What is the difference between AC and DC charging?

With AC, the car's onboard charger converts the current, which limits power, often to 11 or 22 kW. With DC, the charger carries the converter itself and can deliver far more.

Explained in

Charging hardware · Stop 01Why are there AC and DC chargers?Batteries store direct current, the grid delivers alternating current. AC and DC chargers differ in one thing above all: where the current is converted.

With AC charging, the onboard charger in the car turns alternating current into direct current. It has to fit into the car, so its power is limited, often to 11 or 22 kW. For a car parked for hours, that is enough.

From “The converter moved out of the car”, stop 01

Terms

  1. Onboard chargerThe converter in the car that turns AC from a wallbox or public AC charger into DC for the battery; its rating limits AC charging power.
  1. Which connector do public chargers in Europe use?AFIR requires at least Type 2 at public AC points and Combo 2 (CCS) at public DC points. One car inlet takes both: Type 2 above, two DC pins below.
  2. Why do fast chargers have such thick cables?A cable is sized for current, and heat grows with the square of it. At the highest currents, a liquid circuit cools cable and connector so the cable stays manageable.
  3. Why do two cars at one charger get less power?Many chargers divide their power modules between two outlets. A car that is fuller asks for less, so the modules move to the other car.
  4. What does charger uptime mean?Uptime is the share of time a charge point is online, available and delivers energy. At 97%, it may be out for about 11 days a year at most.
  1. U.S. Department of Energy, Alternative Fuels Data Center: How do all-electric cars work?. https://afdc.energy.gov/vehicles/how-do-all-electric-cars-work. Checked 09 Oct 2026.