Charging Station Behavior on Connection Loss
The content of this article is not required to know for normal operation of Edge. The topics are for when you want to understand and utilize Edge to its full potential.
Connection with EVC-net Lost
Edge acts as a stand-alone local backoffice. When your installation site loses internet connection, your chargepoints will remain working. Edge will sync all transactions to EVC-net when the connection returns.
Card Authorizations
By default Edge uses its own transaction database to authorize cards previously used at that location. If Edge cannot locally authorize a card when offline, it will accept the unknown card and sync the transaction with EVC-net later. This maintains site operation since invalid cards are rarely used during network outages. Card database behavior can be modified in Settings → Charge cards → Card database options.
Allow offline TX for unknown card: Permits all cards for charging when there is no connection to EVC-net and the card cannot be authorized locally. This option is enabled by default.
Mode options:
| Mode | Description |
|---|---|
| CardDB(1) → EVC-net(2) (DEFAULT) | Checks local database first, then EVC-net. Fastest option but blocked cards remain valid in cache up to 2 weeks. |
| EVC-net(1) → CardDB(2) | Forwards authorizations to EVC-net first; uses internal database only if EVC-net is offline. |
| CardDB AND EVC-net | Authorizes through local database and also checks EVC-net. If EVC-net authorization fails, Edge stops the transaction after seconds. |
Connection with Stations Lost
While Edge is hardwired with Ethernet, chargepoints may theoretically go offline. Edge must ensure grid limits are not exceeded when stations or the controller are offline.
No Connection When Starting a Charging Session
By default, when a station connects to Edge it receives a default charging profile with 0A power usage. Only when the chargepoint starts a transaction does Edge overwrite this profile. This mechanism ensures chargepoints only consume power when they have a connection to Edge and the loadbalancer has determined that it is safe to charge.
Connection Loss During a Charging Session
Edge can send charging profiles that change current to a safe value after 60 seconds of receipt. Edge continues sending profiles so the station enters safe mode only if profile reception stops. Four configurable options exist in Settings → Advanced → Charging profile timeouts:
Timeout not enabled (default): Best for chargepoint compatibility. Loadbalancer reserves the station's last known current.
6A charging and clear reserved after timeout: Within 1 minute after connection loss, stations slow to 6A. Loadbalancer reserves 6A for the offline station.
Stop charging and clear reserved after timeout: Within 1 minute after connection loss, stations charge at 0A. Loadbalancer knows the station should not charge and will not clear reserved current.
Stop charging after timeout: Within 1 minute after connection loss, stations charge at 0A. Edge does not clear reserved current while the station remains offline, as it does not trust the chargepoint's correct handling of the charging profile.
Even without charging profile timeouts, Edge handles offline chargers by reserving their current and correcting newly started transactions with energy meters installed. However, Edge cannot respond to congestion when offline stations plus building load exceeds grid limits.
Charging profile timeouts use OCPP charging profiles with two timestamps. Some chargepoints may interpret these differently. Test thoroughly with your station model first by enabling settings and unplugging the network connector.
Updated 14 days ago