One plug-in, fully understood
Two sessions today: one that started on plugging in, one that needed a card.
Both appear on the same invoice, under the same contract.
The questionCan you explain what happened in the second after plugging in?
The day in seven moments
Plugged in, no card: the car identifies the contract.
Stop 01Signal, data link, IP and TLS, services: a conversation over the cable.
Stop 02and from the car, the charger's own certificate first.
Stop 03Two roots, one : chains from different authorities accepted.
Stop 04A certificate update, carried by the charger from backend to car.
Stop 05Another operator: one condition missing, the card works instead.
Stop 06ISO 15118-20: bidirectional, wireless, megawatt charging.
Stop 07
Seven moments, one contract. moves the card into the car, and trust into certificates.
Where to go from here
Bidirectional charging follows ISO 15118-20 into the home and the grid, OCPI and roaming the contract between operator and provider, and OCPP in depth the backend side. See all learning paths.
Check your understanding
4 questions. Answer all of them to complete this stop. Each answer explains itself.
What did the car present at 11:20 AM?
The car presents the contract certificate and the eMAID for the provider's contract.
Why did the car trust the charger?
In the TLS connection, the charger proves itself with a certificate the car can check against its roots.
At 2:10 PM the card worked, Plug & Charge did not. What does that show?
The same contract worked by card, so the gap lay in the Plug & Charge chain at that operator.
What does ISO 15118-20 add that matters for the home charger?
ISO 15118-20 defines messages for energy flowing in both directions.
- Plug & Charge The car identifies itself with a certificate when plugged in, so no card or app is needed. EV charging fundamentals, stop 08 Glossary
- Contract certificate A certificate in the car that binds the driver's contract ID to a key only the car holds, used for Plug & Charge. Stop 03 Glossary
- eMAID The contract ID of an e-mobility contract, carried in the contract certificate for Plug & Charge. Stop 03 Glossary
- Trust list A list of root authorities that cars and chargers accept, so certificate chains from different authorities work together. Stop 04 Glossary