Understanding J1772 (J17LM) and J1931 (J19LM) EV Charging Standards
The electric vehicle (EV) charging landscape is evolving rapidly, with various standards emerging to facilitate safe and efficient charging. Two prominent standards, J1772 (J17LM) and J1931 (J19LM), often cause confusion due to their similar names and overlapping functionalities. This article aims to clarify the differences between these two standards, ensuring EV owners and enthusiasts make informed decisions about charging infrastructure.
J1772 (J17LM) - The North American Standard
Introduced in 2001, the J1772 standard, also known as SAE J1772, is the most widely used charging standard in North America. It defines the electrical, signal, and communication protocols for conductive charging of EVs. The 'LM' suffix in J1772 refers to the latest revision of the standard, which was published in 2019.
- Connector Type: J1772 uses a five-pin connector, with two power pins, two control pins, and one ground pin.
- Power Levels: It supports both Level 1 (up to 1.92 kW) and Level 2 (up to 19.2 kW) charging.
- Communication Protocol: J1772 uses the Controller Area Network (CAN) bus for communication between the EV and the charging station.
J1931 (J19LM) - The Fast Charging Standard
Published in 2010, the J1931 standard, or SAE J1931, builds upon the J1772 standard to facilitate fast charging capabilities. The 'LM' suffix indicates the latest revision, released in 2019. J1931 is designed to support higher power levels and faster charging speeds.
- Connector Type: J1931 uses the same five-pin connector as J1772, but with additional pins for higher power and faster charging capabilities.
- Power Levels: It supports Level 2 charging (up to 19.2 kW) and fast charging (up to 100 kW).
- Communication Protocol: J1931 uses the same CAN bus communication protocol as J1772, but with additional messages for fast charging capabilities.
Key Differences Between J1772 and J1931
| Feature | J1772 (J17LM) | J1931 (J19LM) |
|---|---|---|
| Maximum Power | Up to 19.2 kW | Up to 100 kW |
| Connector Type | Five-pin | Five-pin (with additional pins for fast charging) |
| Communication Protocol | CAN bus | CAN bus (with additional messages for fast charging) |
While both standards share some similarities, the primary difference lies in their power capabilities and charging speeds. J1772 is designed for Level 1 and Level 2 charging, while J1931 supports fast charging capabilities, enabling EVs to charge at higher power levels and speeds.
Compatibility and Coexistence
It's essential to note that J1931 is designed to be backward-compatible with J1772. This means that EVs equipped with J1772 connectors can still charge using J1931 charging stations, although at lower power levels. Conversely, EVs with J1931 connectors can charge using J1772 charging stations, but they may not be able to utilize the fast charging capabilities.
As the EV charging infrastructure continues to evolve, it's crucial for EV owners to understand the differences between these charging standards. By doing so, they can ensure they have access to the appropriate charging infrastructure and make the most of their EV's charging capabilities.
