What Do The Letters and Numbers on E-bike Batteries Mean?

If you take a look at any e-bike shop or indeed any e-bike battery you will soon find various numbers like 5V1A, 36V, 10AH, 500W, 624 Wh? What do they all mean? We will take you through all the main numbers that you need to know and tell you exactly what each one means in layman’s terms… 

What Does “V” Mean on an E-Bike Battery?

This letter means “Volts” which is the amount of energy given to an electronic circuit. But what does that mean? If you consider the battery as a water pipe the voltage (V) is the pressure that water is flowing. So the higher the “V” number the more power it could deliver to the mother. E-bikes mostly come with 36V, 48V or 52V varieties and the difference between them is about power and performance.

What you might not know is that you can calculate the peak power of an e-bike by multiplying the voltage of the battery by the maximum current the e-bike can handle. The maximum current is determined by the e-bike’s controller and is usually somewhere between 15-30 amps. So with that in mind a 48V battery and a 20 amp peak controller would theoretically be capable of a nominal 960 watts of power. You will often find manufacturers will lie about this “V” number and undersell it as way less than it actually is. They do this to get around UK e-bike laws and regulations.

What Does “Ah” Mean on an E-Bike Battery?

This stands for “Amp Hours” and this is a measurement of a battery’s storage capacity. So let’s take the battery from my own E-bike which reads 13 Ah. One of the easiest ways to understand this is to double the number. So that becomes “26” and this is the number of miles the e-bike can go for under ideal conditions. So in reality a 13 Ah battery will mean you can ride between 13 and 26 miles. Why is this number such a broad spectrum? Because there are many factors to take into account. The weight of the e-bike, the weight of the rider, the riding conditions, the surface, the temperature, all these things affect how long the battery will last.

The easiest way to think about it is by calling it the number of miles it can go, because a 13 Ah e-bike battery will pretty much always travel for that amount and then some. But how far extra depends on the many factors I listed above.

What Does “Wh” Mean on an E-Bike Battery?

This stands for watt-hours, but some will say “mWh” which means milliwatt-hours. This is a convenient way to compare the total amount of energy to other batteries and it is a maths sum of the two previous letters. The sum is: V X Ah = Wh. So on my battery, it says 48V – 13Ah. So 48 X 13 = 624!

The good news is you don’t have to work out that power you have left because most e-bikes have a battery power meter anyway. But these are still good things to know as it does mean you can compare power and longevity with other e-bikes to make sure you get the right one for your needs.