Why OCPP + ISO 15118 Integration Is Hard
ISO 15118 Plug and Charge works through a PKI certificate chain: the vehicle has a Contract Certificate from the eMSP, the SECC reads it during TLS handshake, the charger sends it to the CSMS via OCPP, the CSMS validates with the eMSP PKI, and charging begins automatically. This requires OCPP 2.0.1 with ISO 15118 Certificate Management extensions.
The Three Layers of OCPP + ISO 15118 Integration
Layer 1: Hardware (SECC + Charger CCU)
SECC must implement a full ISO 15118-2 stack with TLS 1.2/1.3, support certificate storage (up to 5 contract certificates on-board), and handle the complete EVCC-SECC session lifecycle including SupportedAppProtocol, Authorization, PowerDelivery, MeteringReceipt, and SessionStop messages.
Layer 2: OCPP Module
Key OCPP 2.0.1 messages for ISO 15118 PnC: Get15118EVCertificate (request contract certificate), CertificateSigned (CSMS delivers leaf certificate), InstallCertificate (PKI root CA management), Authorize (EMAID authorization), TransactionEvent (session data with ISO 15118 authorization).
Layer 3: CSMS Backend
The backend must support OCPP 2.0.1 Security Profile 3 (TLS + client certificate), integrate with eMobility PKI (Hubject, Mobi), handle contract certificate provisioning and rotation, and log signed meter values for billing.
Common Integration Problems and Fixes
| Problem | Root Cause | Fix |
|---|---|---|
| SECC authenticates but OCPP rejects | CSMS does not support OCPP 2.0.1 ISO 15118 messages | Upgrade CSMS to OCPP 2.0.1 with ISO 15118 extension |
| Certificate validation fails | Root CA not installed on charger | Use OCPP InstallCertificate to push eMobility root CA |
| TLS handshake fails | Mismatched TLS version or cipher suite | Align SECC TLS config with CSMS requirements |
Share Charging Integrated ISO 15118 + OCPP Solution
- SECC QC PLC Module: ISO 15118-2/20 + DIN 70121, TLS 1.2/1.3, EIM + PnC modes
- OCPP 2.0.1 Module: Full ISO 15118 certificate management message support
- Integration Support: CSMS connection guide and Hubject Plug and Charge documentation
- Validated with: Tesla, BMW, Hyundai, Volkswagen Group vehicles in European public charging networks
Start your ISO 15118 + OCPP integration: zhaishuoyun@share-charging.com | WhatsApp: +8615253120062
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How to integrate OCPP 2.0.1 with ISO 15118 Plug and Charge in your EV charging backend. Complete technical guide for EV charger manufacturers and CSMS developers.
