E-Bike Brain: Decoding Controllers and Software

E-bikes have transformed personal transport, with the best electric bike options allowing people to ride further far easier than ever. Even for regular bikers it has opened up new opportunities, allowing them to climb steeper slopes, go faster and train harder.

Today, there are so many new models to choose from, whether you are looking for a simple E-bike to get to work on, or a mountain E-bike for conquering nature, you can look at dozens of different models. But while ebike reviews can help, they don’t always highlight the importance of the heart of any E-bike, the controller and software that drives it all.

There are a number of options out there, but what do they really do, and how much do they impact your riding experience? Today we are going to take a look at ebike controllers to get a better understanding of why they are so important.

E-Bike Controllers

The Brain of E-Bikes: The Controller

The Brain of E-Bikes: The Controller 

While they come in different forms, every electric bike for adults or children has a controller that makes everything work as you expect it to. The controller is essentially a computer dedicated to one task, running the bike. That means deciding how much power the motor provides to help you, maintaining battery condition and so on. The pedal-assist sensors, the throttle, battery and motor itself all link to the controller, and for the best electric bike models, it is this controller and its software that make all the difference.

The software within the controllers is calibrated for each bike to optimize performance and monitor a range of actions including:

  • Temperature – Monitor the electrics and motor, shutting down power if it detects overheating.

  • Current Protection – Can cut power if excess current is drawn as this can damage the motor.

  • Voltage Regulation – Monitors and controls voltage to prevent both too high or low voltage to protect both battery and motor.

  • Peddle Assist – How much power the system provides to help you peddle.

  • Brake system – Sensors show how much brake is being applied and shits down the motor so it isn’t forcing you forward as you try to slow down.

  • Screen – The controller powers the screen providing all the essential information you need.

There are two main types of motor controllers today, Brushed and Brushless. While some very basic bikes still used brushed motor controllers, the majority on the market now, and certainly all of the best electric bike options, use a brushless electric motor controller.

Sine or Square Wave?

In addition, controllers offer a couple of ways of controlling motor output. Sine wave controllers are the more expensive option, but provide better efficiency, especially under load, such as when climbing. They also allow the motor to run more quietly than the cheaper, square wave controllers too, and are smoother in operation. However, sine wave controllers not only cost more than square wave alternatives, but they also consume more power and need to be matched to a specific motor type.

By contrast, the cheaper square wave options offer a less precise power management on the throttle and tend to run at higher voltages, with steps in the power delivery that cause ‘jumps’ in progress sometimes. However, they work with any motor, and while can use less power, are not as good as sine wave under heavy load. You can find the best electric bike for adults with either option, depending on use. For an electric mountain bike, where climbing and heavy load is common, sine wave makes more sense, but commuter bikes are more about consistent but lighter loads, and here the best electric bike may have a square wave controller.

To summarize:

Sine Wave Controller:

  • Great under load such as climbing
  • Less Noise during operation
  • Smoother power delivery
  • Consumers more power
  • Needs to be matched with a motor
  • More expensive

Square Wave Controller:

  • Cheaper
  • Works with a range of different motors
  • Better efficiency for lighter loads
  • Louder noise
  • Can have power spikes that causes jumps in acceleration
  • Poor efficiency under heavy loads

If you are looking for a new controller for your best ebike, or scanning ebike reviews, think about how you use your bike to see which type would be the preferred option for you.

Hall Sensors

If you have a bike with a motor equipped with hall sensors, it needs a controller designed for them. Hall sensors use magnetic fields, rather than any sort of mechanical or electrical resistance, to identify the rotation of the motor, and require a controller and software designed to interpret those inputs correctly.

A hall sensor offers a smoother, more precise read of the motor speed and so on, and uses much less voltage than other sensor types too, so there are significant advantages, and the best electric bikes usually have hall sensor motors fitted.

Fitment to the bike

controller of happyrun ebike

Placing the controller under the seat is a wise choice

The final thing to think about with controllers is how they fit the bike. With an electric bike for adults there are a few options. Some mount directly to the battery, others are houses in a control box fitted to the bike, often seen on bikes with a battery that is located within the bike frame, normally the downtube. Finally, there are the mid-drive controllers, that are integrated into the motor itself.

They all work the same, and which is right for you will depend on the bike. However, mid-drive controllers can be awkward, as a service means dismantling the motor to some extent as well, so if you are looking for the best electric bike for long term use, avoiding those can be a sensible choice.


Its something we take for granted and ebike reviews tend to ignore mostly, but a good controller is essential if you want to find the best electric bike for your needs. If you have a bike and are thinking of changing controllers, then remember to look at how and where you ride, as well as how your current controller fits to the bike.

For people who do a lot of climbing and other heavy load applications, then a sine wave controller in a suitable fitment is ideal. If you are more about acceleration and light loads on your commute, a square wave option may be just what you are looking for.

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