Battery knowledge

What do watts, volts, and amps mean for my eBike battery?

The battery is the power source of your eBike. It supplies the drive unit with power and has a critical influence on the range. To understand how your battery works, it is important to know terms such as watt-hours (Wh), amperes (A), ampere-hours (Ah), and volts (V). We will familiarize you with the basics and explain the physical units and their meaning in the context of eBike batteries.

Definitions

What is volt?

Volt is the physical unit of electrical voltage and indicates the potential difference between two poles. This is what makes the flow of electricity possible in the first place.

What is ampere?

Ampere is the physical unit of electric current and indicates how much current is flowing.

What do ampere-hours mean in the context of eBike batteries?

Ampere-hours is the physical unit for the electrical charge contained in the battery. It indicates how much power can be drawn from the battery and for how long – and thus describes the capacity of the eBike battery. For example, ten ampere-hours means that the battery could deliver two amperes for five hours. (Ah = A*h)

What do watt-hours mean in the context of eBike batteries?

Watt-hours is the physical unit for the energy content of the battery. It describes the actual working capacity of the battery and is relevant for the achievable range: The higher the watt-hours, the more energy is available. For example, 500 watt-hours means that the battery can deliver 100 watts for five hours until it is discharged.

What does the energy density (Wh/kg) of the batteries mean?

The energy density also indicates how much energy content the battery contains per pound. A high value means that the battery contains a lot of energy in relation to its weight.

Relationships between watts, amps, and volts

What is the relationship between watts (power), amps (current), and volts (voltage)?

The power (unit: watt) results from the multiplication of current (unit: ampere) and voltage (unit: volt). You can therefore increase the power by increasing the current or voltage.

How does the battery affect the performance of your eBike?

When fully charged, the battery has the highest voltage (unit: V). This voltage decreases over the course of the eBike ride. In order to still deliver the same power (unit: W), a higher current (unit: A) must flow. If the current (unit A) cannot be increased further, the maximum power (unit: W) decreases. Power = voltage * current.