kevinferron.comKevin Ferron

The V2X standards map

Which standard governs which link between the grid and the car, for AC and for DC, and where each one stands: published, draft or still under consideration.

  • ISO 15118-20
  • OCPP 2.1
  • IEC 61851
  • IEEE 1547
  • UL 1741
  • CHAdeMO
Charging
Region

Showing every standard. International standards match every region, and one that is not tied to AC or DC matches both.

  1. Grid ↔ aggregator

    The utility or market telling an aggregator or site what the grid needs.

    AC

    Either, or not specific

  2. Back office ↔ charger

    The charging network’s software sending schedules and limits to a charger.

    Either, or not specific

  3. Charger ↔ car

    The cable: how the charger and the car agree what to do.

    Either, or not specific

    DC

  4. Charger or car hardware

    What the charging equipment itself has to be and do.

    AC

    Either, or not specific

    DC

  5. Interconnection

    The rules and certification for something that can feed power into the grid.

    AC

    Either, or not specific

Published Draft Under consideration Not stated

ISO 15118-20: Second-generation communication between the car and the charger

ISO 15118-20: Second-generation communication between the car and the charger

Published

ISO’s catalogue abstract and its openly published XML schemas. The 561-page text was not read.

Published by
ISO/TC 22/SC 31
Edition
Edition 1, 2022-04, 561 pages. Amendment 1 published 2026-07.
Link it governs
Charger ↔ carIt is the message set between the car’s and the charger’s controllers.ISO 15118-20: Abstract
AC or DC
Either, or not specificISO’s schemas define an AC message set and a DC message set, each with bidirectional variants.ISO 15118-20 DC messages (XSD): Charge parameter discovery and charge loop, with discharge variants
Region
InternationalAn international standard.
Status
PublishedAmendment 1 is titled for an AC DER service, an MCS service and an improved security concept. Its catalogue page has no abstract, so whether it changes bidirectional transfer is not stated.ISO 15118-20 Amd 1: Title and general information

What it governs for V2X

  • Communication between the car and the charger over IP. Its messages support power transfer in both directions, and it defines the messages and sequence requirements for bidirectional power transfer.ISO 15118-20: Abstract
  • No message pair is bidirectional-only. Discharge appears as variants inside the shared charge-parameter and charge-loop messages, as one optional field in the power-delivery request and as optional bidirectional fields in the meter record, a discharged-energy counter and an inductive reactive-energy reading.ISO 15118-20 common types (XSD): Meter info type; the variants and the direction field are in the DC, AC and common-messages files
  • The AC set has charge-parameter and charge-loop messages only; it has no cable-check, pre-charge or welding messages.ISO 15118-20 AC messages (XSD): AC message pairs

From the spec

  • Direction is a flag with two values, charge and discharge, in an optional field of the power-delivery request. Limits take their direction from separate field names for charge and discharge, not from a sign.BPT_ChannelSelectionchannelSelectionTypeISO 15118-20 common messages (XSD): PowerDeliveryReq and its channel selection type
  • The schedule exchange can carry a discharging schedule beside the charging one, and the dynamic-mode requests can carry V2X energy requests. The schemas do not state the units of any of these values.DischargingScheduleEVMaximumV2XEnergyRequestISO 15118-20 common messages (XSD): Schedule tuple type; dynamic schedule-exchange request; the schema carries no annotations

Bidirectional charging is not one standard. Between the grid and the battery there is a chain: a utility or market, an aggregator, the charging network’s back office, the charger and the car, and a different document governs each link. In OCPP’s own picture the utility does not talk to stations or cars directly. The charging operator acts as the aggregator and passes the utility’s controls down, and the IEA says aggregators mostly run those back offices as a packaged service. The map above puts each standard on the link it governs, and says whether it is for AC, for DC or for neither in particular.

At the cable, ISO 15118-2 is charge-only: its messages support energy transfer from the charger to the car, and the bidirectional use cases wait in Part 1. ISO 15118-20 added them, but as variants inside shared messages rather than a separate set, and its schemas state no units, no message order and no service numbers. Those come from open-source implementations such as Josev. The IEA adds that -20 is not yet implemented consistently: today’s V2G offers are typically one car model paired with one charger model over proprietary protocols, and conformance tests are still being developed.

