ISO 15118 vs DIN SPEC 70121. What is the difference?

One of the most frequent questions I get in members of the EV community is the difference among ISO 15118 and DIN SPEC 70121. The answer is likely to leave many very surprised. This is a key difference to know in order to ensure your products are compatible. This German technological specification DIN 70121 is based on an early unpublished variant of ISO 15118 standard and defines digital communication between electric vehicles and DC charging stations. DC is a shorthand for direct current, which means that DIN SPEC 70121 only covers DC charging mode, DC charging mode, whereas ISO 15118 covers both AC (alternating current) and DC charging modes.

It is believed that the ISO 15118 series has grown significantly since the initial release of DIN SPEC 70121 and this has resulted in a myriad of technical variations among DIN SPEC 70121 and ISO 15118. DIN SPEC was first released in 2012 and then updated in 2014. The initial version of the specification for ISO 15118 was released in 2014, and the version 2 is currently in development.

It’s similar to a dialect of one of the languages. If you don’t know the dialect, then it doesn’t matter if the dialect is the identical language or not: it’s impossible to continue the conversation.

This means that a charge station that can only support ISO 15118 cannot charge an EV that is only speaking DIN SPEC 70121. However, if the EV is able to communicate in both dialects, they can enter an charging session and reverse. This is why it’s important to be aware of and apply this information to your product line as well as future developments.

Another major difference in ISO 15118 and DIN SPEC 70121 is that the former doesn’t support Plug & Charge, meaning there is no secure communication using Transport Layer Security (TLS) as well as no digital certificates and no digital signatures based on XML, therefore data integrity and authenticity can’t be assured. Additionally, no smart chargingis feasible with DIN SPEC 70121, meaning that you cannot transmit charging schedules to your electric vehicle to charge it in an smarter, more efficient grid-friendly method.

DIN SPEC 70121 was created in order to make the market operating prior to when ISO 15118 was released. However, it is still used in various test installations during ISO 15118 Testing Symposia. ISO 15118 Testing Symposia (Video 1 from my online course ” Revolutionize Electric Vehicle Charging” contains images of the latest symposia). But the days of DIN SPEC are over, and ISO 15118 and its wide array of features are fast become the norm in the market.

We’ll explore this vital distinction in our online course Learn the Art of Communication for charging electric vehicles. Please get in touch with me If you have any further questions or require clarification.