How Does an Electric Bike Work: Comprehensive Guide to E-Bikes

Exploring the intricacies of electric bikes, this article delves into how these innovative machines function and revolutionize modern cycling.

Electric bikes, or e-bikes, are revolutionizing the world of cycling, offering riders a boost of power to make their journey smoother and less strenuous. At the heart of an e-bike is its motor, battery, and controller, all of which work together to assist the cyclist.

When you pedal, the motor gets activated by either a sensor detecting pedaling motion or by the force you apply to the pedals. The motor then uses power from the battery to provide assistance, making it easier to tackle hills or long distances. The controller lets you choose how much help you want from the motor.

Read on to delve deeper into the mechanics of these ingenious machines and understand how each component contributes to your e-biking experience.

Key takeaways:

  • Electric bikes assist with pedaling for a smoother ride
  • Components include battery, sensor, and motor
  • Battery voltage affects speed and range
  • Torque and cadence sensors control motor assistance
  • Motor types include hub, mid-drive, and friction drive

What Is an Electric Bike?

how does an electric bike work

An electric bike, often referred to as an e-bike, is basically a bicycle but with the addition of an electric motor to assist with the pedaling. E-bikes use rechargeable batteries that can help to power the cyclist for distances of 25 to 45 kilometers at speeds up to 25 kilometers per hour.

Point worth noting is that an e-bike is not designed to take complete control but to assist pedaling, helping you overcome hilly terrains or long distances with relative ease.

They play an integral part in modern urban mobility, offering an eco-friendly alternative to vehicles, while also promoting physical activity.

Understanding the Components of an Electric Bike

Three main components influence the performance and characteristics of an electric bike: the battery, the sensor, and the motor.

1. The battery acts as the power source for the system. Usually 36v or 48v, it provides the energy necessary to drive the motor. It’s essential to note that the higher the watt-hours (Wh) of the battery, the longer the range.

2. The sensor plays a critical role in measuring either how hard the rider is pedaling (torque sensor) or simply that they are pedaling (cadence sensor), to determine how much assistance to provide.

3. The motor turns the electrical energy from the battery into mechanical energy, propelling the bicycle forward. It may be placed at the front wheel, rear wheel, or near the pedals (mid-drive). The location of the motor can significantly impact the bike’s handling and overall riding experience.

The Battery

Taking center stage in an e-bike’s function, the battery serves as the power source. Two main types typically found in these machines are Lithium-ion and lead-acid batteries. A preference for Lithium-ion is commonly noticeable due to their lightweight build and long life cycle.

Batteries can come in various voltages, typically ranging from 24V to 48V. It’s crucial to consider the distance and speed you intend to achieve, as a higher voltage will provide more power, enabling a higher speed and a longer range.

The placement of the battery potentially affects the bike’s balance. Some models have it fitted in the rear, while others prefer a central location for optimal weight distribution.

Batteries are charged by plugging the bike into a standard wall outlet; with most requiring between 3 to 6 hours for a full charge. The length of time a charge lasts depends substantially on factors such as the bike’s speed, rider’s weight, and terrain.

The Sensor

There exist two primary types of sensors in electric bikes: torque sensors and cadence sensors.

The latter detects pedal movement, thus when you start pedaling, the motor engages and when you stop pedaling, the motor disengages. This corresponds to a basic on/off function, and doesn’t necessarily account for the variation in pedaling speed.

On the other hand, torque sensors capture the force you apply to the pedals. The greater the force applied, the more powerful the motor response. This brings about a natural and intuitive e-biking experience, as the bicycle responds to the specific force exerted.

For a more refined and responsive ride, numerous e-bikes incorporate both sensor types. Iso remember to check which sensor your bike uses, as it greatly affects your cycling experience.

How Electric Bike Motors Work

Placed typically in the hub of either wheel or at times, the center of the bike frame, the electric bike motor is a compact yet powerful component that propels the bicycle forward. There are basically three types of motors associated with e-bikes: Hub motors, Mid-Drive motors, and Friction Drive motors, each with unique features.

Hub motors are encased in the wheels, offering a smooth and reliable ride. They can be located in the front or rear wheel and work by rotating the wheel where they’re housed.