The split that shapes everything else is where the inverter sits. In DC bidirectional charging it is in the charger, which becomes the distributed resource a utility cares about. In AC it is in the car. California’s Rule 21 process already covers DC V2G, while AC V2G was limited to a pilot until the standards for it were in place: SAE J3072, UL 1741 SC and a profile joining J3072 to IEEE 2030.5. That is the CPUC’s position in April 2025. The SAE standards here rest on secondary sources, because SAE’s catalogue could not be opened: what the map says about J3072, J2847/3 and J2836/3 comes from the CPUC, a 2012 DOE report and OCPP 2.1.

AC, one inverter in the car

Converter in the car; smart functions in the car.

AC, split inverter

Converter in the car; smart functions in the charger.

DC, inverter in the charger

Converter in the charger; smart functions in the charger.

Power converter Smart-inverter functions

IllustrationWhere the power converter and the smart-inverter functions sit in three bidirectional set-ups. Left box in each sketch: the charger. Right box: the car. A sketch of the idea, not a wiring diagram.

Above the charger, OCPP 2.0.1 has no discharge. OCPP 2.1 adds a block for bidirectional transfer, in which each schedule period carries a signed setpoint, a charge limit and a discharge limit and the charger rejects a profile that falls outside them, and a block for DER control that carries a utility’s grid-code settings down to the charger and, through Amendment 1 of ISO 15118-20, on to the car. OCPP does not prescribe the protocol on the utility side. It names IEC 61850 (mostly Europe and Asia) and IEEE 2030.5 (mostly the USA), and OpenADR sits at the programme layer, sending prices and events that a fleet’s own systems turn into charging or discharge.

Several of these are not finished. IEC 61851-1 Edition 4, which would define the bidirectional requirements for AC Mode 3 stations, was a draft at the last reading, and IEC 61851-23 specifies bidirectional equipment for one of its three DC systems only. In Europe, AFIR defines bidirectional recharging and the EPBD recast says recharging points will have to enable it where appropriate, but the legal texts could not be read here, so the dates for ISO 15118-20 under the 2025 delegated act are CharIN’s reading, not the law. CHAdeMO says it has more than 10,000 bidirectional units installed, its own count with no date, and calls ChaoJi capable of V2X without giving plans.

Where the sources are silent the map says so rather than filling the gap: the edition of UL 9741 and of SAE J2847/3 and J2836/3, which CHAdeMO version first added discharge, whether ISO 15118-20’s amendment changes bidirectional transfer, and ChaoJi’s V2X plans. A standard’s status here is the status of the document, and its panel lists any part of it still open.

Sources

  1. OCPP 2.1 Part 2 OCPP 2.1 Part 2: Specification, 803 pages. Edition 2, 2025-12-03; CC BY-ND 4.0 (in the free download set).

    • Part R, chapter 1, p. 540
    • Part R, sections 2.2 to 2.3, pp. 541-542
    • Part R, section 2.2, pp. 541-542
    • Part R, sections 2.3 to 2.5, pp. 542-543
    • Part Q, sections 2.1 and 2.5; Part R, section 2.1
    • Part R, section 2.1, p. 541
    • Part Q, sections 2.1 and 2.5, pp. 500 and 506
    • Part R, chapter 1 and section 2.1, pp. 540-541
    • Part Q, section 2.2, pp. 500-501
    • Part R, sections 2.2 to 2.5, pp. 541-543
    • Part R, section 2.1, table 161, p. 541

  2. IEA: vehicle-to-grid technology IEA, “Vehicle-to-grid technology” (part of Global EV Outlook 2026). 2026-05-20, CC BY 4.0.

    • The charging station management system paragraph
    • The international communication standard paragraph

  3. ISO 15118-2 ISO 15118-2:2014, Part 2: Network and application protocol requirements. Ed. 1, 2014-04 (catalogue abstract).

    • Abstract, first paragraph
    • Abstract
    • General information
    • General information, life cycle

  4. ISO 15118-20 common messages (XSD) V2G_CI_CommonMessages.xsd, ISO’s openly published schema. Ed. 1, last modified 2021-10-12.

    The schema carries no annotations: no units, no message order and no service numbers.

    • Message pairs; the schema has no annotations
    • PowerDeliveryReq and its channel selection type
    • Schedule tuple type; dynamic schedule-exchange request; the schema carries no annotations

  5. Josev Open-source ISO 15118 implementation in Python (SwitchEV iso15118): the order of the messages in a session. Version 0.31.2, commit 1d29f53982d3, 2026-10-13.

