SAE J3400: Shaping the Future of Electric Vehicle Charging in North America

Sign up for daily news updates from CleanTechnica via email. Or follow us on Google News!

Industry experts emphasize that the focus is on developing a comprehensive charging system rather than just a basic plug, sharing insights on best practices.

The automotive sector made significant strides today at The Battery Show in Detroit, with SAE International announcing the release of its NACS J3400 Recommended Practice document.

The document, formally titled “SAE J3400TM: NACS Electric Vehicle Coupler Technical Recommended Practice,” serves as a “blueprint” aimed at inspiring new product development from suppliers. The document will soon undergo testing by OEMs and third-party organizations like UL, according to Rodney McGee, chairman of the SAE J3400 NACS Task Force and a research engineer at the Transportation Electrification Center at the University of Delaware.

“We expect more interoperability testing and collaboration within the industry as we seek enhancements for the document,” McGee stated. “Our objective is to transition from a recommended practice to an established standard with minimal changes between the two.”

NACS is also being officially rebranded, now representing the “North American Charging System,” rather than a “Standard,” to better convey that it encompasses a system of industry standards that extend beyond just the vehicle coupler, as stated in SAE’s announcement.

McGee mentioned that transitioning to J3400 enables the industry to incorporate beneficial innovations that have emerged since the last major North American EV standard, J1772, was initiated in 1996 and gained widespread acceptance in 2009. He pointed out two primary reasons the shift toward NACS is set to enhance charging infrastructure in North America. Firstly, as more new EVs gain access to Tesla’s renowned charging network, other operators will need to equal Tesla’s user-friendliness and reliability to remain competitive. Secondly, Tesla’s network outperforms those built by OEMs and suppliers, as Tesla’s engineers developed both the vehicles and the EV charging stations.

“When [Tesla] established the foundation of NACS over a decade ago, their focus was always on both the vehicles and the charging infrastructure,” McGee explained. “This dual perspective results in a different approach compared to when J1772 was introduced, as OEMs lacked significant investments in energy infrastructure at that time. Now they are engaged on both fronts, making NACS’ system design integral to mass electrification: developing a connector that accommodates various voltage types for AC charging, as well as multiple connection methods. We’ve really integrated many of these crucial aspects to establish the standard for electrifying transportation in North America, particularly for passenger vehicles.”

In contrast to J1772, J3400 will facilitate digital communication between vehicles and chargers (unlike J1772, which utilizes what McGee described as a “very simple analog communication method”). The task force aims to introduce features such as minimum required error codes, similar to those used by the ChargeX consortium for DC fast charging, into the new AC J3400 standard. Furthermore, J3400 includes vehicle-to-grid (V2G) capabilities and backup power requirements.

Additionally, J3400 will modernize the North American charging landscape by permitting carry-along cord sets. These personal cords, already common in many parts of the world, allow for less costly EV charging stations since they only require a standard port, eliminating the need for bulky cables and connectors that require larger investments and ongoing maintenance. This development will improve charging access for lower-income drivers and residents of apartments.

“The components that remain in place when there’s no electric car present need to be minimized,” McGee emphasized. “They should blend into the infrastructure, which will significantly promote curbside charging.”

The current J3400 RP indicates that the maximum amperage for the standard could reach 900 amps when drawing solely from the connector side, and up to 1000 amps when drawing from both the vehicle inlet and connector sides. “That is purely theoretical,” McGee cautioned, as no automaker has announced plans for vehicles that powerful. “In theory, NACS could allow for a maximum of one megawatt.”

On the voltage side, the revamped NACS aims to extend some of Tesla’s visionary advantages to the wider public. Tesla chargers can leverage 40-volt, three-phase power from utilities and convert it directly to 277 volts for vehicle charging, resulting in lower AC charging costs since there’s no need for an additional transformer on location. This approach also reduces the amount of copper and conduit needed.

By Sebastian Blanco, courtesy of SAE International.