What happens when the Gateway Connect loses the internet connection? (Fail-Safe)

Summary

This article explains what happens when the GATEWAY loses its internet connection while maintaining a local area network (LAN) connection to the charging stations. It covers the impact on charging sessions, power distribution, and rebilling via the Charge Point Operator (CPO) backend.

Scenario

• Internet Connection: Lost
• Local Network (LAN): Functional between GATEWAY and charging stations
• Protocol: OCPP communication between chargers, GATEWAY and CPO backend

Behaviour in Case of Internet Loss

1️⃣ New Charging Sessions

• Without an internet connection, the GATEWAY cannot communicate with the CPO backend.
• Impact:
  • No new charging sessions can be authorised by the CPO backend.
  • Depending on the charger configuration, one of the following fallback modes applies:

    • Failsafe: Free-vend Mode

      Some chargers can be configured to dispense electricity without authorisation when disconnected from the backend.

    • Whitelist Mode

      If the charger supports a locally stored whitelist of authorised RFID tags, it may allow specific users to start charging sessions without backend approval.

2️⃣ Ongoing Charging Sessions

• Charging sessions already in progress at the time of disconnection continue based on the latest Smart Charging Profile received before the internet loss.
• The GATEWAY and chargers remain operational locally and will enforce the last known power limits until communication is restored.

3️⃣ Minimum Power Failsafe Setting in HARMON-E

• HARMON-E cannot perform authorisation independently of the backend.
• A TxDefaultProfile can be configured in HARMON-E to set a minimum fallback charging current (e.g. 6A per charger).
• This ensures that, even in the absence of an internet connection, chargers can provide a low-level charge instead of being completely disabled.

4️⃣ OCPP State Configuration (Advanced Option)

• The ocpp-state-config setting (not yet available in the HARMON-E UI) allows defining how chargers should behave in different OCPP connection states.
• Example use:
  • Specify what power allocation is applied when chargers lose connection to the backend.
  • Disable error handling for chargers going offline to avoid unnecessary load management restrictions.

5️⃣ Rebilling Considerations

• If charging sessions cannot be authorised, they are not recorded by the CPO backend, meaning no billing data is available for those sessions.
• Free-vend sessions will dispense electricity without creating a billable transaction in the backend.
• Sessions allowed via a local whitelist will forward transaction data to the backend once the connection is restored, allowing for delayed billing.

Recommendations for Customers

1. Configure Charger Fallback Policies:
   • Decide whether chargers should enter free-vend mode or whitelist mode when offline.
   • Ensure whitelist data is properly configured if using that option.
2. Set a TxDefaultProfile in HARMON-E:
   • Define a minimum fallback current (e.g. 6A) to avoid complete service loss during outages.
3. Plan for Safe Power Limits:
   • Determine what is a safe and acceptable fallback power level for your site.
4. Coordinate with FLEXECHARGE Support:
   • If needed, request configuration assistance or future ocpp-state-config support.

Key Takeaways

• Without an internet connection, no new sessions can be authorised via the CPO backend.
• Fallback behaviour depends on the charger configuration, not just the Gateway or HARMON-E.
• Ongoing sessions follow the last known profile.
• Proper fallback and whitelist settings are crucial to maintain service and allow delayed rebilling after connection recovery.