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Use cases

These scenarios describe the 05/2023 VDV 261 protocol intent. The current repository implements payload validation and integration aids; it does not run the complete operational flow.

  • Discover VAS 3 and establish an HTTPS tunnel during an ISO 15118 charging session.
  • Send a complete flat vehicle state at seq = 0 and receive every backend field, using SNA values where needed.
  • Exchange changed values at the normal ten-second cadence while including h2_stat and bat_stat on every request.
  • Coordinate preconditioning from departure time, charging requirements and depot power constraints.
  • Report the time and estimated energy needed for preconditioning through prec_reqtime and prec_eamount.
  • Recover from timeouts through the defined retry and reconnect behaviour.
  • Use BetterFleet schema and diagnostic extensions during integration.

Summary flow

sequenceDiagram
    participant EV as EVCC
    participant SECC as SECC
    participant BF as BetterFleet backend

    EV->>SECC: Discover and request VAS 3
    EV->>BF: HTTPS POST flat JSON (seq 0, full available state)
    BF-->>EV: 200 flat JSON (all backend fields)
    loop Active charging session
        EV->>BF: Changed values plus h2_stat and bat_stat
        BF-->>EV: Changed departure and preconditioning directives
    end

See communication sequences for payload examples and retry behaviour.