About: CCS2 DC EV Charging

Modified on Thu, 13 Feb at 3:57 PM

CCS2 Plug Pinout

Starting the DC Charge

Step	Vehicle State	EVSE State	Communication	Description
1	Vehicle parked, inlet ready – Vehicle’s Type 2/Combo inlet is unlocked and awaiting connection	Idle – EVSE is powered up and pilot signal at +12 V (AC pilot line)	– CP Voltage at ~12 V (no PLC comm yet)	The vehicle is not yet connected. The EVSE sets the AC Control Pilot (CP) to +12 V, indicating it’s idle and looking for an EV connection.
2	Plug inserted – Vehicle registers mechanical connection and lock engages	Detect vehicle – EVSE detects vehicle presence via pilot transition	– CP transitions to ~9 V (State B), beginning handshake on CP line	As soon as the Combo connector is inserted, the vehicle resistor on the CP line pulls the pilot signal from 12 V to ~9 V, indicating the presence of a vehicle.
3	Handshake initiated – EV locks cable, readies for DC communication	Handshake – EVSE readies PLC communication	– PLC handshake begins – Possibly ISO 15118 or DIN 70121 session start	The vehicle and EVSE initiate high-level communication over the Power Line Communication (PLC) channel, exchanging parameters such as EV battery voltage, SoC, etc.
4	Negotiates charge parameters – BMS requests voltage/current	Negotiates – EVSE decides max current/voltage, checks EV requests	– Ongoing PLC session messages	The BMS (Battery Management System) in the EV requests certain current/voltage. The EVSE confirms it can meet these limits (or adjusts them). They finalize a charging plan.
5	Pre-charge – EV contactors open, waiting for stable DC voltage	Applies pre-charge – EVSE ramps DC bus up to requested pre-charge level	– PLC messages: “Pre-charge step”	The EVSE applies a low DC voltage/current so the EV can check continuity and measure the system’s voltage. EV contactors remain open until the pre-charge voltage is stable.
6	Contactors close, current flow begins	Full power – EVSE closes contactors and provides full DC power	– PLC messages: “Ready to charge”/“Charging in progress”	Once the pre-charge is validated, the EV closes its internal HV contactors. The EVSE contactors are also closed, and DC current starts flowing according to the negotiated limits.

Stopping the DC Charge

Step	Vehicle State	EVSE State	Communication	Description
1	Actively charging – EV is drawing current, contactors closed	Delivering power – EVSE provides DC current at negotiated limits	– PLC session ongoing – “Charging in progress”	Normal DC fast charging is in progress. Both sides maintain contactors closed and exchange live data (EV battery status, desired current, etc.) over PLC.
2	Request stop – EV or user signals to end charge (e.g. SoC target reached, user presses stop)	Receives stop request – EVSE prepares to reduce current	– PLC message: “Stop charging”	The EV BMS signals it wants to reduce current to zero, or a user command notifies the EVSE. Communication instructs the EVSE to ramp the current down.
3	Reduces current to zero – EV waits until DC current reaches zero, opens internal contactors once safe	Ramp-down – EVSE safely ramps down output current to zero	– PLC message: “Current ramp-down”	The EVSE lowers its DC current output to zero in a controlled manner. Once zero current is confirmed, the EV opens its internal contactors.
4	Contactors open – EV ensures no current flow and finalizes the session	Stops DC supply – EVSE opens contactors, transitions pilot back to AC idle state	– PLC session can end – CP line returns to ~9 V or ~12 V (if unplugged)	When the EV contactors are open, the EVSE also opens its DC contactors. The EVSE can revert the pilot to ~9 V (still connected) or ~12 V (if the plug is removed immediately).
5	Cable unlocked / physically disconnected – EV user removes connector	Idle – EVSE fully shuts down DC circuits, CP at 12 V	– No further communication	The vehicle unlocks the inlet (if not already). The user removes the Combo plug. The EVSE ends the session, pilot is back at 12 V, and no PLC communication is active.