ISO 15118-20, V2G and OCPP Readiness: A Practical Protocol Guide for MIDA OEM/ODM Partners

Quick Answer

“Protocol ready” is the difference between a charger that ships and a charger that gets rejected at commissioning. Three standards dominate the decision: ISO 15118-20 governs high-level communication, Plug and Charge and bidirectional services; OCPP 1.6/2.0 governs the charger-to-backend link; and the connector layer is defined by IEC 62196. In 2026, ISO 15118-20 Amendment 1 integrated the Megawatt Charging System, added new AC Distributed Energy Resources services, and strengthened the security architecture. For MIDA OEM/ODM partners, readiness therefore means selecting the right module and connector variants — including V2G modules from 20 kW to 45 kW — and documenting the exact protocol profiles implemented.

Key Takeaways

• Amendment 1 changed the scope. Published on 17 July 2026, it added dedicated MCS communication procedures, new AC DER services supporting bidirectional interaction, and a stronger security architecture.
• V2G is legal but not yet plug-and-play. The IEA reports 22 models with V2G capabilities today — under 1.5% of all EV models — and notes that multiparty interoperability between chargers and EVs remains extremely low.
• Regulation is moving ahead of deployment. The European Union has defined minimum requirements for all new chargers from 2027, including bidirectional capability and ISO 15118-20 support.
• Module choice determines V2G capability. MIDA’s V2G power modules span 20 kW to 45 kW, and bidirectional AC-DC modules span 20 kW to 62.5 kW, alongside conventional DC modules from 20 kW to 60 kW.
• OCPP is the commercial layer. OCPP 1.6 and 2.0 support is available across MIDA’s DC charging range, which is what allows a charger to be integrated into an operator’s existing management platform.

The protocol layer is where most cross-border charging projects stall. A charger can meet every electrical specification and still fail to operate in a target market because the vehicle-to-charger handshake profile is not implemented, the backend protocol version is mismatched, or the certification evidence does not match what the regulator requires. MIDA’s own published commentary on European shipments frames ISO 15118 as a “mandatory question” for charging stations — which is precisely the right framing for OEM/ODM partners: it is a question that must be answered before the order confirmation, not after the container arrives.

What Changed in 2026: ISO 15118-20 Amendment 1

ISO 15118-20 was originally published in 2022 and defines the fully standardized bidirectional communication pathway for the Combined Charging System. Amendment 1, published on 17 July 2026, extended it in three directions:

1. Megawatt Charging System integration. The amendment introduces dedicated communication procedures and requirements for MCS, enabling standardized high-power charging communication for heavy-duty vehicles and other megawatt-scale applications.
2. New AC Distributed Energy Resources services. These extensions strengthen bidirectional energy interaction between electric vehicles and the grid, supporting advanced smart charging and energy management use cases.
3. Enhanced security architecture. The amendment provides a more robust foundation for secure EV charging communication.

CharIN’s contribution is noteworthy for OEM/ODM planning: the association’s experts participated in international standardization activities, and feedback gathered through members, interoperability testing and early MCS implementation work helped validate practical communication requirements. In other words, the amendment reflects field implementation experience rather than purely theoretical specification work — which usually means fewer surprises at conformance testing.

The Protocol Stack a Modern Charger Must Carry

A production-grade charger implements several layers simultaneously. The table below maps them to the decisions an OEM/ODM programme must make.

Two clarifications matter for planning. First, communication in CCS is based on PLC using HomePlug Green PHY technology, not CAN bus or RS-485 — a vehicle and charger must share the same communication approach to complete a session. Second, CCS uses TLS secure communication, which enables encryption and authentication for secured payments, Plug and Charge, and commercial use of V2G in energy balancing markets. TLS is therefore not an optional add-on for V2G programmes; it is a prerequisite.

V2G Reality Check: Strong Standards, Fragmented Implementation

Vehicle-to-grid is the clearest case where the standard exists but the ecosystem does not yet follow uniformly. The IEA’s Vehicle-to-grid technology report provides the calibration an OEM/ODM partner needs before committing roadmap budget:

• 22 models have V2G capabilities today, accounting for less than 1.5% of all EV models. When all bidirectional capabilities are counted — including V2H and V2L — the figure is at least three times higher.
• Early V2G deployments were based on CHAdeMO. Among current ecosystems, only CCS, via ISO 15118-20, defines a fully standardized V2G communication pathway. GB/T supports V2G mainly through partial, system-integrated implementations, and NACS V2G capabilities are not yet fully specified.
• Interoperability is currently extremely low. All commercial V2G offerings today are packages combining specific EV models, specific chargers, and a tariff from a specific utility — not open multi-vendor configurations.
• Test procedures to ensure conformity with ISO 15118-20 and multiparty interoperability across EV and charger brands are still under development, notably through the IEA’s Electric Vehicles Technology Collaboration Programme Task 53.

