You might be perplexed by the numbers on the spec sheet if you’re shopping for your first e-bike or electric scooter. What is the difference between a watt-hour (Wh) and an amp-hour (Ah)? Is it true that voltage is important? I’m not sure how big of a battery I’ll need. We’re here to help you make sense of these numbers using some fundamental physics and arithmetic.
Which spec informs me how big the battery is?
When researching an electric bike or e-scooter, you’ll likely come across a variety of battery-related data. Volts, amp-hours, and watt-hours are the three most frequent units. When it comes to energy capacity, watt-hours (again, that’s ‘Wh’) are the most useful unit. You’ll want to look for the watt-hour rating on the spec sheet if you want to compare the battery sizes for two rides. If the specifications are accurate, the larger the watt-hour rating, the larger the battery, and the longer the range.
There is no watt-hour rating; just amp-hours and voltages are listed. Help!
While most e-bike manufacturers now display battery ratings in watt-hours, many electric scooter manufacturers continue to use volts and amp-hours. Don’t be concerned, my friend. The simplest of multiplications is determining a battery’s watt-hour rating from voltages and amp-hours. Here’s how to figure it out: Ah * V = Wh
That is all there is to it. Similarly, the amp-hour rating of a battery can be determined by dividing the watt-hour rating by the voltage. To calculate the voltage, divide the watt-hours by the amp-hours. Battery ratings for the FluidFreeRide Mantis Escooter are commonly expressed in amp-hours and volts. To get the more usable watt-hour metric, simply multiply those two amounts.
Keep in mind that the above formula is an approximation because the voltage of a battery varies during use. However, it is, for all intents and purposes, the simplest way to evaluate battery capacity between different e-bikes and e-scooters. The motor on the e-bike, I’m considering is 250W. What does this have to do with range? The wattage of the motor by itself tells you nothing about the range.
A motor with a higher power Theoretically, a higher-wattage motor can drive faster or climb steeper hills for longer. At maximal demand, it will also drain your battery faster, but the wattage of a motor isn’t a fixed amount; it varies depending on how hard you drive the motor. Manufacturers’ figures are based on averages.
Furo Systems is a company that develops and manufactures Furo X a folding electric bicycle. The watt-hour, on the other hand, is an energy measurement unit (or energy storage). It basically informs you how much continuous wattage is needed to drain the battery in an hour. To put it another way, if your motor uses an average of 250W, a 250Wh battery will drain in around an hour, whereas a 500Wh battery will take two hours.
What does it mean to be big?
As previously said, the quantity of energy consumed by a motor varies greatly, but there are some fundamental rules to remember. Typical e-bike and scooter batteries have a capacity of 400-600Wh. Lightweight scooters and e-bikes are typically around 300Wh, whereas heavier, more powerful ones are closer to 1000Wh — or more.
CCX Battery by Juiced e-Bike
With a capacity of 998Wh, the Juiced Bikes CCX boasts one of the largest batteries we’ve seen.
The range of those batteries is primarily determined by how you operate your bike or scooter. Higher assist or speed settings will consume more energy by default, but other factors such as the type of motors, wheels, or sensors can also affect range.
Watts gets a lot of attention, but what about volts and amp-hours?
For the most part, knowing the watt-hour rating tells you everything you need to know about the battery capacity of an electric car. Even so, you might be intrigued about the relationship between volts and amp-hours. It’s a little complex, but keep in mind that everything below is simplified.
The most popular voltages on the market these days are 36V, 48V, and 52V, however lower and higher specifications are infrequently seen (the latter especially in the DIY market). If all other factors remain constant, a higher voltage battery will typically be able to output more power and retain excellent performance even at low battery levels.