CharIN Publishes Updated CCS2 Standard with Bidirectional V2G Support

CharIN, the industry consortium that maintains the Combined Charging System (CCS) standard, has published an updated CCS2 specification that formally incorporates bidirectional power flow for vehicle-to-grid (V2G) and vehicle-to-home (V2H) applications. The update defines communication protocols built on ISO 15118-20, safety interlock requirements for grid-connected bidirectional sessions, metering accuracy standards, and the session management handshakes that allow an EVSE to negotiate energy export with a vehicle's battery management system. CCS2 already supported AC bidirectional charging under earlier ISO 15118 implementations; this update extends the standard to DC bidirectional sessions at higher power levels.

The significance is standardization across a fragmented landscape. Bidirectional charging is currently available on a handful of vehicles through separate implementations: the Nissan Leaf supports V2G via CHAdeMO with compatible EVSE, the Ford F-150 Lightning supports V2H through its Pro Power Onboard system using a proprietary transfer switch, and the Hyundai Ioniq 5 and 6 support V2G in markets where CCS2 bidirectional EVSE has received certification. Each of these uses different protocols and hardware, limiting the development of a unified bidirectional EVSE market. A formal CCS2 V2G specification creates a path for standardized hardware that works across the broad CCS2 vehicle fleet.

For homeowners interested in V2H capability — using an EV to power the home during outages or peak pricing windows — the practical timeline is 2–3 years from the specification publication to widespread certified EVSE availability. Certified bidirectional EVSE requires UL listing updates, utility interconnection approvals in most US jurisdictions, and OEM certification of each vehicle model's bidirectional implementation against the updated standard. Vehicles already equipped with ISO 15118-20 hardware, including several 2025–2026 model year EVs, are the most likely candidates for OTA firmware updates that unlock bidirectional capability as compliant EVSE becomes available.