Mid-Drive motors, positioned near the pedals, are directly connected to the bike’s drivetrain. This placement offers better balance and more efficiency on steep inclines, working synergistically with the bike’s gears, a factor that can affect the riding experience.

Friction Drive motors, less common, work by running a roller against the bicycle’s wheels. This operation creates friction that propels the bike forward.

Tucking in pedal-assist or riding full electric, the bike motor is designed to amplify the power created by the rider’s pedaling, delivering an extra boost and resulting in a more effortless and enjoyable ride. The electric motor functions in such a way that it stays inactive while you pedal at your desired speed, smoothly kicking in when you need that additional push.

Electric Bike Wattage Explained

Wattage distinguishes, in simple terms, how much power a motor can deliver. It’s a combination of the voltage supplied by the battery and current (amps) that flows to the motor. Generally, the larger the wattage, the more powerful the e-bike will be.

Electric bikes are usually rated between 200 and 750 watts. High-wattage bikes are more equipped for steep inclines and heavy riders. The lower wattage models, on the other hand, are perfect for flat surfaces and lighter loads.

However, the wattage figures are not the only determinant of an e-bike’s performance as it’s also dependent on other factors like motor efficiency and battery capacity. Therefore, while selecting an e-bike, considering the combined impact of these factors is necessary.

The Impact of Voltage On an Electric Bike’s Operation

Voltage determines the power delivered from the battery to the electric motor. Higher voltage corresponds to greater power output, which can lead to faster speeds.

For instance, a 36-volt battery paired with a powerful motor will result in higher speed than the same motor matched with a 24-volt battery. Conversely, the amount of power a lower-volt battery can deliver may be insufficient for a motor designed for higher voltage, causing inefficiency and lower performance.

It’s crucial to pair your e-bike’s motor with a battery of suitable voltage. This not only optimises speed and performance, but it can also extend the lifespan of your e-bike’s components, preventing unnecessary strain or damage.

Remember, while higher voltage can increase speed, it does not inherently mean longer range. That’s determined by the battery’s capacity, typically measured in amp-hours.

Electric Bike Amp-Hours Explained

Amp-hours, often abbreviated as Ah, is a unit of electric charge that quantifies the capacity of a battery. In simpler terms, it’s the ‘fuel tank’ of an e-bike. For an improved range and longer usage, a higher Amp-hour is beneficial.

A smaller 5Ah battery might seem less capable, but remember, its performance also depends on the system’s voltage and how power-hungry the bike’s components are. The range you can get from a 5Ah battery could vary greatly between a low-powered 250W e-bike and a high-powered 1000W model.

The ideal scenario is to have a high Amp-hour (Ah) together with a high voltage to achieve peak performance and maximum range. However, this may add to the weight of the e-bike. Always strive to balance your battery selection based on your bike weight, riding style, and terrain.

Regular recharging and maintaining your e-bike’s battery can prolong its life, translating to more miles on the road. Avoid complete discharges and always store in a cool, dry place to prolong your battery’s lifespan.


Do you still have to pedal an electric bike?

While some electric bikes have a throttle feature enabling usage without pedaling, others necessitate pedaling for engaging the battery and motor.

Do electric bikes charge when you pedal?

While some models do provide the functionality, most electric bikes do not charge when you pedal and require their batteries to be plugged into a power outlet for effective charging.

Is it harder to pedal an electric bike?

The difficulty of pedaling an electric bike varies depending on its design, with some models similar to regular bicycles, some more challenging due to features like battery regeneration, and others nearly impossible to pedal over significant distances.

What is the average range of an electric bike on a single charge?

The average range of an electric bike on a single charge is approximately 40-50 miles, depending on the terrain, the rider's weight, and the bike's battery capacity.

How does the motor assist function on an electric bike increase rider efficiency?

The motor assist function on an electric bike increases rider efficiency by supplementing the rider's pedal power with additional propulsion, thereby reducing physical exertion and enhancing speed.

What types of terrain are electric bikes best suited for?

Electric bikes are best suited for various terrains including paved roads, gravel paths, and moderately steep inclines, thanks to their added motor power.