What Is OCPP? Charging Station Protocol and Versions
OCPP is the open protocol between a charger and its management software (CSMS).
What is OCPP, and what does it mean?
OCPP (Open Charge Point Protocol) is the open communication protocol between an electric vehicle charger and the central software (CSMS) that manages it. It is published by the Open Charge Alliance and is free to use. As long as the charger and the software speak the same OCPP version, chargers from different brands can be managed from a single panel.
In short, OCPP is the common language that lets a charger report "who is charging, how much energy I delivered, is there a fault" to the center, and lets the center send "start charging, stop, apply the tariff, update the software" to the charger.
What is OCPP used for?
- Registering the charger: When the charger powers on it announces itself to the center (BootNotification) and reports at set intervals that it is running (Heartbeat).
- User authorization: The identity coming from an RFID card or an app is verified at the center (Authorize).
- Charging session: The start and end of a session and the meter values are written to the center; billing is made from this record.
- Status and faults: Whether a connector is free, occupied or faulty is reported instantly (StatusNotification).
- Remote management: Starting and stopping charging remotely, restarting, changing settings and updating software are done from the center.
- Power limiting: The center limits the power delivered by sending a charging profile to the charger.
OCPP versions: the difference between 1.5, 1.6 and 2.0
- OCPP 1.5: An older version based on SOAP (XML). It is seen on older chargers still running in the field.
- OCPP 1.6: Alongside SOAP, it introduced the "1.6J" form that communicates in JSON over WebSocket. It is the version most widely used on chargers in the field.
- OCPP 2.0: The message structure was rebuilt: a charging session is tracked with a single transaction event (TransactionEvent), and device configuration and security were expanded. It is not backward compatible with 1.6; the software has to support the two versions separately.
After the 2.0 family, the Open Charge Alliance also published version 2.1. When buying a charger, what matters is not the newest version but the version the charger and the software both speak.
The difference between OCPP and OCPI
The two protocols connect different parties:
- OCPP: charger ↔ charging management software (CSMS).
- OCPI: CSMS ↔ another charging network or roaming platform. A driver of one network charging at another network's station, and the settlement between the two networks, are handled with this protocol.
- ISO 15118: vehicle ↔ charger. It is not a protocol of the management software.
We explained what a CSMS is and how it differs from a CPO in the CSMS nedir article.
What to check for OCPP when buying a charger
- Does the device's technical datasheet state which OCPP version it supports (1.6J, 2.0)?
- Can you enter the center address yourself, or is the charger locked to the manufacturer's own system?
- Can the manufacturer document that it has passed the Open Charge Alliance compliance test?
- Can software updates be done remotely, over OCPP?
If you buy a charger that does not support OCPP, you cannot change the management software later; you stay tied to the charger manufacturer's system.
Which OCPP versions does SmartŞarj support?
SmartŞarj communicates with chargers using OCPP 1.5, 1.6 and 2.0, and with other charging networks and roaming platforms using OCPI 2.2.1. This way, AC and DC chargers that speak OCPP are managed from the same panel, whatever their brand. For details of the software see the charging management software page, and for hardware the AC and DC chargers page.
