AC / DC charging - What is the difference and what should I use to charge my electric car?

What is AC / DC?

AC – alternating current

AC – English for Alternating Current – refers to alternating current. This current comes from German household sockets and most wallboxes. Alternating current (AC) regularly changes its polarity, i.e. the current changes direction 50 times per second.

DC – direct current (Direct Current)

DC – stands for Direct Current and is the equivalent of the German Gleichstrom. In contrast to alternating current, direct current (DC) is constant and only flows in one direction. The polarity remains the same, which is why it is also referred to as direct voltage.

Batteries always store direct current (DC). When charging an electric car, alternating current (AC) must therefore first be converted into direct current – either in the car (AC charging) or at the charging station (DC charging).

You can charge your eCar with alternating current (AC) or direct current (DC). Both variants have their advantages and disadvantages.

What kind of charging stations are there?

Electric cars should be charged at charging stations so that they can be charged quickly. There are AC charging stations (normal charging stations), which can charge with a charging capacity of up to 22 kW, and DC charging stations (fast charging stations), which usually charge with significantly higher capacities (e.g. 50 kW, 150 kW or more).

AC charging stations emit alternating current. This is converted into direct current in the car by the on-board charger.
DC charging stations transform the alternating current in the station and then pass direct current directly to the battery. This conversion in the charging station makes much higher charging capacities possible, which is why DC charging is significantly faster. However, fast charging is usually associated with higher costs and is mainly used in public areas, e.g. at highway filling stations.

→ DC charging is suitable for long journeys with short stops.
→ AC charging is useful when the vehicle is stationary for longer periods (e.g. at home, at work, when shopping).

AC charging stations

• – Charging power up to 22 kW

• – emit alternating current

• – Slower charging (conversion in the car)

• – Costs are lower

• – in household sockets (Schuko) only as an emergency solution – wallbox recommended

• – Ideal for parking for approx. 20 minutes or several hours

DC charging stations

• – Charging capacity mostly from 50 kW (sometimes up to 350 kW)

• – emit direct current that has already been converted

• – Charging significantly faster

• – Costs are higher

• – in public spaces, e.g. at highway filling stations or fast-charging parks

• – Ideal for short stopovers

Overview: These are the advantages and disadvantages of AC and DC

AC charging (alternating current)

Advantages

• – High availability, also possible at home

• – More cost-effective than DC charging

• – Technically less complex

• – More battery-friendly for everyday use

Disadvantages

• – Lower output (usually up to 11 or 22 kW)

• – Longer charging times, as conversion takes place in the car

DC charging (direct current)

Advantages

• – Significantly higher charging speeds

• – Ideal for long distances

• – Direct feed into the battery (no conversion in the car)

Disadvantages

• – Higher costs (installation & electricity price)

• – less common than AC

• – Frequent fast charging can put more strain on the battery

Which plugs fit which stations?

• – AC charging: Type 2 (standard in Europe), rarely type 1 for older imported vehicles

• – DC charging: CCS (Combined Charging System) standard in Europe, CHAdeMO on the decline

• – Tesla: also CCS-capable in the EU

Normal charging stations (AC) can be used with household plugs (Schuko), CEE plugs, type 1 or type 2.
Special eAuto charging cables with CCS or CHAdeMO plugs are required for fast charging stations (DC).

You can find more exciting eMobility facts in our blog.