What is the difference between AC and DC EV chargers?

An electric car battery is always charged with direct current (DC). The difference is where the conversion takes place. With an AC charger, the station supplies alternating current and the car's on-board chargerGlossary · EV chargingOn-board Charger (OBC)The converter inside an electric vehicle that turns the station's AC into DC and sets the maximum AC charging power. does the conversion. Charging speed is therefore limited by the on-board charger's power, often 7.4 or 11 kW, even if the station could deliver more. With a DC charger, the converter is inside the station and feeds the battery directly, at power levels that often exceed 50 kW.

For example, a car that charges overnight on a home wallboxGlossary · EV chargingWallbox (home wall charger)A wall-mounted EV charger that charges with AC from its own circuit in the panel and communicates with the vehicle for safe charging. can take a large part of its charge in less than an hour at a DC station. DC stations, however, need a strong three-phase supply and a larger investment, which is why they are found mainly on motorways, at public stations and in business fleets.

For homes and workplaces, where the vehicle stays parked for hours, an AC charger is usually enough. Before choosing, check the power of the car's on-board charger: a 22 kW station will not charge a vehicle that accepts only 7.4 kW on AC any faster.