Plug a non-Tesla into a Supercharger? It's not so simple

From the wiring to the sheet metal to the software, automakers that plan to adopt Tesla's plug for their own EVs have bigger design and engineering challenges than just changing the receptacle in the charge port.

So far, General Motors, Ford, Rivian and Volvo have committed to adopting Tesla's North American Charging Standard plugs. Stellantis and Hyundai have said they are considering making the same move. The NACS plug receptacles are scheduled to start appearing on non-Tesla EVs in 2025.

While Tesla's smaller NACS receptacle easily fits behind the charge port doors on other brands' vehicles, engineers have some work to do. And onboard software enabling non-Tesla vehicles to communicate with Tesla chargers has to be created, tested, validated and integrated.

The goal, said Sam Abuelsamid, principal research analyst at Guidehouse Insights, isn't just to open up Tesla's vast charging network to other brands. Competitors want to replicate the consistently fast and reliable charging Tesla drivers enjoy and put in the rearview mirror the often frustrating charging imbroglios early EV adopters are suffering at the patchwork network of often unreliable public charging stations.

Conrad Layson, senior alternative propulsion analyst at AutoForecast Solutions, added: "There are hookups and connections that go beyond the simple handshake signal." Charging "is seamless to the Tesla user."

The non-Tesla EVs on the road, and those ready to launch, such as the fleet and commercial versions of the Chevrolet Silverado EV, can use Tesla's charging network with Tesla's charging app and an adapter that fits between the Tesla plug and the EV's charge port receptacle.

Tesla also has a limited number of Magic Dock chargers that provide the adapter housed in a Tesla charger. GM and Ford will furnish adapters with their EVs before updating the on-vehicle plug receptacles. That will likely happen, Abuelsamid said, when current EVs get refreshed or replaced.

And that's when the bigger engineering and design changes will come.

"When the vehicles switch to the NACS port, you are going to revamp the wiring harness. Some wires won't be used, and others are going to be used differently," Abuelsamid said.

According to S&P Mobility, Tesla is operating more than 17,000 Superchargers and Destination Chargers in the United States. Tesla plans to open at least 3,500 Superchargers to other brands by the end of 2024 and increase the number of Level 2 charging docks to 4,000.

Tesla's NACS plug has five pins. The two large pins flow AC or DC current into the vehicle, depending on the type of charger. Tesla Superchargers dispense DC, while Tesla's Level 2 Destination Chargers dispense AC. Two smaller pins are used for communications between the car and the charger, and the third small pin is the ground wire.

The plug used in non-Tesla EVs — Combined Charging System — has seven pins in a different configuration. Two large upper pins are for AC current, three smaller pins are for communications and the ground wire, while in a separate lower section, two larger pins are for DC current.

The NACS plug uses a thinner charging cord and weighs about half of the CCS system used in North America.

Another big change that is likely being worked out between Tesla and the automakers switching to NACS is how to solve the accessibility problem.
On all Tesla vehicles, the charge port is on the left rear, which enables Tesla's nationwide charging network to use the same size parking spaces and same length charging cords. Tesla drivers back in and plug in the same way at every location. That consistency helps improve efficiency at Tesla charging stations.

Non-Tesla EVs with charge ports located anywhere but the left rear could cause problems at Tesla stations. Some vehicles need more than one space to get close enough for Tesla's short cords to reach the vehicle. Or, some vehicles have to be parked in a space and use the cord from the adjacent charger, which means other drivers can't use the adjacent charger.

Two things could change that: Tesla could agree to install longer charge cords to reach charge ports no matter where they are on the vehicle, or automakers could move the charge port to the left rear.

Moving the charge port, say from a grille or front fender to the left rear, would be a moderately complex undertaking. New or modified dies or a change in the manufacturing process would be needed to stamp fenders with charge port openings, and wiring would need to be rerouted, Al Kammerer, Jaguar's retired product development chief, told Automotive News.

GM and Ford would not comment on charge port locations and other issues related to the switch from CCS to NACS. The positions of the charge ports can vary from the front or rear of the vehicles or where a gasoline tank would be.

"What we can share at the moment is that adapters will be an important part of the transition to a single, unified charging standard," said GM spokesperson Natalee Runyan. "The plan is to make adapters available to GM EV customers in spring 2024, which will enable GM EVs with a CCS inlet to charge at Tesla Superchargers."

For that to happen for GM's models and other EVs, software that enables the charger to communicate or "handshake" with the vehicle, as well as a payment system, has to be established. Tesla chargers have no screen and no way for an EV driver to input information. Tesla's charging app for its Magic Dock handles that, but likely the software to handle the handshake will be part of a non-Tesla EV's operating system.

"The logical thing for Tesla to do, not that Tesla ever does anything logical, would be to create a software development kit for automakers that handles all of the communications requirements to enable vehicles to talk to their chargers," Abuelsamid of Guidehouse Insights said.

A charging expert at SAE International, which developed the J1172 standard for the CCS type plugs, agrees.

"If OEMs want to move toward a seamless, no-user-interaction charging experience, they must work to enable that functionality," said Christian Thiele, director of global ground vehicle standards at SAE. "The goal of implementing NACS should be that a user plugs in and walks away without looking back at the station."

It's not clear if non-Tesla EVs using Tesla's charging network will ever charge as consistently as the Model S, Model 3, Model X or Model Y, which use either a 7.7-kW or 11.5-kW onboard charger. The cars and chargers were designed to work as a system. The charging power varies on non-Tesla vehicles.

Some EVs from Porsche and Lucid, for example, can take electricity faster than a Tesla Supercharger can provide it.

Tesla has some learning to do, too. But what that entails is also unclear. Tesla, which does not respond to media inquiries, issued this statement after the Ford and GM charging deals were announced:

"It's always been our ambition to open the Supercharger network to non-Tesla EVs, and by doing so, encourage more drivers to go electric. More customers using the Supercharger network enables faster expansion.

"Our goal is to learn and iterate quickly, while continuing to aggressively expand the network, so we can eventually welcome both Tesla and non-Tesla drivers at every Supercharger worldwide."

Hannah Lutz contributed to this report.