The practical implication is that a V2G-capable charger is a platform investment, not a near-term revenue product for most sites. The hardware should be capable; the commercial configuration will follow the market.

What “Protocol Ready” Means for an OEM/ODM Programme

Readiness is best broken into three deliverables.

Hardware layer

Select modules and connectors that support the target capability without over-specifying. The MIDA module portfolio spans conventional DC modules from 20 kW to 60 kW, liquid-cooled modules from 40 kW to 125 kW, bidirectional AC-DC modules from 20 kW to 62.5 kW, and V2G modules from 20 kW to 45 kW. Connector variants span CCS1 (80–500 A), CCS2 (125–1,000 A), CHAdeMO (125–300 A), GB/T (200–1,000 A) and NACS (250–600 A).

A frequent error is pairing a V2G-capable module with a connector and controller that cannot support the bidirectional profile. The module is necessary but not sufficient.

Software layer

Confirm three things in writing:

1. Which ISO 15118 profile set is implemented (for example, which of the AC DER services from Amendment 1 are supported, and under what conditions).
2. Which OCPP version the charger ships with, and whether the smart-charging profile needed for load management is covered.
3. Certificate lifecycle management — how TLS certificates are provisioned, rotated and revoked in the field.

For reference, MIDA’s commercial DC charging piles support OCPP 1.6 and 2.0 alongside CCS, GB/T, NACS and CHAdeMO connectors, which means an operator can deploy the same platform across markets with different protocol requirements.

Documentation layer

Conformance evidence is a deliverable, not paperwork. It should include a protocol implementation statement, the tested firmware version, the test tool and version used, and a clear statement of which features were validated and which were not. Where the electrified liquid-cooled HPC connector or split DC architecture is used, the documentation should cover the full power path, not only the communication controller.

V2G Economics: Scenario Assumptions, Not Guarantees

V2G revenue is frequently quoted without context. The IEA’s published ranges are the appropriate reference, and every figure below should be treated as an illustrative scenario assumption, not a MIDA result or a promised return.

The IEA also notes that well-managed V2G can reduce capacity loss compared with unmanaged charging, because average state-of-charge is normally lower — but that OEMs mitigate warranty risk by limiting energy throughput or restricting V2G to approved chargers. Any V2G business case must reconcile the revenue assumption with the warranty terms of the specific vehicle fleet.

Regulatory Timeline Buyers Should Track

Frequently Asked Questions

1. What is the difference between ISO 15118-2 and ISO 15118-20? ISO 15118-2 is the earlier high-level communication standard for CCS. ISO 15118-20, published in 2022 and amended in 2026, extends it to support bidirectional services and, through Amendment 1, the Megawatt Charging System plus new AC Distributed Energy Resources services. V2G was not part of ISO 15118-2 and was added only later.

2. What does OCPP do that ISO 15118 does not? ISO 15118 governs communication between the vehicle and the charger. OCPP governs communication between the charger and the charging station management system — authorisation, tariffs, smart charging schedules and remote diagnostics. A production site needs both.

3. Can a charger be V2G-ready without being V2G-certified? Hardware can be designed to support bidirectional operation while certification for a specific grid code is still pending. Buyers should insist that “ready” is defined precisely: which module, which connector, which firmware, and which grid codes have been validated.

4. Why does TLS matter for V2G? CCS uses TLS for encryption and authentication, which underpins secured payments, Plug and Charge, and commercial V2G participation in energy balancing markets. Without a working certificate lifecycle, V2G transactions cannot be trusted or billed.

5. Which connector variants can MIDA supply for different markets? MIDA’s cable and connector range covers CCS1 (80–500 A), CCS2 (125–1,000 A), CHAdeMO (125–300 A), GB/T (200–1,000 A) and NACS (250–600 A). Selection should match the target market’s vehicle fleet, not a global default.

6. How does ISO 15118-20 Amendment 1 affect existing OEM/ODM programmes? It expands scope rather than replacing the base standard. Most existing ISO 15118-20 implementations remain valid, but programmes targeting megawatt-scale charging or bidirectional AC DER services should verify that the new procedures and security enhancements are included in the firmware roadmap.

7. Is multiparty interoperability available for V2G today? Not reliably. The IEA reports that all current commercial V2G offerings combine specific EV models with specific chargers and a specific utility, and that test procedures for multiparty interoperability are still under development. Buyers should favour solutions designed for interoperable operation when they become available.

Protocol status, revenue ranges and payback figures reflect IEA and CharIN publications as cited in the article text. All economic figures are illustrative scenario assumptions and should not be presented as guaranteed MIDA results.