What Is The Capacity Of Battery Used In Electric Bikes?

Battery Capacity of Electric Bikes

One of the first questions new e-bike owners ask is, “How far can I ride between charges?” While calculating battery capacity can give you a rough idea of how many miles you go before needing to recharge, it’s by far not the only factor in determining your bike’s longevity on the road. While it’s important to have a high-quality battery for an optimal ride, how you use your battery is ultimately as important as its size.

In other words, a bigger battery isn’t always the best battery.

If you’re struggling to parse through battery terminology, we have you covered. Below, you’ll find a basic breakdown of measuring battery capacity and determining what that means for you in a practical sense.

What Kind Of Batteries Do E-Bikes Use?

Over the years, the technology of e-bike batteries has evolved tremendously. This has led to breakthroughs in e-bike efficiency, making e-bikes more and more tenable as a convenient, environmentally-conscious replacement to gas-reliant modes of transportation.

The vast majority of e-bikes rely on lithium-ion batteries (Li-ion), including the bikes sold at Story Bikes. Over the years, Li-ion batteries have largely replaced previous options like lead batteries and nickel-metal hydride batteries. Why? They’re versatile, long-lasting, and work perfectly with high-capacity, low power machines like electric bicycles. Plus, they can be made to conveniently fit into a wide variety of spaces, including inside your e-bike.

Story Bikes run on 36v 7AH Samsung Lithium Ion batteries and come with charging units and A/C adapters that plug directly into the bike. It takes only 3 hours to charge your bike from empty to full.

What Do These Terms Mean?

Now that you know the type of batteries we use, you’re probably wondering what abbreviations like V and AH stand for and how they relate to battery capacity.

Battery power comes down to volts, amps, and watts. An analogy frequently used is to think of electricity as water flowing through a pipe. Amps are the volume of water and voltage is the water pressure. When you combine the volume of water with its pressure, you get an estimate of the water’s potential power – or, in this case, watts.

How does that translate to battery power? Here’s a brief breakdown:

V (Volts)

Volts are a basic measure of electric power. In general, a higher voltage means a stronger battery, but many other factors come into play (more on that below).

AH (Amp Hours)

Think of your amp hours sort of like the gas tank in a car. It’s a measurement of how much energy a battery can hypothetically store.

Watt hours (WH)

Watt hours (wh) are used to get a rough determination of how long a battery lasts. This is where you need to do a little math. To calculate watt hours, multiply the voltage by the amp hours. With Story Bikes batteries, for example, you would multiply 36 times 7 to get 252.

What do these numbers tell us? In and of themselves, not a whole lot actually.

Numbers give us a rough sense of a battery’s power, but myriad other factors come into play when determining how far a bike can ride between charges. Battery capacity is contingent on the build of the bike and how you intend to ride it.

What Else Affects Battery Capacity?

How you ride your bike determines the battery’s capacity. If you’re going over hilly terrain, your battery will drain faster than it would on a flat surface. The same can be said for the level of pedal assist system (PAS). A steady pace at a lower PAS level will expend less battery power than max speed at the highest PAS level.

However, a large amount of battery capacity depends on an e-bike’s PAS technology and components. The difference between torque sensing and cadence sensing has a massive impact on battery life.

Both torque sensing and cadence sensing PAS determine the amount of assistance the motor provides at any given point of your ride. With cadence sensing PAS, magnets and sensors are used to determine the amount of assistance. A cadence sensor determines how much assistance based solely on the assist level being used and simply turns on and off if you are pedaling. A cadence PAS is less responsive and efficient.

With torque sensors, on the other hand, motor assistance is determined by the pressure applied to the pedal. Essentially, if you’re exerting more pressure on the pedals, this instantly tells the bike you need more assistance. Not only does this make for a much more responsive ride, it’s easier on the battery as power is not wasted when slowing down or going downhill. An e-bike with torque sensors can get a lot more mileage, even while navigating hilly terrain, with a much smaller battery. Torque sensing PAS is newer and more efficient technology.

We use torque sensing over cadence sensing on our e-bikes, which provides a smoother, more responsive, and enjoyable ride. You will also have a longer range with torque sensing PAS than if using a cadence sensing PAS. A Story Bike has a range of up to 45 miles depending on the PAS level being used.


Battery capacity is complicated and comes down to a lot more than crunching the numbers. While indicators like voltage and amp hours can give you a rough sense of a battery’s power, a bike’s build makes a tremendous difference.

How a battery is used is just as important as its size. With a quality bike, a mid-sized battery can last a long time between charges.

If you think an e-bike is right for you, you can start your search at Story Bikes. We offer step-through bikes, road bikes, and commuter bikes at reasonable prices. For every bike we sell, we give a bike to a student in Zimbabwe.

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