Last updated on 8 April 2024
When we think about installing a charging station at home, we usually think about its power. But this is far from the only factor that determines the maximum charging power that can actually be achieved.
There 4 four factors to consider:
These factors are intrinsically linked. All these four elements determine the maximum power at which your electric vehicle can be charged. The limiting factor will be determined by the weakest of these four elements.
It is also important to think in terms of current rather than power.
Your type of network connection and the voltage to which you connect your charging station will be important, as these networks do not tolerate the same charging power.
Find out more about installing home charging stations.
The other essential constraint is the vehicle's on-board charger, or rectifier. A rectifier is used when the direction of current is from AC to DC, and an inverter is used when the direction of current is from DC to AC. But it is the same equipment.
The vehicle's on-board charger is the device that recharges the vehicle, and into which you insert your charging cable. This charger will also define the power and voltage at which you can charge your vehicle.
The vehicle's on-board rectifier has a crucial influence on charging options.
Currently, few vehicles can charge at 22kW at low voltage, as they rarely have on-board chargers with this power. The vast majority of electric vehicles accept up to 11 kW in three-phase.
In Brussels, however, 22 kW home charging stations must be limited by software to a maximum of 11 kW.
Amperage indicates the intensity of the electric current that can flow through a surface, in this case an electric wire, per second. Imagine for a moment that your electric wire is a garden hose. The amperage corresponds to the water flow rate through the pipe.
Similarly, the on-board charger in your electric vehicle can tolerate a certain amperage. It can be 16 or 32 amperes per phase.
It is this notion that defines the power at which you will be able to charge your vehicle.
If your vehicle is equipped with an 11 kW charger, it will therefore be impossible to charge your vehicle at 7.4 kW single-phase, as this power corresponds to 32 amperes single-phase. However, 11 kW chargers only tolerate 16 amperes per phase. In this case, you will be limited to 3.7 kW.
To charge your vehicle at 7.4 kW, it must be equipped with a 7.4 kW single-phase on-board charger or a 22 kW three-phase on-board charger, and be connected to a 7.4 kW charging point.
You must choose your charging station according to the type of connection to the network, as well as to the on-board charger in your vehicle. The most limiting of these factors will define the total power at which your vehicle will be charged.
To sum up, here are the key points to bear in mind:
These limits apply to home charging stations (mode 3), and not to outdoor fast charging stations (mode 4). In this case, the maximum charging power will depend solely on the maximum power of the terminal and the type of plug/charger installed in the vehicle.
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