Simulating a charger

This guide walks through a complete OCPP 1.6 session, from boot to a stopped transaction, and shows where to inject the edge cases worth testing.

Session walkthrough

1. 1

   Boot

   On connect the charger sends BootNotification. Until it receives Accepted, a compliant charger should only send BootNotification and Heartbeat.

2. 2

   Connector status

   StatusNotification drives the connector through its lifecycle. Test that your CPMS reflects each transition and handles Faulted / Unavailable out-of-band.

   Available → Preparing → Charging → Finishing → Available

3. 3

   Authorize and start

   If the CPMS returns Accepted on authorize, follow with StartTransaction carrying the connectorId, idTag, meterStart, and timestamp.

   authorize.json

   [2, "msg-020", "Authorize", { "idTag": "TAG-123" }]

4. 4

   Meter values

   During the session, emit MeterValues on the configured interval. Vary the sampled values to exercise billing and live-session UI.

5. 5

   Stop

   StopTransaction closes the session with meterStop, a reason, and an optional transaction data array. Confirm the CPMS computes the correct energy delivered.

Sample messages

1[
2  2,
3  "msg-021",
4  "StartTransaction",
5  {
6    "connectorId": 1,
7    "idTag": "TAG-123",
8    "meterStart": 0,
9    "timestamp": "2026-01-15T12:00:00Z"
10  }
11]

Edge cases to inject

• Disconnect between StartTransaction and StopTransaction
• MeterValues with a decreasing register (clock/meter rollback)
• StopTransaction with reason: "PowerLoss"

The left sidebar lists Overview, Actions, and Test cases only (not every message). Open the index pages below or use ⌘K search — hit labels include the protocol version (for example · OCPP 1.6) so same-named actions stay distinct.

Related

• Connect a charger
• Connecting to your CPMS
• OCPP 1.6 actions