    One implementation’s state machine, not ISO text.

    • State machine in iso15118_20_states.py

  6. CPUC VGI forum, 2025 CPUC Energy Division, “Vehicle-Grid Integration Forum: Interconnection”, 8 slides. 2025-04-16.

    A regulator’s slide deck; it calls its own dates approximate. It is also where the SAE J3072 facts on this page come from, since the SAE catalogue could not be opened.

    • Slides 2 to 5
    • Slide 5

  7. INL V2G regulations review, 2012 Vehicle-to-Grid (V2G) Power Flow Regulations and Building Codes Review by the AVTA (INL/EXT-12-26853, for DOE). September 2012.

    Old: it describes the SAE drafts of its time, not current editions. It is the only place the SAE J2847/3 and J2836/3 facts on this page come from.

    • Sections 4.6.3-4.6.4, pp. 54-55
    • Sections 4.6.3-4.6.4

  8. CPUC V2G AC subgroup report, 2019 Final Report of the Vehicle to Grid Alternating Current Interconnection Subgroup (R.17-07-007, filed by CESA). 2019-12-11, 118 pages.

    Older than ISO 15118-20 and IEEE 1547-2018 rule changes; read for the architecture. It is also where the SAE J3072 and J2836/3 facts on this page come from.

    • Pages 17 and 26
    • Page 2, Gap 1
    • Page 26
    • Executive summary and introduction
    • Pages 3-4, Gap 2

  9. OCPP 2.0.1 Part 2 OCPP 2.0.1 Part 2: Specification, 491 pages. Edition 4, 2025-12-03; CC BY-ND 4.0 (in the free download set).

    • Part K, chapter 1, p. 238 (text search)
    • Part K, chapters 1 and 2, pp. 238-240
    • Part K, use cases K15 to K17
    • Part K, section 2.4, p. 240

  10. OpenADR on DER and V2G OpenADR Alliance, “DER, V2G, and how it relates to OpenADR”. As fetched 2026-10-24; mentions a February 2026 white paper.

    The Alliance describing its own role.

    • DER, V2G and OpenADR

  11. IEC 61851-1 Ed. 4 CDV E DIN EN IEC 61851-1 (VDE 0122-1):2026-06, draft of IEC 69/1069/CDV:2025. Draft issued 2026-06, published 2026-05-15, comments due 2026-07-15 (VDE’s description, in German).

    A draft. What the vote decided is not stated.

    • Description
    • Description, change h

  12. IEC 61851-23 IEC 61851-23:2023, DC electric vehicle supply equipment. Ed. 2.0, 2023-12-13, 383 pages (catalogue abstract).

    • Abstract

  13. EC: AFIR Q&A European Commission, Questions and Answers on Regulation (EU) 2023/1804 (AFIR). As fetched 2026-10-24.

    The Commission’s Q&A. The regulation’s own text on EUR-Lex was not readable and was not read.

    • Question 2.2
    • Questions 2.3 and 2.26

  14. EC: EPBD European Commission DG ENER, Energy Performance of Buildings Directive page. As fetched 2026-10-24.

    The Commission’s summary. The directive’s own text on EUR-Lex was not readable and was not read.

    • Modernisation and digitalisation
    • Revised Energy Performance of Buildings Directive

  15. CharIN on AFIR CharIN position paper, “Clarifying ISO 15118 Implementation under AFIR — Commission Delegated Regulation (EU) 2025/656”. v1, 2026-04-28, 11 pages.

    An industry body’s reading of the regulation, not the legal text.

    • Sections 1 and 2.1
    • Section 3.5
    • Sections 3.1 and 4.2

  16. CHAdeMO V2G/VGI CHAdeMO Association, V2G / VGI page. As fetched 2026-10-24.

    The Association describing its own protocol; its counts carry no date.

    • Introduction
    • Introduction; VGI applications

  17. CHAdeMO ChaoJi CHAdeMO Association, High Power (ChaoJi) page with roadmap. As fetched 2026-10-24.

    The Association describing its own protocol.

    • ChaoJi key features
    • CHAdeMO 3.0 (ChaoJi); key features

  18. ISO 15118-20 Amd 1 ISO 15118-20:2022/Amd 1: AC DER service, MCS service, and improved security concept. Ed. 1, 2026-07 (catalogue title only; the page has no abstract).

