I'm confused why you are asking about CCS DC Fast charging but also referencing chargers and their maximum capacity?
CCS Charging relies on the charger in the charging station not the vehicle.
The charging station is directly connected to the vehicle battery via the high current DC connectors and the BMS tells the charging station (via the comms) how fast to charge and when to stop based on its direct on board monitoring of the battery pack. (greatly simplified of course)
This is similar to Chademo except the CCS communication protocol runs over PLC rather than CAN bus. There is negotiation between the BMS and Charging station to ensure compatibility and charge voltages/currents, ground fault checking etc. prior to any charging taking place.
You could get away with no on board charger at all if you only wanted to use DC fast charging.
Mike
CCS Charging relies on the charger in the charging station not the vehicle.
The charging station is directly connected to the vehicle battery via the high current DC connectors and the BMS tells the charging station (via the comms) how fast to charge and when to stop based on its direct on board monitoring of the battery pack. (greatly simplified of course)
This is similar to Chademo except the CCS communication protocol runs over PLC rather than CAN bus. There is negotiation between the BMS and Charging station to ensure compatibility and charge voltages/currents, ground fault checking etc. prior to any charging taking place.
You could get away with no on board charger at all if you only wanted to use DC fast charging.
Mike
