EV charging: from connection to billable service

At first glance, charging an electric car is a simple process: the vehicle is connected, charging starts and then ends at some point. However, from an operator's point of view, each charge is a longer chain of events. It is necessary to know which equipment is available, who initiated the operation, how much energy was transferred, and what should be the place of the result in the accounting or company process.

The standard connection reduces manufacturer constraints

OCPP 1.6-J is a widely used communication protocol between charging equipment and central monitoring systems. It provides standard messages for status reporting, charging transactions, metrics, identification, and certain remote operations, among others.

Support of the standard alone does not guarantee full interoperability. Manufacturer implementations, configurations and supported functions may differ, so it is worth including each new charger type with a verified compatibility test.

The connection follows the entire charging life cycle

Communication between the charger and the management side is not a single short query. The device logs in, regularly reports status, handles the identification request, indicates the start of the transaction, sends measurement data, and then closes the process. The platform should interpret this as a connected lifecycle.

The integration layer protects the business system from protocol details

A well-defined edge or integration layer can transform the charger's standard messages into unified events for the enterprise platform. Thus, billing, energy monitoring or customer management do not need to know all the details of the charging protocol.

The responsibilities of the two sides can be clearly separated: the protocol layer ensures the connection and the correct handling of messages, while the business platform manages the authorization, tariff, reservation, billing and allocation and reporting. This cast makes it easy to expand later and include devices from different manufacturers.

An orderly state is required even in the event of a network failure

The connection between the charging location and the central platform may be interrupted periodically. For safe operation, it is necessary to determine in advance whether a new charge can be started in this case, how identification is carried out, which data is stored locally, and how it is transmitted after the connection is restored.

The goal is not just to avoid data loss. The sequence, time stamps and measurement chain of the transaction must also remain verifiable, especially if the data is used as a basis for billing and allocation.

Identification and Authorization

RFID or other identification methods are only the first step. The system must link the identifier with the right of use, the customer or organization, the applicable tariff and any restrictions. The response must be fast while the authorization decision remains loggable and traceable.

The charger is part of the energy system

The simultaneous operation of several chargers can cause significant on-site power demand. EV charging cannot therefore be separated from energy monitoring. The available capacity, other consumers of the building, local production and energy storage can together determine how much power can be distributed safely.

The goal of intelligent power distribution is not simply limitation, but better utilization of site capacity, while user needs and operational priorities are also enforced.

Decision Checklist

• Which OCPP version and function range does the charger actually support?
• How is the charging transaction related to the user and the tariff?
• What happens in case of communication failure or restart?
• Will the order and traceability of the measurement data remain?
• Is protocol management separated from business and accounting logic?
• How does charging fit into the site's performance management?
• Is the integration of the new charger type documented and tested?