    • Title and general information

  19. ISO 15118-20 ISO 15118-20:2022, Part 20: 2nd generation network layer and application layer requirements. Ed. 1, 2022-04 (catalogue abstract).

    • Abstract

  20. ISO 15118-20 DC messages (XSD) V2G_CI_DC.xsd, ISO’s openly published schema. Ed. 1, last modified 2021-08-23.

    The schema carries no annotations: no units, no message order and no service numbers.

    • Charge parameter discovery and charge loop, with discharge variants

  21. ISO 15118-20 common types (XSD) V2G_CI_CommonTypes.xsd, ISO’s openly published schema. Ed. 1, last modified 2021-10-12.

    The schema carries no annotations: no units, no message order and no service numbers.

    • Meter info type; the variants and the direction field are in the DC, AC and common-messages files

  22. ISO 15118-20 AC messages (XSD) V2G_CI_AC.xsd, ISO’s openly published schema. Ed. 1, last modified 2021-08-23.

    The schema carries no annotations: no units, no message order and no service numbers.

    • AC message pairs

  23. ISO 15118-2 schemas ISO’s openly published schema folder for ISO 15118-2 (five XSD files). Folder named ed-2; MsgBody last modified 2013-08-20.

    The catalogue lists the published -2 as Edition 1, 2014.

    • Energy transfer mode type
    • All five schema files; energy transfer mode type
    • Message body: power delivery and current demand

  24. ISO 15118-1 ISO 15118-1:2019, Part 1: General information and use-case definition. Ed. 2, 2019-04 (catalogue abstract).

    • Abstract; general information

  25. IEC 61851-1 IEC 61851-1:2017, general requirements for electric vehicle supply equipment. Ed. 3.0, 2017-02-07, corrigendum of Nov 2023 included (catalogue abstract).

    • Abstract

  26. IEC 61851-23 preview IEC 61851-23:2023, contents and scope pages hosted by VDE Verlag. Ed. 2.0.

    Contents and scope only (44 pages extracted).

    • Contents
    • Contents, Annex DD

  27. IEC 61851-24 IEC 61851-24:2023, digital communication between a DC charging station and the vehicle. Ed. 2.0, 2023-12-13 (catalogue abstract).

    • Abstract
    • Catalogue entry

  28. IEC 63110-1 IEC 63110-1:2022, the base part of a protocol for managing EV charging and discharging infrastructure. Ed. 1.0, 2022-07-29, 314 pages (catalogue abstract).

    • Abstract
    • Catalogue entry

  29. IEC 63110-1 preview IEC 63110-1:2022, contents, foreword and scope pages hosted by VDE Verlag. Ed. 1.0.

    Contents, foreword and scope only.

    • Contents, clauses 8.2.3 to 8.2.10
    • Normative references

  30. IEC 62909-2 IEC 62909-2:2019, bi-directional grid-connected power converters, Part 2: interface to EV, battery and PV resources. Ed. 1.0, 2019-03-08, 46 pages (catalogue abstract).

    • Abstract
    • Catalogue entry

  31. CHAdeMO, DC V2X, 2019 CHAdeMO Association, “DC V2X systems: advantages and evolution”, Lyon, 22 slides. 2019-05-20.

    The Association’s own view.

    • Slide 8
    • Slide 3

  32. IEC 62909-2 preview IEC 62909-2:2019, contents pages hosted by VDE Verlag. Ed. 1.0.

    Contents only.

    • Contents, clause 101
    • Contents, figures

  33. IEC TR 61850-90-8 IEC TR 61850-90-8:2016, how the IEC 61850 DER model can represent EVs and chargers. Technical report, Ed. 1.0, 2016-04-07, 79 pages (catalogue abstract).

    • Abstract

  34. IEC TR 61850-90-8 preview IEC TR 61850-90-8:2016, scope and normative references pages hosted by VDE Verlag. Ed. 1.0.

    Scope and normative references only.

    • Clause 1, scope

  35. CHAdeMO protocol CHAdeMO Association, protocol development page. As fetched 2026-10-24; version numbers read from the image file names.

    The Association describing its own protocol.

    • Protocol versions

  36. Battery-Emulator Open-source battery emulator, CHAdeMO “V2X mode” (CHADEMO-BATTERY.h and .cpp). Commit 7d03ad5d07a5, 2026-10-23.

    One project’s reading of the protocol, not the specification.

