AC charging goes through the car's onboard charger, so it is limited to that charger's rating, usually 7.2 kW or 11 kW: slow, cheap and suited to overnight charging at home. DC fast charging bypasses the onboard charger and feeds the battery directly at 25 kW to over 150 kW, adding a lot of range in 30 to 60 minutes on a trip, but it usually costs more per unit and slows down above about 80%.