Understanding Your E-Bike Electric System: A Complete Guide

Understanding Your E-Bike Electric System: A Complete Guide

E-Bike owners love the impressive power and speed of their rides. Features like strong motors, dependable batteries, and powerful pedal assist let riders go farther and faster than ever before. 

With so many important functions to perform, the quality of an e-bike’s electric system can make or break your riding experience. Let’s take a look at the components of the system, what they do for your ride, and how they interact with each other to form a complete system.

Looking for a specific system component? Skip ahead:

Why Is A Quality E-Bike Electric System Important?

It isn’t just quality parts like batteries and motors that are critical for e-bike performance. Powerful e-bike electric systems need quality connections, too. So if you want high-powered rides with fewer maintenance headaches, it’s critical to understand what you’re getting before you buy. 

Magnum electric systems are built from scratch with the big picture in mind. We use top-notch components and intelligent engineering to maximize the power and quality of your ride. What does that mean?

Each component in the system is designed to work in sync with the rest. For example, Magnum controllers are custom-programmed to work with each bike’s unique motor and pedal assist system (PAS). Because of that, every model offers a distinct riding experience — meaning there’s a Magnum Bike for every type of rider.

On the other hand, with e-bikes skyrocketing in popularity, many new brands want a piece of the action without spending the time and money necessary for a great electric system. Cheaply constructed e-bike motors compromise on performance and spend more time in the repair shop.

By investing in an e-bike with a quality electric system, you’re actually likely to save money and time overall! How? Better performance coupled with reduced need for maintenance and a longer lifespan. Combined, these benefits save you time and money on maintenance, repairs, and frequent replacement.

The E-Bike Electric System: Explained

An e-bike’s electric system is so much more than its battery and motor! Understanding each piece of the system, its function, and how it works within the system is critical to making the right feature decisions when you purchase. Let’s take a look at all the components of an e-bike’s electric system and how they each contribute to performance.

See All Your Settings With The Display

E-Bike displays give riders a look at their settings, battery health, speed, and range. Advanced displays may have unique features like illumination in low light conditions or the ability to sync to your phone via Bluetooth. There’s no universal standard for displays, so design varies between manufacturers and models. That said, they’re usually mounted somewhere on the handlebars for easy viewing and access while riding.

Features Of A High-Quality Motor

The motor’s main job is to convert electrical energy into mechanical energy. The motor receives the electrical current provided by the battery and uses it to physically turn the shafts, producing the torque needed to get the bike rolling. 

Torque is the rotational force produced by the components turning inside the motor. More powerful torque allows the electrical system to handle tough conditions under strain, including steep slopes, loose sand, or sticky mud. 

Top-tier motors produce enough torque to make climbing steep hills a breeze.  Torque also helps bikes pull heavy loads — a feature that our Magnum E-Bike cargo model riders especially love. 

Magnum outfits e-bikes with top-tier motors from Bafang and Maxis. This collaboration has been essential to the quality of our e-bikes — so much so that the motors they produce for us are now branded as Magnum Bikes motors. 

All Magnum E-Bike motors are high-quality brushless DC motors (sometimes abbreviated as BLDC). What does that mean? 

Brush motors use physical brushes to change the flow of current. But over time, worn-down brushes lower the motor’s efficiency. 

Instead of brushes, Magnum brushless motors use permanent electromagnets. Since the components of this motor don’t actually touch each other, nothing physically wears down. That means the motor maintains its powerful performance over a longer lifespan compared to a brush motor.

Because your battery and motor work closely together, utilizing batteries and motors with compatible power outputs increases efficiency, prolonging the lifespan of your e-bike.

All About E-Bike Batteries

E-Bike batteries need to store enough electricity to power your motor throughout your ride. A high-quality battery makes the difference between a long-lasting, powerful ride and a ride cut short. 

When it comes to power and capacity, batteries are categorized by their voltage, amp-hours, and watt-hours. 

Voltage (V)

Power. Voltage measures the electrical output. Higher voltage = more power. Common voltages for e-bike batteries are 36V and 48V. 

Amp-Hours (Ah)

Capacity. Amp-hours describe how much electricity the battery can store. More amp-hours = larger capacity, resulting in a riding experience with longer range.

