Intro to Electric Bikes - What They Are & How They Work

What are electric bicycles?

When someone hears electric bicycle, the first image they imagine may be a scooter or electric motorcycle - but they actually look pretty different. Just picture a regular bicycle, then add several electrical components to it like a motor, a battery, and a controller – all seamlessly integrated into the design. These items make up the fundamentals of all electric bicycles on the market!

How electric bikes work

Electric bikes pedal and handle just like a regular bicycle. By and large, an electric bike will use the same parts too. The electric component is meant to augment human power, not completely replace it. It makes obstacles like hills and headwind more manageable and allows you to travel further without getting as tired.

See our diagram for a more detailed look at how electric bikes work including the motor, battery, drivetrain, and charging process:

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Choosing the right electric bike

Comfort and quality of the components are still as important on an electric bike as they are on a regular bicycle. But now, there are a few more things you need to consider.

The motor

Electric bike motors come in a wide variety of power ratings, from 200W to 1,000W or more. The legal limit in the US is 750W, although different states can set their own limits.

Think of this limit kind of like horsepower. A higher rating means that the bike will be able to pull more weight with greater ease – but at the expense of using more battery capacity while doing so. Consequently, a 750W motor will drain the battery much quicker than a 250W one, but it will be more powerful.

One more factor needs to be considered, however. The design and location of the motor plays an important role in how electric bikes work.

The most common type of motor for electric bikes is called a hub motor. It is generally integrated into the rear or front wheel. When engaged, it pulls or pushes the wheel along. Although this system works well, it has one key disadvantage. Since it is not connected to the bike’s gears, it loses efficiency on hills and varied terrain. Imagine driving a vehicle in just one gear the entire day. It will get you places, but it won’t give you the optimum amount of torque or speed that you get with a full gear range.

At EVELO, we offer a patented mid-drive motor, which is integrated with the crank and the gears. This adds several advantages:

  • Increased performance while spending less battery energy, since the mid-drive motor uses the bike’s existing gears;
  • Much better hill climbing power, since you can switch gears depending on the incline; and
  • Handling is improved, since the motor is positioned closer to the ground, keeping the weight centered and low.

The battery

Since the battery affects the weight, style, and range of the bike, its choice is crucial. Batteries play a huge part in how electric bikes work. The majority of the batteries you’ll find offered on the market fall into one of the following two categories:

Sealed Lead Acid (SLA)

These batteries were once the standard battery type for most electric scooters and electric bicycles. These days, most electric scooters still use SLA batteries, while electric bikes (which often require human input) have opted for newer battery technologies to keep the bike as lightweight as possible.

  • Inexpensive
  • Heavy and bulky
  • Offer a shorter riding range
  • Shorter life span of about 100-300 full cycle charges
  • Require more maintenance, and need to be charged immediately after use

Lithium (Ion/Polymer/Manganese/Etc.)

These are the newest technology in batteries. A lithium battery has a lifetime roughly 2-3 times that of an SLA battery. Lithium batteries are much lighter and also are largely maintenance-free.

  • Lightweight – high-capacity, 36V10Ah Lithium-Polymer batteries can weigh as little as 6 pounds!
  • Offer a longer riding range – battery can travel up to 40 miles in pedal-assist mode (or 20 miles on throttle-only).
  • Longer life span of about 800 charges or 3 years of virtually daily use
  • More expensive – starting at about $1,500 to $3,000 and above

The controller

Available in a variety of styles, the controller lets you operate the electric assistance on your electric bike and is an important part in how electric bikes work. The controller is located on the handlebar for ease of use. There are two main styles of controllers – pedal-activated and throttle-based controllers.

Pedal-activated systems offer electric assistance as you press down on the pedals. There is no need to engage a throttle – simple pedaling will do the trick. Electric bikes with pedal-activated systems have a controller mounted on the handlebar that lets you adjust the level of assistance that you receive as you pedal. You can dial in the amount of assistance you want, ranging from no assistance to a great deal of assistance.

Throttle-based controllers work with a simple throttle mechanism. The throttle will either be a twist-grip type or a thumb-press type. With a throttle, you simply pull back or press the throttle to receive the electric assistance. Some electric bikes require nothing more than activating the throttle, allowing you to ride without pedaling.

By and large, electric bikes are simple to use, ride, and maintain. Overall, they require little maintenance beyond that which a standard bike requires.

How do I operate the bike?

Electric bicycles are designed to be very easy to operate. As a rider, you have three modes of operation available to you:

Pedal Only

At any time, you can pedal an electric bicycle just as you would with a regular one. There is no extra resistance created by the motor, so it will feel exactly as a regular bicycle would. Depending on the model you purchase, your bicycle will come either with a 3 gears or 8 gears or a special NuVinci® N360™ internal drivetrain that provides you with unlimited gears.

Pedal-Assist (sometimes called Electric-Assist)

In this mode, you can take advantage of combined human plus electric power. Once you turn on this mode via the on/off button on the handlebars, the motor will gently provide electric power as you pedal. You can still switch gears as the terrain changes to take advantage of more torque or faster speed. It’s an amazing feeling to use pedal-assist mode, as it makes cycling effortless, flattens out the hills, and frees you to just enjoy yourself and the scenery.

Pedal-assist mode provides three levels of assistance: Low (30%), Medium (60%) and High (100%). The percentage simply indicates how much additional power the motor will provide to complement your pedaling. The low setting adds an additional 30% of power to your pedaling, while High essentially doubles it. A simple press of a button switches you through the different levels.


This mode of operation allows you to sit back and take a break, as you let the motor do the work. To use “electric only” mode, simply twist the throttle located on the left handlebar and you’ll feel the motor kick in and propel you forward. Keep the throttle turned to continue along or let go if you’re ready to start pedaling or wish to come to a stop. Please note that due to Federal regulations, the top speed in electric-only mode is limited to 20 miles per hour.

Do I need a license to ride one?

Electric bikes are still a fairly new concept in the US, so there is a lot of confusion about how the law views them. Federal law considers electric bicycles in the class as regular bicycles, provided they meet two conditions: (1) the top speed in “electric only” mode is 20 miles per hour; and (2) the motor power must be no more than 750W.

EVELO electric bicycles meet both of the federal requirements. We cap the top speed in “electric only” mode at 20 miles per hour, although you can of course go faster on your bike with pedal power if you wish. Our motors are rated at 250W, which is well within federal limits.

Consequently, electric bikes do not need a special registration, license, or insurance to operate. Moreover, they enjoy the same privileges as regular bicycles, such as being allowed to travel in available bike lanes.

However, different states have their own special requirements regarding electric bike use. While most follow the federal lead, some do vary. If you have questions about how electric bikes work in your state, you can get in touch with us and we’ll point you in the direction to find out additional information for your state. For your own personal safety, we recommend helmet use and lights and reflecting gear, even if the law does not specifically require them.