What is OCPP?
OCPP stands for Open Charge Point Protocol and standardises communication between charging stations and a central charging management platform, also known as a charging backend or Charging Station Management System (CSMS). The open protocol connects charging hardware and management software from different providers. It supports monitoring, operational management and the transmission of charging limits.
OCPP at a Glance
• OCPP enables charging stations and a CSMS to exchange operational data and control commands.
• Smart Charging allows time-dependent current or power limits for charging.
• Available functions depend on the OCPP version and its implementation in the charging station and CSMS.
How Does Communication via OCPP Work?
Charging stations report information such as availability, fault conditions, meter readings, charging power and individual charging sessions to the CSMS. The CSMS processes this data and can authorise users, remotely start or stop charging sessions, and manage configurations and firmware updates.
OCPP 1.6J and OCPP 2.x exchange structured JSON messages over WebSocket connections. The CSMS can run locally or in the cloud; OCPP does not inherently require a cloud service.
For Smart Charging, the CSMS transmits charging profiles that specify permitted current or power levels over defined periods. These limits do not guarantee a particular charging power: the vehicle, charging station and other operating constraints determine the actual power drawn.
For example, a site EMS can calculate the power available for charging based on grid imports, photovoltaic generation and other loads. A connected CSMS distributes this power budget across charging points and transmits the corresponding charging profiles via OCPP. The connection between the EMS and CSMS requires a suitable additional interface. An OCPP-capable charging station is therefore not automatically compatible with every EMS.
Measurement feedback allows the system to check the effect of its commands and adjust them. The optimisation logic resides in the EMS or CSMS; OCPP provides the communication. This separation is one possible architecture: EMS and CSMS functions can also be combined in a single system.
Where Is OCPP Used?
• Charging site operation: Operators centrally monitor charging stations from different manufacturers and remotely address faults or configuration changes.
• Dynamic load management: Charging limits are adjusted to the available connection capacity and the consumption of other equipment.
• Solar- and price-based charging: An EMS or CSMS schedules charging based on available solar energy, electricity prices and operational requirements. OCPP transmits the resulting instructions.
Which Versions and Requirements Matter?
OCPP makes it easier to combine charging hardware and management software from different providers. The versions differ in the following key areas.
Version Key characteristics
OCPP 1.6 Already supports Smart Charging and charging profiles; available as the JSON variant OCPP 1.6J.
OCPP 2.0.1 Expands device management, security and charging functions; not directly compatible with OCPP 1.6.
OCPP 2.1 Adds functions particularly for bidirectional charging and the integration of distributed energy resources.
A shared protocol version alone does not guarantee that all required functions work together. For OCPP 1.6 charging stations, it is particularly important to check whether Smart Charging is supported and, where applicable, covered by the certification scope: this functionality is optional in OCPP 1.6 certification for charging stations.
Implementation also requires checking the available measurements, supported charging profiles and actual enforcement of charging limits. Security functions such as encrypted connections and authentication must be coordinated between the components.
For load management, measurement intervals, communication delays and charging station response times are critical. Suitable fallback limits and their validity must be defined for connection failures. Cloud-based charging limits do not replace local electrical protection.
This new protocol covers the connection between the charging station and CSMS. Communication between the vehicle and charging station is governed by other standards, such as ISO 15118.
How Can Charging Infrastructure Be Coordinated with EcoPhi?
The EcoPhi EMSsupports site-level control of photovoltaic systems, battery storage and compatible loads. If charging infrastructure is to be included, the available device interfaces and control functions must be assessed for the specific project.
This includes checking which measurements are available, whether charging power budgets can be calculated and transmitted, and which connections to charging stations or an existing CSMS are available. A direct OCPP connection cannot be assumed solely because the charging stations support OCPP. Additional integration work may be required depending on the project.
Energy coordination also does not mean that EcoPhi handles user management, payment processing or every function of a charging backend. Separate systems may still be required for these tasks.
In Summary
OCPP makes it easier to operate charging stations from different manufacturers within a shared system. Reliable load management requires the necessary measurements and charging functions, coordinated response times and defined fallback rules. Integration with a site EMS also requires a suitable system interface.
Frequently Asked Questions About OCPP
Can an OCPP Charging Station Operate Without Internet Access?
Yes, if the CSMS is accessible locally. If the connection to the CSMS is also lost, continued operation depends on locally stored authorisations, charging profiles and device configuration.
Does OCPP Automatically Provide the Vehicle’s State of Charge?
No. The state of charge must first be available to the charging station, which must then be able to transmit it to the CSMS. OCPP support alone does not guarantee this measurement.
Does OCPP 2.1 Automatically Enable Bidirectional Charging?
No. In addition to protocol support, the vehicle, charging station and electrical installation must be suitable for reverse power flow.