What determines the Electric car Charge Speed?

The charge speed is expressed in ‘kW’. The charge speed is determined by the vehicle and depends on multiple factors.

Influence of battery % (SoC) on charge speed

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

In this example, the charge speed starts to slowly drop 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.

The charge curve of each vehicle is different and depends on the design choices made by the vehicle manufacturer.

What determines the charge speed? – FastNED Charging Network

Learn about the FastNED charging network and the new Autocharge technology

In winter a battery can get very cold 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, on a cold day, it can take a while before a battery pack is completely heated up. Fast charging is also an effective way to heat up your battery.