What Is An Ebike Controller? Find Out Here!

Last Updated on October 13 2022 by Sam

Our Ultimate Guide To E-Bike Controllers


The e-bike controller is one of the most important parts of an electric bike, responsible for all the components of the bike working together, you could call it the brain or heart of your electric bike. 

An electric bike controller takes all the essential info from the motor, PAS, battery, and throttle and relays its signal to the other electric parts of the bike. This controller is connected to the LCD on a bike too so it can show the collected information.

We've put together a short guide below which will cover how these controllers work, where they should be, the types and how to connect them. 

How Does An Electric Bike Controller Work?

Before we can discuss the different kinds of controllers and how to connect them, let's get familiar with how this electronic heart of the e-bike works. 

An e-bike controller is typically located in a controller box, most types of controllers take the battery current energy and direct it to the motor, changing the throttle on a bike allows you to change and manipulate this power in levels of assistance. 

Where Should The Electric Bike Controller Be? 

Typically you will find that most advanced controllers on e-bikes are located next to the battery, but some can be in a battery bag or a controller box, you can also just mount them directly to the frames.

They should be located near to the battery power however for the wires to be able to reach.

What Types Of Electric Bike Controllers Are There? 

If you're new to learning about e-bike controllers, you might not realise that there are different types such as brushless and brushed controllers. 

We've listed the three main type of controllers below. 

Brushed DC Motor Controllers 

These type of controllers are most common, they are great to use for DIY e-bike kits and are even found on scooters thanks to their simple design. They have magnets to go with the connector and keys can control the controller current with ease.

Brushless DC Motor Controllers 

Brushless controllers are for use with higher efficiency brushless motors, the controller is also very simple and comes with three phases which can be controlled by keys too. 

BLDC Controller Hall Sensor

These type of controllers are electronically driven by the motor in an electric bike and have no brushes to move their rotor, the rotor is instead moved and controlled by the hall sensor. This is connected to the stator which is still part of the motor and determines speed.

What To Consider When Choosing An E-Bike Controller

Choosing an e-bike controller can be confusing if your converting your standard bike into an electric one, we've listed a few essentials to check and look out for below. 

  • Power and voltage - If you are selecting a non-programmable controller design then you must ensure that the voltage matches the motor with the controller and the power is slightly more. For a programmable controller, the power can be changed but the voltage should still match the motor and battery power.
  • Current rating - The current rating of your controller should be less than the output current of the battery on your e-bike, most tend to be between 25A and 40A.
  • Driving type - E-bike controllers have two different kinds of waveforms, a sinusoidal waveform and a rectangle waveform. If you choose a sine wave controller you can expect them to be more predictable and smooth, they are also better for uphill control when riding, rectangle forms on the other hand are lower priced and can be used with different kinds of motors. They are however much noisier.
  • Phase and battery current - The phase current is joined to the motor and can be higher than the battery current. Ensure that the phase current and motor current is matched otherwise the bike could overheat.
  • Hall sensor - If the electric bike motor has a hall sensor then the controller needs to have one too, this allows the motor to have a lower power consumption while maintaining its torque.

Frequently Asked Questions About E-bike Controllers 

How long will a cheap controller last? 

An average controller lasts around 5 years on an electric bike, a cheap controller might last you about three before it starts to get issues such as overheating.

Is there a way to test a controller current?

You can use a multimeter to test the controller by seeing if there is a resistance of MOSFETs, set the meter to continuum mode then the probes to the negative line of the battery and test each line, a peep would mean it is short. 

To use an e-bike tester for this job you would need to remove the controller, take off the throttle then turn the tester on as well as the throttle and see if the tester lights blink to show its functioning.

Can I rest my e-bike controller modifications?

Yes, to rest your electric bike controller you can typically find an option in the settings with a Y, you could alternatively disconnect the controller by the wires and rewire it back in.

How much does a quality controller cost?

E-bike controllers are not costly and typically cost around the $50 mark or below depending on the brand.

What does an e-bike LCD show?

The LCD connected to a controller shows the level of pedal assistance, battery level, and distance, some controller display models also have additional features such as a GPS and mobile connection.

Can you change the controller on an electric bike?

Most electric bikes can be upgraded to different controllers without any issues as long as it still matches your motor power, this could be to draw more power from the battery, for example, you would need to disconnect all the wires from the previous controller to install the new ones so professional help might be needed.

Last Words

To conclude, an e-bike controller is the brain of an electric bike, translating and relaying signals to all electrical components, it's responsible for moving power to the motor too and controlling assistance modes. 

Always ensure you are choosing a matching controller for your motor if doing an e-bike conversion to prevent problems such as overheating, make sure the controller has the right driving type too and a hall sensor if your motor has one.

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