What determines the charge speed?

The charge speed is expressed in 'kW..' You can find different chargers at our stations: 50 kW chargers and 150 kW. The charge speed is determined by the vehicle and depends on multiple factors.

Influence of battery % on charge speed

The graph underneath shows an example of a charge curve. It shows the charge speed (vertical axis, expressed in kW) depending on how full the battery is (horizontal axis).


In this example, the charge speed slowly drops when the battery is about 70% full. The drop is steeper when the battery reaches 80%, and at 90%, the charge speed is already reduced very significantly. The reason is that as the battery gets more full, it has to be charged more slowly. In this example, fast charging above 80 to 90% of the battery is less useful since charging will get progressively slower.

Each vehicle's charge curve is different and depends on the design choices made by the vehicle manufacturer. 

Influence temperature on charge speed

Another factor that can have a significant influence on charge speed is the temperature of the battery. A battery works optimally if the temperature is not too high and not too low. In practice, this is usually between 68°F and 86°F, although some cars function best with a battery around 104°F.

A battery can get very cold in winter, for example, if the vehicle is parked outside. This can cause charging to be (much) slower. Conversely, a battery can become very warm during a hot summer day, and this can also cause charging to go slower. The influence of the temperature on the charge speed is different for each vehicle model. Some models are equipped with thermal management for the battery. This way, the battery can be cooled or heated, depending on the circumstances. However, it can take a while before a battery pack is completely heated up on a cold day.

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