Getting the most out of your E-bike battery

E-bikes and trikes are huge right now! And for good reason - they allow more riders to get out and enjoy the outdoors, exercise and remember that first glimpse of freedom cycling gave them many years ago. Unfortunately, as many of us have aged or suffered from trauma/injury/illness, riding a bike isn’t as easy as it used to be. Electric assist is the solution!

As people are coming in to our shop, day in and day out, asking about electric assist, what is the most common question? “How far will an e-bike go” is right there at the top. The easy answer is “it depends on the terrain and what level of assist you are using”, but let’s delve a little deeper.

There are a variety of ways to determine how efficient your e-bike/trike battery and motor system will be:

The easiest part of this equation to understand is the battery size. The number of cells in the battery determine it’s Ah measurement. For example, you can have a 14Ah battery or a 17Ah battery.  This will be listed under the battery specs.

The other important number is the wattage of the system. Most systems range from 36W to 48W. The higher the wattage, the more efficient the system - you will see why in a moment.

The total amount of energy you have for your e-bike is a simple formula off Ah x W = Wh. So, the standard Shimano STEPS battery is 17.5Ah on a 36v system. This gives you 630Wh. The Bacchetta Pronto uses a 14Ah battery on a 48v system. This gives you 672Wh. As you can see, the smaller battery of the Pronto with a higher wattage actually gives you more energy than the larger, Shimano battery.

The next part of the equation is type of riding. Obviously, if you are riding along the beaches, all other things being equal, your battery will last more miles than if you are riding in the mountains. If you are riding off-road, you will get significantly few miles per charge than on-road. For example, when riding a STEPS equipped ICE Adventure, in the highest level of assistance I could go about 25 miles. When going off-road with some good climbing, the range was about 12.

It goes without saying that choosing a lower level of assist will allow you to go further. My current ride, a Bacchetta Pronto, shows that the battery will go 102 miles in the lowest setting and only 40 miles in the highest one. While it is fun running the motor in its highest level, it will clearly burn the battery on your e-bike sooner.

I think this is the hardest one to quantify, but ultimately one of the most important. What are your expectations of your e-bike or trike? Are you normally a 10mph rider hoping to be able to keep up with your friends doing 14mph? Are you a club rider doing 20mph but want to keep up with the A group doing 24? Your expectations really matter.

If you are a 10mph rider and you want to go 14mph with assist, you are essentially asking the motor to provide that additional 4mph. If you want to do 16mph, you are asking even more of your motor. This, in turn, will reduce the efficiency of your e-bike. 

If you normally ride 14mph and are expecting to go over 20mph with your e-bike, but your motor has a top end speed of 20mph, you will be sorely disappointment. So instead you decide to go with a class 3 system that will provide assistance up to 20mph. While you can go over 20mph, are are still only capable of riding 14mph on your own. For every mile an hour faster you want the e-bike to take you, you are reducing the efficiency of the battery.

This became overly apparent to me recently. I normally ride with my friend, Bruce, and his trike will go 28mph. My bikes always have a cut off of 20. It was getting frustrating always lagging just a bit behind, so we reset the maximum speed (the joys of being the builder) to 28mph. While I was instantly able to keep up, my battery efficiency dropped by close to 50%!

I hope this helps you understand the vagaries of e-bikes and the efficiency of their batteries. As the products evolve, we will see larger batteries and more efficient motors come to market. But ultimately, no matter what the marketing hype says, the factors listed above will give you the best idea of how far your e-bike will go.

Bent Up Cycles has a variety of e-bikes and e-trikes in stock. Feel free to peruse our website and give us a call/email/text if you have any questions!