Standards body the Society of Automotive Engineers (SAE) International has announced that it has finalised its standardisation document for EV chargers based on the North American Charging Standard (NACS) system developed by Tesla.
Tesla's design for the NACS connector will now technically be known as the SAEJ3400 connector, and its technical details made public for the companies other than Tesla to use for manufacturing and repairing the connectors themselves.
The publication of the standard aims to promote interoperability and ease the coalescence of the EV industry around the Tesla charging system. This is the culmination of NACS becoming the dominant charging system in North America, which began with Tesla announcing a string of deals with all but a few major automakers to be built with NACS charging ports, starting in 2025.
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The completion of standardisation now also means that certified adapters can be built for drivers of EVs without NACS portals, effectively allowing all EVs on the road to use the Tesla system. Even competing automakers planning their own branded fast-charging stations have said they will offer NACS cables and connectors by default.
SAE says that the new standard covers the general physical, electrical, functional, safety, and performance requirements for NACS charging, giving guidance to manufacturers on how to design and install chargers using technology originally designed by the Elon Musk-led firm.
The use cases encompassed under the standard include charging "which can be hand-mated and is capable of transferring either DC or AC single-phase power using two current-carrying contacts."
"But ever since Ford then GM announced deals with Tesla to use NACS for their EVs in North America, there have been questions around all the above functions of the charger. How would these customers authenticate and pay, negotiate the charge, and all the rest?" says Derek Kerton, chairman of the Cleantech Council.
And the SAE's standard primarily addresses the auxiliary aspects of the charging experience, such as in designing protocols for payment and data exchange between the charger and EV. However, since Tesla began opening up its own chargers, concerns have lingered about Tesla's use of any data potentially garnered from competitors' vehicles.
But the publication of the standard has nonetheless been widely hailed as a boost for the wider industry and is seen as a key step towards greater reliability for charging across the board.
"The new SAE J3400 connector will ensure that any vehicle or charging equipment supplier or manufacturer will be able to use, manufacture, or deploy the connector and expands charging access for current and future EV drivers across the country," says the Joint Office of Energy and Transportation.
How standard is standard?
Tesla has long been open to sharing access to its charging network, as well as supplying its connectors to other operators, but it remains to be seen if the Tesla network will be as reliable for EVs from other OEMs as it is for Tesla vehicles. Similarly, Tesla is still free to alter the connectors that it continues to manufacture, and to diverge from the new industry standard.
SAEJ3400 "will look of course a bit different to that what Tesla has defined as its NACS", says Wulf Schlachter, founder of mobility consultancy DXBe Management.
And this divergence from Tesla's own NACS charge points could lead to an inconsistent user experience, some industry figures warn, with any lingering barriers to interoperability after the promise of standardisation playing into Tesla's hands.
"That is the trap the OEMs are falling into," cautions Martin Wosnitza, head of public charging at German automaker Audi, warning that other EV manufacturers "will be forced to use NACS, and then it will not work as well as Tesla's version".
"Tesla can just say, 'look, it works well for us, come and buy a Tesla,'" Wosnitsza warns.
Ciaran has written about finance, politics and culture. He is passionate about e-mobility and what it means for our way of life.
Ciaran has a Masters in Ancient Philosophy from Oxford University.
