Great idea. You think the same can be done to limit the pas? I have a speed limiter on the controller for the throttle, but the pas is to powerful. Making it useless when riding with family.

    • No.This mod has nothing to do with that. If you apply this mod the top speed of your e-bike will stay the same, but you can set a lower speed limit so you use less energy from the battery for example. The top speed limit is normally set by the voltage of the battery and the controller.

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