Where do evcharger Session/Cost / Session/SavedCost and the "Guest EV" vehicle name come from?

Q&A and troubleshooting
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Hello,

Follow-up to my setup: Cerbo GX (VenusOS v3.73), ESS 3 Phase Quattro-II 48/5000/70-2x50 + 2 x SmartSolar MPPT RS 450/200 + PV + ~30 kWh Pylontech battery. I integrated my openWB Series2 wallbox as an EV charger via the freakent dbus-mqtt-devices driver (v0.9.0), fed by a Node-RED flow that publishes the openWB MQTT values to the proxy. Power, current (L1), status, charged energy and session time all arrive correctly and are shown in VRM / Remote Console.

I have two related questions about EV charger / EV data paths that I cannot find documentation for.

1) evcharger Session/Cost and Session/SavedCost

Referring to the DBus wiki ( dbus · victronenergy/venus Wiki · GitHub ), the evcharger service defines:

  • /Session/Time — works, shown as “Charging time”
  • /Session/Energy — works, shown as “Charged energy”
  • /Session/Cost and /Session/SavedCost — these I cannot find anywhere in the UI.

I am publishing all four values, and I can confirm via dbus-spy that Session/Cost and Session/SavedCost do arrive correctly on the DBus. But while Time and Energy are displayed in VRM / Remote Console, Cost and SavedCost are not shown anywhere that I can find.

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Where are Session/Cost and Session/SavedCost intended to be displayed? Are they shown only on the display of a genuine Victron wallbox, used somewhere in VRM, or reserved for future use?

2) The com.victronenergy.ev service and the “Guest EV” name

When my car is charging, VRM/Remote Console labels the connected vehicle as “Guest EV” (a generic default name).

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My main question: where does this “Guest EV” name come from, and how can it be set/influenced?

I have already ruled out the obvious candidate: the evcharger’s CustomName is set to “My openWB” (that is the charger device name, and it works) — so “Guest EV” is clearly something vehicle-related, not the charger name. My assumption is that this comes from the separate com.victronenergy.ev service ( dbus · victronenergy/venus Wiki · GitHub ), i.e. that the vehicle name/identity is driven by that service and, since I don’t publish one, Victron falls back to “Guest EV”. But I could not confirm this anywhere.

The wiki documents com.victronenergy.ev with paths like /Soc, /TargetSoc, /VIN, /BatteryCapacity, /Odometer, /RangeToGo, /Position/*, /ChargingState and several LastUpdated/* timestamps (one even named for “E-node / Node-RED” as the provider). This is exactly the data I already have from my car (a Renault, read via its API) and would gladly publish.

My questions:

  • Where does the “Guest EV” name originate, and which path/service sets the displayed vehicle name? Is it com.victronenergy.ev (e.g. via /VIN, CustomName, or another path)?
  • Is the com.victronenergy.ev service already functional/rendered in VenusOS v3.73, and where does a registered EV appear (VRM, Remote Console, a vehicle tile, or only on a genuine Victron EVCS display)?
  • Would publishing this service replace the “Guest EV” label with the real vehicle name?
  • Is there any reference implementation or example for populating com.victronenergy.ev?

I could not find documentation or examples beyond the wiki page, which also carries a disclaimer that the paths may still change — so I assume this is fairly new.

Thanks in advance for any pointers.

2

I have wondered similar things and could not find anything as well.

My gues’t (pun intended) is that this is future functionality that is already present in the app, but has not been fully implemented on venus OS and the respective firmware of the EVSE yet.

So I guess we will see documentation once the functionality can be used, which requires releases of all the code involved…