How to choose the OCPP protocol for the control board of a 22KW AC charging pile?

When selecting the OCPP protocol version for the control board of a 22KW AC charging pile, the core considerations lie in the compatibility of the operation platform, functional requirements, and deployment scenarios. The following are key decision-making points:

Current status of protocol version

• OCPP 1.6 remains the mainstream in China, and is preferred by the vast majority of third-party operation platforms (such as Teclast, Xingxing Charging, Yunkuai Fast Charging, etc.). If the pile owner intends to integrate with these platforms, OCPP 1.6 is a safe choice due to its mature technology, short integration cycle, and low debugging cost.

• OCPP 2.0.1 represents an international trend, introducing capabilities such as Plug and Charge (PnC), intelligent charging scheduling, device management, and a security certificate system. It is a must-have for overseas exports or high-end stations, and domestic platforms are gradually adapting to it but it has not yet become widespread.

• OCPP 2.1 has just been released, and there are almost no actual deployment cases in China. It is not recommended to choose it at this stage.

Special considerations for 22KW piles

22KW AC charging piles are mostly equipped with three-phase 380V input and a current of about 32A. They are commonly found in commercial parking lots, office buildings, hotels, and other scenarios, and have specific requirements for protocol functions:

• Intelligent Load Management: When multiple piles are connected in parallel, the LoadManagement function of OCPP 2.0.1 can dynamically allocate power to avoid transformer overload. Version 1.6 requires reliance on the platform side or local controller for implementation, resulting in poor real-time performance.

• Plug and Charge (PnC): In high-end commercial scenarios, users pursue seamless charging experiences. OCPP 2.0.1 natively supports ISO 15118 PnC, while 1.6 requires additional development or relies on RFID/APP workarounds.

• Firmware Over-The-Air (FOTA): The deployment of 22KW piles is scattered, leading to high on-site maintenance costs. The FirmwareManagement in OCPP 2.0.1 is more comprehensive, supporting resume from a broken point and signature verification. Although 1.6 supports these features, its functionality is relatively basic.

• Transaction settlement security: OCPP 2.0.1 mandates the use of TLS 1.2+ certificate system to prevent man-in-the-middle attacks that tamper with billing data. Version 1.6 is optional, and most domestic platforms do not enforce its use.

Decision-making path

• Scenarios for choosing OCPP 1.6: Domestic operation platform is the main focus, budget is sensitive, rapid launch, no rigid demand for PnC, and the platform does not support 2.0.1 yet.

• Scenarios for selecting OCPP 2.0.1: overseas exports, high-end commercial stations, requiring intelligent load balancing, platforms already compatible with 2.0.1, high requirements for security and compliance, and having PnC planning.

• Compromise solution: Reserve 2.0.1 capabilities (such as security chips, large-capacity Flash) for the control board hardware, run the software at version 1.6 initially, and perform OTA upgrades after the platform matures. This solution increases initial costs by about 15%-20%, but avoids hardware replacement in the later stages.

Key points for control panel selection

• Communication module: 4G/Cat.1 is the standard configuration, and eSIM support is required for overseas use; WiFi/Ethernet serves as a supplement for local area network deployment.

• Secure chip: If planning for version 2.0.1, a secure element supporting ECC/RSA needs to be pre-installed for certificate storage and TLS handshake.

• Processor performance: The 2.0.1 protocol stack is more complex. It is recommended to use a main control MCU with ≥256KB Flash and ≥64KB RAM to avoid potential computing power bottlenecks in the future.

• Protocol stack maturity: Preferentially choose protocol stack implementations that have been officially certified by OCA (Open Charge Alliance) to reduce interoperability risks.

Risk statement

• Some platforms claim to support OCPP 2.0.1, but in reality, they only implement a subset of core functions, lacking features such as smart charging and PnC. It is essential to request a platform compatibility test report before integration.

• There are some semantic differences between the domestic GB/T 18487.1-2024 and OCPP (such as start-up methods and fault code mappings). The control board requires an adaptation layer conversion and cannot be directly translated.

• The certificate management of OCPP 2.0.1 imposes high requirements on operation and maintenance personnel. If certificates expire and are not renewed, it will result in the entire batch of piles going offline, necessitating the establishment of an automated monitoring mechanism.

It is recommended to confirm with the target operation platform its OCPP version support roadmap to avoid mismatch between the control board protocol version and platform capabilities, which may lead to functional limitations or redundant development.

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