ISO 15118 is a standard for Vehicle to grid (V2G) communication interface that defines how extended communication between vehicle and charging station should take place. This is often assumed to include vehicle-to-grid power transfer, but this is not necessarily the case. See also What about V2G (vehicle-to-grid) power transfer?

• Due to the cryptographic requirements of ISO 15118, both the vehicle and the charging station must have the necessary hardware to support ISO 15118. It is not a capability that can be added via software.
• ISO 15118 hardware is built in to every Zaptec Pro charger.
• Zaptec Go does not support ISO 15118.

Plug & Charge

As the ISO 15118 communication interface allows for secure communication between the vehicle and the charging station, this makes it possible to identify the owner of the vehicle via the charging cable to start charging.

Plug & Charge uses multiple cryptographic mechanisms to ensure communication, and guarantees the confidentiality, integrity and authenticity of all exchanged transactions between the vehicle, charging station and payment operator.

This means that the owner of the vehicle does not need to use the SMS, App, RFID or NFC charge card to identify himself against the charging station to confirm his identity in order to start charging.

The EV, charging station and payment operator must support ISO 15118 with Plug & Charge. The systems and solutions to support this are developing rapidly; Zaptec will announce support for these systems as they become available.

State of Charge (SoC)

Because the ISO 15118 communication interface allows extended communication between the vehicle and the charging station, this makes it possible to read out the desired energy (in kWh) from the electric vehicle.

This allows the car to specify the desired energy (in kWh) for the charging session, based on the driver preferences. Both the vehicle and the charging station must support ISO 15118 with State of Charge. This feature is currently available on a limited number of cars. Support for this feature on Zaptec chargers is under consideration.

What about V2G (vehicle-to-grid) power transfer?

Some vehicles are able to transfer power using their AC port. These vehicles are able to power local appliances, but they cannot usually export power to the grid. This is because the regulations governing this are currently highly localised and vary between countries and grid operators. Any future support for AC power export to the grid will be governed by local legislation.