Watt-Hours (Wh)

Voltage x Amp-Hours. Watt-hours show the total amount of energy used over time, calculated by multiplying voltage by amp-hours. For example, a 36V 20Ah battery has 720Wh (36*20 = 720).  

Most e-bike batteries have between 300 and 800 watt-hours. The more watt-hours your battery has, the longer and/or harder you can ride.

Across manufacturers and models, e-bike batteries come in all shapes and sizes. Some e-bikes feature removable batteries mounted to the downtube or rear rack; to charge these batteries, you remove them from your bike. Other bikes integrate the battery neatly into the downtube, creating a more aerodynamic profile. Fully fixed, integrated batteries cannot be removed, so your bike needs to be stored somewhere that you can charge it regularly.

Whether integrated or not, today’s e-bike batteries are lighter, longer-lasting, and more reliable than ever. That’s thanks to modern lithium-ion technology, leaving clunky and inefficient lead-acid and nickel-cadmium batteries behind.

Selecting Different Speeds With Throttles And Pedal Assist Systems

When it comes to controlling speed, many modern e-bikes use a pedal assist system instead of or in addition to a throttle. Pedal assist helps preserve the feel of a “natural” unassisted ride because you still need to pedal to move ahead; you just get a little more power behind each pedal stroke. Conversely, throttle-only e-bikes act sort of like a motorcycle, strictly in the sense that the bike can move forward without any pedaling required.

Class 1 is limited to 20mph with pedal assist and the bike must not have a throttle. Class 2 is limited to 20mph with pedal assist and the bike has a throttle. Class 3 is limited to 28mph and the bike has a throttle. If the bike has only a throttle it will likely be classified as a motorized vehicle.

Let’s examine the two more closely.


Riders engage the throttle to determine how much power they want. Sensors then determine how much of the throttle is engaged, from off position to full-throttle.

The two most common throttle designs for e-bikes are paddle and twist throttles. You can engage a paddle throttle by pressing it with your thumb. To use a twist throttle, twist part of the handlebar grip backward.

Pedal Assist System (PAS)

As the name suggests, pedal assist systems only give an extra push when the rider is actively pedaling. When you stop pedaling, the motor disengages. This requires smart technology and sensors to recognize when a rider is on the pedals so that the bike doesn’t engage without a rider on board.

PAS sensors come installed on the e-bike’s crankset: the part that connects the pedals to the bottom bracket. When pedaling, the cranks are moving too, which tells the system when you’re ready for an extra push.

Higher-end bikes with PAS also include a torque sensor that measures how hard the rider is pedaling. At the start of a ride, the torque sensor is responsible for giving you a smooth boost to begin pedaling, instead of a sudden jolt of power. Bikes without a torque sensor take a little longer to engage the pedal assist, and the acceleration isn’t as smooth. 

All Magnum e-bikes feature six levels of pedal assist, compared to the industry average of just two or three levels. These extra options give riders a truly custom experience with the right amount of pedal assist for any terrain. Just be aware that riding in the higher pedal assist modes will drain your battery faster.

To view and change modes on your pedal assist system, you’ll usually find buttons on the handlebars along with a small display or set of LED lights indiciating your current setting. Depending on the bike, users can customize pedal assist levels between rides. Some models even have an off-bike mode that can help you push your heavy e-bike up a ramp or stairs.

The Controller: Key To The Entire System

The controller is the processor that responds to a rider’s throttle and PAS controls, bringing the motor and battery functions together. This small device manages how much battery power is being delivered to the motor at any given time, ranging from 0 volts to that battery’s maximum. 

A controller performs best when its voltage range is paired to the electric system’s specific motor. When a low-current controller is paired with a large motor, it can’t send enough electricity to reach the motor’s maximum power output. On the other hand, connecting a high-amperage controller to a small motor can damage the motor. Controllers in a cheap electric system are subject to any of these flaws.

Ride Farther With The Right E-Bike Electric System

E-Bike electrical systems are intricate and highly nuanced. It’s difficult to understand all of the components and how they all come together to create your perfect ride. We hope this guide has helped owners to understand their e-bikes better. And for would-be riders shopping for their first e-bike, hopefully you’ve gained some perspective on the features and specs that are most important to you. 

If you have questions about your e-bike’s electrical system, check out your manual or manufacturer’s website. And if you’re a Magnum owner or want to be one, please get in touch with us! We’d love to talk through any questions you have about our motors, PAS, and more.