How does an EV charger work?

Power from the electricity grid is alternating current (AC) by nature. The electric power of a battery is direct current (DC) by nature. Therefore, to charge an electric vehicle from the grid, power must be converted from AC to DC.

When plugging an electric vehicle into an AC charging station, power from the grid is fed to the car via the vehicle inlet using the charging cable and connector. The onboard AC/DC converter converts AC power to DC power, suitable for charging the battery.

Due to the limited space inside a vehicle, the onboard charger is limited in size and weight. Therefore, onboard chargers typically have a power ranging between 1.9 kW – 43 kW.

To increase the charging power further, the AC/DC converter must be moved outside the vehicle and placed in an off-board charger. This is known as DC charging. DC power is directly fed to the car via a DC charging inlet. With no size or weight restrictions, the off-board charger can typically deliver up to 350 kW.