Short answer
ISO 15118 and DIN SPEC 70121 are vehicle-to-charger communication standards. OCPP is charger-to-backend communication. For a commercial buyer, this means ISO 15118 or DIN SPEC 70121 affects the EV-to-EVSE charging session, while OCPP and CSMS affect remote monitoring, users, billing, tariffs, firmware, reporting and CPO operation.
Where ISO 15118, DIN 70121 and OCPP sit in the charging stack
Many RFQs mix ISO 15118, DIN SPEC 70121, OCPP and CSMS in the same sentence. They are related, but they answer different questions. If the project team does not separate these layers, the charger may match the vehicle but fail backend operation, or connect to a backend while missing the vehicle communication feature required by the tender.
| Layer | Protocol or system | What it connects | Buyer question |
|---|---|---|---|
| Vehicle to charger | DIN SPEC 70121 | EV and DC charging station for basic CCS DC communication. | Is the charger compatible with the target CCS vehicle fleet? |
| Vehicle to charger | ISO 15118-2 / ISO 15118-20 | EV and EVSE for advanced V2G communication, Plug and Charge and smart charging roadmap functions. | Does the project require Plug and Charge, V2G or ISO 15118 tender language? |
| Charger to backend | OCPP 1.6J / OCPP 2.0.1 | Charger and charging station management system. | Can the charger connect to the target CSMS and pass operating tests? |
| Operation software | CSMS / CPO platform | Sites, chargers, users, pricing, payments, alerts and reports. | Can the operator run the charging business after installation? |
DIN SPEC 70121 in commercial DC charging
DIN SPEC 70121 is usually discussed with earlier CCS DC fast charging communication. It helps the EV and DC charger exchange the information needed for a controlled DC charging session. For many basic CCS DC charging projects, the buyer does not need to request a full Plug and Charge ecosystem; they need to confirm vehicle compatibility, connector type, charger firmware, current/voltage range and backend operation.
DIN SPEC 70121 is still relevant in RFQs because many vehicles and chargers in the field rely on CCS basic communication. A buyer should not reject DIN 70121 language automatically, but should check whether the tender or vehicle fleet actually needs ISO 15118 functions.
ISO 15118 for Plug and Charge, smart charging and V2G roadmap
ISO 15118 is the more advanced vehicle-to-grid communication family. ISO states that ISO 15118-20:2022 specifies communication between the EV and EVSE and includes requirements for bidirectional power transfer. In commercial buying terms, ISO 15118 becomes important when the project asks for Plug and Charge, certificate-based authorization, bidirectional charging, more advanced smart charging or strict tender compliance.
Do not treat "ISO 15118 supported" as a single yes/no label. Ask which part is supported, which charger model and firmware are included, whether Plug and Charge PKI is in scope, and whether interoperability testing is required by the project.
Plug and Charge is not only a charger feature
Plug and Charge lets a vehicle authenticate and start a charging session without a separate RFID card, payment terminal or app step. CharIN describes Plug and Charge as automated communication and billing between the EV and charging station, with ISO 15118 defining the needed interfaces. For buyers, the important point is that Plug and Charge is an ecosystem decision, not just a checkbox on a charger datasheet.
| Scope item | What to confirm | Why it matters |
|---|---|---|
| Vehicle support | Target vehicle models, ISO 15118 feature set and market rollout. | Plug and Charge cannot work if the vehicle side is not ready. |
| Charger support | Exact charger model, controller, firmware and certificate handling. | Different SKUs may have different protocol and security support. |
| Backend support | CSMS, payment account, PKI workflow and operator responsibility. | Authentication and billing require backend participation. |
| Testing | Interoperability test, pilot vehicle test and acceptance evidence. | Reduces field risk before a public or fleet rollout. |
ISO 15118 vs OCPP 2.0.1
OCPP 2.0.1 is often mentioned near ISO 15118 because newer commercial networks want better security, device management and future-ready smart charging workflows. But OCPP does not replace ISO 15118. OCPP connects the charger to the backend; ISO 15118 connects the vehicle to the charger. A commercial project may need both, but for different reasons.
If your RFQ says "OCPP 2.0.1 with ISO 15118 support", ask the supplier to separate the response into vehicle communication, charger firmware, security profile, backend connection and acceptance testing.
RFQ checklist for ISO 15118 or DIN 70121 projects
| RFQ item | What to send | What SUNFULL should confirm |
|---|---|---|
| Vehicle and market | Country, vehicle brands, connector standard, battery voltage range and tender wording. | Whether DIN 70121, ISO 15118 or both should be considered. |
| Charger type | AC wallbox, DC fast charger, 150kW highway charger, fleet depot charger or V2G charger. | Which product family and firmware scope fits the requirement. |
| Authorization method | RFID, app, QR, POS, free charging, fleet card or Plug and Charge. | Whether ISO 15118 certificate-based authorization is required. |
| Backend platform | Target CSMS, OCPP version, security profile, test account and payment workflow. | How charger-to-backend testing will be handled. |
| Evidence needed | Datasheet, protocol note, remote demo, test log, certificate or pilot test plan. | Which documents can be prepared before sample or batch order. |
Procurement warning
Do not buy only from protocol keywords. A charger can list CCS, ISO 15118, DIN 70121 and OCPP but still need a model-specific check. Confirm connector type, vehicle compatibility, firmware version, backend platform and acceptance test before placing a batch order.
Best-fit SUNFULL pages by intent
If the buyer is researching ISO 15118 or DIN SPEC 70121 because of a tender, start with the protocol checklist. If the buyer is actually asking about software operation, move them to the OCPP or CSMS pages. If they are deciding hardware, move them to DC fast charger or commercial charger pages.
| Buyer intent | Best next page | Why |
|---|---|---|
| OCPP 2.0.1, backend testing, CPO software | OCPP / CSMS platform | Converts protocol research into software and charger RFQ scope. |
| Fleet charging management, depot software | Fleet charging management | Matches fleet scheduling, load management and CPO software intent. |
| Commercial charger procurement | Commercial EV charger manufacturer | Connects protocol needs to AC/DC charger selection and quote details. |
| DC fast charger hardware | DC fast charger | Lets buyers compare power, connector and site use cases. |
| Highway 150kW charger | 150kW DC fast charger | Supports high-impression 150kW search demand and highway RFQs. |
Standards references
For standards language, use official sources first: ISO 15118-20:2022, CharIN CCS basic technical details and CharIN Plug and Charge overview. For procurement, still verify the exact charger model, firmware and backend workflow with the supplier.
FAQ
What is ISO 15118 in EV charging?
ISO 15118 is the vehicle-to-grid communication standard used between the electric vehicle and EVSE. It supports advanced communication such as Plug and Charge, smart charging and bidirectional charging roadmap functions.
What is DIN SPEC 70121?
DIN SPEC 70121 is an earlier CCS DC charging communication specification used for digital communication between a DC charging station and an electric vehicle, mainly for basic DC charging control with external identification.
Is ISO 15118 the same as OCPP?
No. ISO 15118 and DIN SPEC 70121 are used between the vehicle and charger. OCPP is used between the charger and the CSMS or backend platform.
Do all commercial DC chargers need Plug and Charge?
No. Many commercial DC charging projects still use RFID, app, QR or POS authorization. Plug and Charge is useful when the project, vehicle fleet and backend ecosystem require ISO 15118 certificate-based authorization.
Related SUNFULL pages
Need ISO 15118, DIN 70121 or OCPP checked before quotation?
Send the target country, vehicle model, connector standard, charger power, OCPP backend, authorization method and tender wording. SUNFULL can help separate vehicle protocol requirements from CSMS operation scope.