August 21, 2023
The Open Charge Point Protocol, often shortened to OCPP, is a vital component in the infrastructure of electric vehicle (EV) charging.
As a universal protocol, OCPP makes seamless communication possible between different EV charging stations and their corresponding backend system software. This compatibility feature enables a wide array of charging stations and systems to interact and cooperate effectively.
The benefits of implementing OCPP are vast and have a big impact on EV charging. OCPP adoption:
This environment of continuous improvement directly contributes to advancements in technology and service quality. The end result? A hassle-free and streamlined experience for users of electric vehicles and fleet managers.
In this article, our focus will be on the practical facets of OCPP, particularly in relation to testing and identifying potential issues in EV charging systems.
We look into common issues and problems, their solutions, and key operational elements such as boot notifications, heartbeat, and authorization requests. Learn more about OCPP and smart charging in our OCPP Report.
The Open Charge Point Protocol (OCPP) is a standardized communication framework widely utilized in the Electric Vehicle Supply Equipment (EVSE) industry. This protocol allows different hardware and software systems to communicate efficiently, making it the lingua franca of the EV charging environment.
The OCPP operates like a shared language, ensuring both the sending and receiving ends understand the information being communicated. This protocol, like any language, has rules and structures that guide the communication process, ensuring mutual understanding and efficient information transfer.
The protocol employs a mechanism called a Websocket to facilitate this communication between the hardware (the charger) and the backend system (the EV charging network software). This connection is initiated by the hardware, which sends specific information, including a secret and a charger ID, to the backend system.
The backend system validates this information and completes the handshake, accepting the connection. Once this connection is established, messages can be sent and received by both the client end and the backend.
In case of disconnection, either intentionally or accidentally, both sides can reconnect, ensuring a flexible and resilient communication system. The entire connection process requires just a single URL, the Websocket URL.
Depending on the hardware manufacturer, there are several ways to update this Websocket URL. The update could be done remotely via an app, locally via a TCP connection, or by sending the URL to the hardware manufacturer's backend for updating. Some manufacturers may even allow direct access to their system for URL updates.
Smart charging software system Ampcontrol has a simple three-step process to connect your charger with a URL.
The importance of EV charging hardware testing lies in its ability to identify potential faults and ensure the compatibility of charging stations before they are fully operational, thus guaranteeing an efficient and reliable charging experience for EV users.
During the process of onsite testing for EV chargers, maintaining stable connectivity is crucial. A continuous communication between the EV charger and the backend system allows for smooth operations and efficient charging. One of the vital elements of this connectivity is the 'heartbeat' function within the OCPP acting as a lifeline for the network.
The heartbeat function is essentially the periodic message sent from the EV charger to the backend system, indicating the charger's online status. It establishes that the charger is active, functioning correctly, and ready to exchange messages. This process is continuous and is run at set intervals, ensuring real-time updates of the charger's status. Any interruption in the heartbeat can signal a potential issue with the charger or the network, making it a fundamental tool for identifying connectivity issues.
Despite the importance of a stable heartbeat, connection issues can still occur during onsite testing. One of the most common problems involves the incorrect configuration of Charger IDs or serial numbers. These unique identifiers are essential for distinguishing chargers in the network, and any discrepancy can result in connection errors. These identifiers must be correctly set during the initial charger configuration and verified before starting the test procedures.
Another common issue is the lack of Transport Layer Security (TLS), which protects the data being transmitted over the network. Without TLS, data can be intercepted, leading to potential unauthorized access or tampering. Incorporating TLS into the OCPP testing process ensures that the data exchanged between the charger and backend system is secure, maintaining the integrity of the testing procedures.
Timely troubleshooting of these issues is necessary to avoid disruptions in the testing process. Effective troubleshooting strategies involve verifying the charger IDs or serial numbers, ensuring the heartbeat is functioning correctly, and checking that TLS has been appropriately incorporated.
Another connection challenge could be high latency, which could disrupt synchronization and affect the real-time monitoring of charge sessions. Instances of latency up to five minutes have been reported, which can severely impact operations if left unchecked.
Setting up chargers correctly is key to efficient, user-friendly operations. This involves a host of considerations, including power parameters, charger type identification, authorisation requests, and authentication methods.
An essential aspect of testing OCPP chargers involves understanding power profiles. These are crucial configurations that decide how chargers interpret power and current information from an EV.
Power profiles allow the charging station to communicate with the vehicle's onboard charging system, ensuring the flow of electricity aligns with the vehicle's capabilities and charging needs.
The power profile is defined by transaction meter values. These values establish the rate at which energy is transferred during a charging session. It's essential to ensure these meter values are correctly configured according to the EV's specifications and the capacity of the charging station. If they are misconfigured, the charger may deliver too much or too little power, leading to longer charging times or, worse, potential harm to the vehicle's battery.
Correctly configuring transaction meter values allows the charger to operate smoothly, providing a seamless charging experience for the user. Accurate power profiles prevent possible discrepancies or disruptions in the charging process, promoting reliable and efficient EV charging.
Default profiles, an inherent aspect of an OCPP charger, dictate how the charger behaves under standard conditions. These profiles encompass parameters like maximum power delivery, response to charging requests, and idle behavior. They are designed to match the charger's capabilities with the typical requirements of EVs it is likely to service.
Understanding the standard behavior of these default profiles is crucial to ensure that they perform optimally during charging sessions. A misinterpretation of the behavior of default profiles can lead to erroneous operations, affecting the charger's performance, or worse, causing a fault in the system. This can be detrimental, especially in a public charging environment where a wide variety of EVs might rely on these default profiles for their charging needs.
Some common misconceptions about default profiles include the belief that they can't be altered or that they represent the maximum capabilities of the charger. In reality, these profiles can often be configured to better serve the requirements of specific EV models or charging environments.
Testing OCPP chargers is a crucial element in the smooth operation of EV charging systems. A thorough understanding of the OCPP and its intricacies significantly contributes to the accuracy and efficiency of these tests, leading to better-performing charging stations.
This guide aimed to shed light on various aspects of OCPP charger testing, from setting up onsite tests to understanding power profiles and common errors. It highlighted the importance of stable connectivity, proper charger configuration, and an in-depth understanding of default and power profiles.
We hope that the insights shared in this guide will prove valuable in enhancing your own testing processes. By embracing the principles outlined here, you can strive towards more accurate and efficient testing of OCPP chargers, ultimately contributing to the broader goal of effective and reliable EV charging infrastructure.
Ampcontrol is a leading smart charging software system that makes it easy to manage your EV charging and run extensive tests on OCPP chargers. To find out more, contact us today to book a demo.
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