7 Questions People Always Ask About E-bike Controller

7 Questions People Always Ask About E-bike Controller-Haidong ebike

E-bikes have a few electrical components and need something to regulate their function. An e-bike controller serves as a connection between the various electrical components. It helps the rider comfortably navigate the route. It performs critical functions like starting, stopping, and changing the speed of an e-bike. Here we have a compilation of the seven questions people always ask about e-bike controllers.

1. What is an e-bike controller, and what does it do?

E-bike Controller

It is a small device that consists of main chips called the microcontrollers and the peripheral components that include resistors, various types of sensors, and MOSFET (metal-oxide-semiconductor field-effect transistor). The chips contain quite a few circuits for the smooth functioning of the e-bike, including the Pulse Width Modulation (PWM) circuit and power circuit.


An e-bike controller connects to every electrical component such as the battery, motor, sensors, display screen (if present), throttle, and pedal assistance. It manages how the various electrical components work for a safe and smooth ride.

As you press the throttle, the controller draws energy from the battery via the motor, consequently managing the bike’s speed. It is a kind of mini-computer that receives inputs from various parts of the e-bike like the throttle, battery, motor, speed sensor and responds with an output or response. Examples of such a response include some stats or control options on the display screen or the increase or decrease of speed.

The e-bike controller monitors bike health via sensors and performs safety functions.

Protection Monitor Action
Low-voltage Battery voltage dropping too low Shuts down the motor to protect against over-discharge
Over-voltage Battery overcharge Shuts down the battery
Over-temperature Rise in Field-effective Transistors (FET) temperature Shuts down the motor, protecting the motor and FET transistors
Over-current High flow of current to the motor Reduces the current flow, protecting the motor and FET transistors
Brake Protection Braking action takes precedence over other commands If you signal acceleration and brake at the same time, the brake takes effect

7 Questions People Always Ask About E-bike Controller-Haidong ebike

2. What are the different types of e-bike controllers?

Brushless DC Motor Controllers

These are three-phase controllers. A set of keys and a minimum of two transistors control each phase. As the name indicates, these controllers manage e-bikes with BLDC motors. These are the most commonly found motors on e-bikes, thanks to their reliability and efficiency.  

Brushed DC Motor Controllers

These are relatively simple controllers. A set of keys regulate the amount of current supplied to the motor. These controllers work with the BDC motors. The BDC controllers are found in smaller electrical vehicles and favored by those interested in DIY projects.

BLDC Motor Controllers for Hall Sensor

Hall sensors monitor the rotor (moving part of the motor) location about the stator (fixed) based on the Hall Effect. The relative position helps the controller determine when and where to push the rotor to change speed or identify the voltage requirements. Once the sensors direct the input signal to the controller, it responds by providing the required voltage to the motor.

3. What are square wave and sine wave controllers?

Sine wave and square wave are the two types of controller drivers and get their names for the phase voltage waveform each shows.




Square Wave

Smooth performance

Cost more


Offer better control

Work with matching motors only


Less noisy

Consume more power


Better performance at a lower speed


More suited for uphill rides or carrying weight

Since Wave

Offer more torque during acceleration



Suitable for more motors

Less smooth torque



Lesser efficiency at regular speed

And if you are wondering which one you should go for, it all depends on your needs. Figure out what you are going to use the bike for, and you have your answer.

4. Can I modify a controller? If so, should I?

It is something you are likely to pick up from DIY enthusiasts and bloggers. You can find both programmable and regular e-bike controllers in the market. The programmable ones allow you to adjust the settings like power and speed limits, the level of assistance you want, and other options.

The regular controllers may not ideally be for tweaking. Yet, it does not stop some garage creatives from making the changes. They can adjust to get more current (amperes) to get more speed and acceleration or more voltage to get a more comfortable ride and increased average performance.

It would not be too good an idea to make such changes. They are designed for specific purposes, and pushing them may result in overheating, and in extreme cases, they may blow up. However, what you can do is make a direct purchase from e-bike manufacturers. Some of those support controller customizations and are likely to give you a product that is not risky to use.

7 Questions People Always Ask About E-bike Controller-Haidong ebike

5. How much does an e-bike controller cost?

The price of a controller varies depending on the functions it can perform. At the lower end, you can find it within the range of $20 – $60. It will have some basic bike assistance options and limited features. The higher-end controllers can cost anywhere between $200 – $500. The pricey ones offer more features, and they can handle more motor power. The programmable e-bike controllers with adjustment options are usually on the higher price end.

6. When should I change an e-bike controller? Is it ok to repair the previous one?

Like all other parts, e-bike controllers wear out over time. On average, if you take good care of your bike, keep it charged, clean, protect it from weather extremes, the battery, motor, and controller will last three to four years. Once you notice signs of wear and tear in a controller, such as flashes of light or strange sounds, check it for health. You can either do it yourself or take it to an expert mechanic. If it does show signs of damage, you should get a new controller.

People with the right expertise can repair a controller, depending on how damaged it is. If the damage is too much, it would be unwise to spend your time and effort to fix it, instead of buying a new one. Also, devices have a lifetime, don’t push them beyond that, or you may risk your vehicle’s health and your safety.

7. How to find out which controller I should get?

Consult seasoned e-bike riders, repair shop owners. Make sure you speak to people who have the expertise to judge which of the options available in the market are worth your investment.

Do your research about the type of controller you need. Match the requirements on your original controller or as shown on the bike’s manual and search for the ones closely matching the description. See what other buyers have to say about the controller you are searching for; is it good quality, or does it need repairs often?

Buy the motor and controller kit instead of individually sourcing the latter. It will take away the hassle of matching the controller specs with the motor. It is helpful for novices without any prior experience or knowledge.

If buying the kit is not an option, make sure you match the controller and battery current. Phase current is the device’s output current and may be higher than the current it receives. Look to match the phase current of the two devices.

It is best to source your parts from the original e-bike manufacturer. Contact them and ask if they provide spare parts and consult their expertise for an update.


A controller is the brain of an e-bike. It monitors the performance and tells it what to do. Brushless DC motor controllers are most popular among the manufacturers for their higher efficiency. Both sine wave and square wave controllers have their pros and cons. Users have to understand their needs before they decide which suits them. For those seeking a controller modification, consult a manufacturer instead of causing damage to your device. It is better to buy a motor and controller kit, especially if you are a newbie. It will avoid disappointments and possible disasters.

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