    • CHADEMO-BATTERY.h and .cpp, discharge frames

  37. SAC/SAMR announcement 2023 No. 9 National Standard Announcement 2023 No. 9, listing GB/T 18487.1-2023, GB/T 20234.4-2023 and GB/T 27930-2023. 2023-09-07, effective 2024-04-01.

    • Announcement list

  38. CHAdeMO on ChaoJi as GB/T CHAdeMO Association news (Japanese): ChaoJi published as a Chinese national standard. 2023-09-19.

    • News item

  39. OpenChaoJi EVerest open-chaoji: an open-source ChaoJi and GB/T 27930 stack. Commit 33aef28c820814cf37b6ef87855f7002a1e8c5c6, 2025-06-04.

    One project’s code, not the GB/T text, which was not read.

    • Configuration and message definitions

  40. OCA: OCPP Open Charge Alliance, Open Charge Point Protocol page. As fetched 2026-10-24.

    • Introduction

  41. OCA: OCPP 2.1 testing Open Charge Alliance news, “New milestone: OCPP 2.1 testing is now available!”. 2026-10-12.

    • News item

  42. OCA: OCPP 2.1 released Open Charge Alliance news, “OCPP 2.1 is now available!”. 2025-01-23.

    • Release news

  43. OCPP 2.1 Part 0 OCPP 2.1 Part 0: Introduction. Edition 2, 2025-12-03; CC BY-ND 4.0 (in the free download set).

    • Section 1.1, p. 3
    • Chapter 2, p. 6

  44. OCA home page Open Charge Alliance, home page (“About us”). As fetched 2026-10-24.

    • About us

  45. CSIP 2.1 Common Smart Inverter Profile: IEEE 2030.5 Implementation Guide for Smart Inverters (CSIP Working Group). Version 2.1, March 2018.

    • Section 2, principles 7-8; section 3.1
    • Section 1
    • Section 1, p. 1
    • Text search of the whole guide
    • Section 1; section 2, principles 7-8
    • Sections 4.4.1 and 5.2.4
    • Table 1

  46. IEEE 2030.5-2023 IEEE 2030.5-2023 (catalogue page). Approved 2023-12-06, published 2024-12-11, active.

    • Abstract

  47. OpenADR overview OpenADR Alliance, Overview. As fetched 2026-10-24.

    • Overview

  48. OpenADR 3 OpenADR Alliance, OpenADR 3 Introduction and Certification Program. As fetched 2026-10-24.

    The OpenADR 3 specification itself sits behind an email form and was not read.

    • Sections 1 and 2

  49. OpenADR FAQ OpenADR Alliance, FAQ. As fetched 2026-10-24.

    • Questions 17 to 19

  50. IEEE 1547-2018 IEEE 1547-2018, Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces (catalogue page). Approved 2018-02-15, published 2018-04-06, active; amendment 1547a-2020; revision project P1547 open.

    • Abstract
    • Catalogue page

  51. IEEE 1547.1-2020 IEEE 1547.1-2020, the test procedures that confirm equipment conforms to IEEE 1547 (catalogue page). Approved 2020-03-05, published 2020-05-21, active; amendment P1547.1a proposed.

    • Catalogue page
    • Abstract

  52. UL 1741 UL Standards & Engagement catalogue entry for UL 1741. Edition 3, published 2021-09-28, last revised 2026-08-14.

    Scope text only; the catalogue page does not show the text of the supplements.

    • Scope, sections 1.1-1.2

  53. ChargedEVs on UL 1741 SC ChargedEVs, “UL releases an important new V2G standard”. 2026-07-31.

    Trade press, not UL.

    • Paragraphs 3 to 7

  54. CEC on UL 1741 SB California Energy Commission, “Changes to the Inverter and ESS Lists: UL 1741 3rd Edition inclusive of Supplement SB” (training slides). March 2022.

    • Slide 6

  55. EC: alternative fuels infrastructure European Commission DG MOVE, Alternative fuels infrastructure page. As fetched 2026-10-24.

    • Alternative Fuels Infrastructure Regulation

  56. EC: EPBD and mobility European Commission DG ENER, “Sustainable mobility and buildings”. As fetched 2026-10-24.

    • Charging point counts

Everything here is paraphrased from the pinned sources, not quoted. The SAE entries rest on secondary sources, because SAE’s own catalogue could not be opened; an industry body’s reading is labelled as one. Anything illustrative is labelled as such. Where a source is silent the page says so instead of filling the gap.