EV Charging Modes Explained

IEC 61851 divides EV charging into four modes to address safety, reliability and interoperability issues. Each mode defines how the vehicle is connected to the power supply, the maximum current and voltage allowed, and the communication required between the charger and the vehicle.

Mode 1 – Basic Charging

In Mode 1, the vehicle is plugged directly into a household or industrial socket with no additional control equipment. The permitted current is limited to 16 A at 250 V (single phase) or 480 V (three phase). Since there is no communication or safety function built into the cable, many countries prohibit or restrict Mode 1 charging to prevent over‑current or overheating hazards.

Mode 2 – In‑cable Control

Mode 2 improves safety by integrating a control and protection device into the charging cable. This in‑cable device (IC‑CPD) monitors temperature and current and can interrupt the power supply if a fault is detected. It allows higher currents up to 32 A at 250 V or 480 V and provides basic communication between the vehicle and the cable.

Mode 3 – Smart Charging

Mode 3 uses a dedicated charging station with built‑in control and protection functions. The charging cable is permanently connected to the station, and the vehicle plugs into a standard connector. Mode 3 supports higher power levels up to 43.5 kW AC and enables advanced features like load balancing, time‑of‑use scheduling, and grid services.

Mode 4 – DC Fast Charging

Mode 4 provides direct current (DC) charging at high power levels, typically 50 kW and above. The charging station contains the AC‑DC converter and supplies DC power directly to the vehicle battery, bypassing the vehicle's onboard charger. This enables rapid charging in 20‑30 minutes for highway applications.