Why Don't More E-Bikes Use Regenerative Braking?

Electric bikes (e-bikes) have revolutionized the way we commuted and bicycled. They offer the convenience of quick transportation while simultaneously being eco-friendly.

However, as with all motorized transportation, there is the need to consume energy stored in the battery. This is where regenerative braking comes in, to reduce the energy consumed by the e-bike and extend its range.

In this blog post, we'll explore what regenerative braking entails, how it works for different types of e-bikes, its advantages, and potential issues.

How Regenerative Braking Works for Different Types of E-Bikes:

Regenerative braking works by converting the bike's kinetic energy into electricity. This energy is then stored back in the bike's battery for later use. Below are the different ways regenerative braking works for the various e-bike types:

Direct Drive Hub Motors: Direct drive hub motors don't involve any additional mechanical parts to work. When you pedal backward or use the brakes, the motor turns into a generator, and the generated current is stored in the battery. This driving process is also highly efficient, as the motor's direction changes quickly, preventing energy loss.

Geared Hub Motors: Geared hub motors are more popular in e-bikes than direct drive hub motors due to their smaller size, lightness, and increased efficiency.

They function similarly to direct drive hub motors, but as opposed to utilizing magnetic resistance, they use brakes to lock the front wheel, enabling the regeneration of energy. 

Mid-Drives: Mid-drives are becoming increasingly common in E-bikes. Regenerative braking works similarly to the geared hub motors, whereby energy is regenerated by braking when the motor is engaged in pedaling.

In a makeshift setup, they have the chain and chainring connected directly to the motor, which would allow for regenerative brakes.

Advantages of Regenerative Braking:

Regenerative braking has several advantages, including:

Cost: Regenerative braking systems are cost-effective and relatively uncomplicated to install. And since it can extend the bike's battery life, you won't need to purchase a new one soon.

Range Improvement: Regenerative braking can extend your e-bike's range by up to 40% on downhill sections. It's also great for urban riding, where there's often a stop-and-go, making it an ideal investment for city dwellers.

An electrostatic brake (as used for regenerative braking) does not wear out as brake pads do.

For longer rides or frequent downhills, this is a benefit since bike brake pads, while cheap, don't have that much material on them and can be a hassle to swap frequently.

Potential Issues with Regenerative Braking:

Despite the advantages of regenerative braking, there are a few downsides to it. Potential issues identified are:

Overcharging the battery: The regenerated energy needs to be controlled to prevent overcharging, which can damage the battery.

Limited range improvement: Regenerative braking is only effective when you're cycling downhill, making it less useful during flat or uphill riding.

Energy Generation: Try not to go into regenerative braking expecting the same amount of resources generated as you would with electric cars.

Electric cars output around 50 times the amount of kinetic energy that an electric bike does, so it's only natural that the amount of energy restored is just as many times greater.

Compatibility issues with non-regenerative systems: Regenerative braking is not compatible with all e-bikes. It's, therefore, essential always to check the compatibility and available options before investing.

Conclusion

Regenerative braking undoubtedly serves as an excellent investment for anyone who wants to improve their e-bike's range while simultaneously reducing costs.

It proves easy to install, cost-effective, and primarily advantageous for those who commute in cities or go through a lot of downhill riding. However, we recommend that you check the compatibility of your e-bike before investing.

If your ebike's motor is equipped with a compatible motor, what you need to do is look for a controller capable of providing you with regenerative braking, and the best part is those controllers only cost around $20.

Worst case scenario, your bike is equipped with electrostatic brakes, which are proven to be more effective overall. They're far more durable and last longer than a regular set of brakes.

With regenerative braking, cycling becomes more practical, and you can still stay eco-friendly while doing so.

References:

Sources used for the Blog Post: 

3. "How Does Regenerative Braking Work", by energy.gov.

1. Stojanović, T. (2015). Effectiveness of electrical regenerative braking of electric bicycles and e-motorcycles. Therm Science, 19(3), 761-766.

2. Nørregaard, J., & Ravn, P. (2016). Optimization of a regenerative braking system for an electric bicycle. IET Electric Power Applications, 10(5), 343-352.

3. Yin, Z., Wu, Q., Li, H., & Sanfeliu, A. (2016). An experimental study of regenerative braking operation of an electric bicycle. Energies, 9(7), 522.