How to calculate the speed and range of an ebike?


In many situations, especially when replacing a battery in an existing installation, the required voltage is determined by the controller and can not be easily changed. It should be remembered that the voltage determines the maximum speed at which the vehicle will move. If you know the voltage [V] and the rpm value of the motor, it is easy to calculate what speed the vehicle will reach for a given voltage.

The range of the battery depends of course on how much effort we will make while pedaling, how fast we travel and what is the area where we are.

Driving type Approximate energy consumption
Street (Minimum electric drive assistance – using electric drive only at hill, driving below ~ 30 kph) 6-8 Wh/km
Standard (~40 kph with pedaling, continuous assistance of the electric motor) 9-12 Wh/km
Race (without pedaling / with additional load / fast riding) 14-20 Wh/km

Estimate the distance you have to travel, multiply it by the appropriate Wh / km from the table above and you will get the total minimum number of Wh needed to cover this distance. Then Wh which you have estimated, divide by the nominal voltage of the battery, and get an estimate of the minimum amp-hours that you will need from the battery to drive a certain distance.