SAE J1772 - Battery Design

Electric Vehicle and Plug-In Hybrid Electric Vehicle Conductive Charge Coupler

SAE J1772 defines the standard for the conductive charge coupler used to connect electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) to AC charging infrastructure in North America. It specifies the physical connector, pilot signalling, and control protocols for Level 1 (120 V AC) and Level 2 (240 V AC) charging. J1772 connectors are mandated on all US and Canadian EVs and are also widely used in Japan.

Published by: SAE International
Current edition: SAE J1772:2017
Related standards: SAE J3400 (NACS/Tesla connector), IEC 62196-2 (Type 2 European connector), ISO 15118 (V2G communication)

Scope

SAE J1772 covers the physical coupler design, mating requirements, environmental sealing, current rating, and Control Pilot (CP) signalling protocol for single-phase AC charging. The Control Pilot signal between EVSE and vehicle conveys EVSE availability, current capacity, and vehicle connection state, enabling the vehicle to manage the charging session safely.

Key Specifications

Connector and Ratings

The J1772 connector has 5 pins: L1, Neutral, Ground, Control Pilot (CP), and Proximity Pilot (PP). Level 1 charging supports up to 16 A at 120 V; Level 2 supports up to 80 A at 240 V AC. The proximity pilot circuit detects connector insertion and locks the connector while current is flowing to prevent disconnection under load.

Control Pilot Signalling

The EVSE generates a 1 kHz PWM signal on the CP wire; duty cycle encodes the maximum current available (e.g., 16% = 10 A, 25% = 16 A). The vehicle changes the CP line resistance to signal its state: ready to charge, charging active, or ventilation required. This handshake ensures charging only begins when the vehicle requests it and the EVSE has confirmed availability.

Disclaimer: This is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.

References

SAE J1772:2017, SAE International