Every EV battery stores energy as DC (direct current), but most home and public power comes as AC (alternating current) — that mismatch is the whole reason two separate charging systems exist.
AC charging (Level 1 and 2)
The car's onboard charger converts incoming AC power to DC before it reaches the battery. This conversion hardware is physically limited in how much power it can handle, which caps AC charging speed even on a strong circuit.
DC charging (Level 3 / fast charging)
The conversion happens inside the charging station itself, which can house much larger, more powerful converters than fit inside a car. That's why DC fast chargers can deliver 10-20x the power of a home Level 2 charger.
Why this matters when picking a station
A high kW number on a station only matters if it's a DC connector — an AC station's speed is limited by your car's onboard charger regardless of what the station itself is rated for.
Does DC charging need a different plug than AC?
Often yes — CCS and CHAdeMO are DC-only connector standards, while J1772 and Type 2 are AC-only, though CCS actually combines a J1772/Type 2 head with two extra DC pins in one connector.