Victron GX Integration

Charger Connection To GX

Phaeton has two separate connections to the GX: the charger connection, through which the GX shows and can control the charger, and the solar and battery readings described below.

Phaeton appears on the GX as a Victron EV Charging Station, connected over MQTT or Modbus TCP. New GX installations use MQTT, which the GX needs to take over Auto charging. On an older GX installation, the connection is under Settings → Victron GX → Charger connection to GX. Choosing the Auto mode Controlled by the Victron GX switches this connection to MQTT; the broker address and identity you entered are kept.

On another computer, current Venus OS versions accept a charger's MQTT messages only from a paired device. To pair, choose the Auto mode Controlled by the Victron GX under Settings → Charging (if it is already chosen, choose MQTT discovery under Charger connection to GX), enter the GX address as the GX broker address under Settings → Victron GX, apply the changes and choose Pair with GX. Then activate Pairing mode on the GX under Settings → Integrations → MQTT Devices, or press the GX button twice. Pairing needs Venus OS 3.80 or later. MQTT Access under Settings → Integrations on the GX can stay as it is: if it is Off, the first pairing switches it to Paired devices only, which opens only the encrypted port.

Without pairing, choose Legacy Modbus under Charger connection to GX, add Phaeton on the GX under Settings → Integrations → Modbus Devices → Saved devices, with Phaeton's address, its EVCS Modbus port and unit 1, and choose the Auto mode Battery-powered or Feed-in.

On the GX itself, the EVCS Modbus port is 1502, because the GX's own Modbus TCP server uses port 502; Settings refuses 502 there. On another computer it is 502 unless you change it.

Settings Fixed On The GX

When Phaeton runs on the GX, Settings shows some values as fixed, with the reason, instead of as a choice:

• Read solar & battery data is always on, and the readings come from this GX.
• The charger connection offers no No GX connection, because Phaeton on the GX always connects to it.
• On a new installation on the GX, and on a charger added under Chargers on this GX, the connection is MQTT discovery, with the reason "Phaeton installed on this GX always connects to it over MQTT."
• On those installations the MQTT client ID, the charger device ID, the web port, the state and log file paths and the EVCS Modbus server settings are fixed too; the EVCS Modbus server stays off.

GX Data For Auto Mode

Auto mode reads solar, grid, house use and battery values from the GX. On the GX itself, Phaeton always reads them. On another computer, turn on the setting Read solar & battery data under Settings → Victron GX → Solar & battery readings; in setup, it is called Read solar and battery data from GX. Inverter protection (Settings → Charger & installation) also uses these readings, in every charge mode.

When Phaeton connects to the GX over MQTT, it reads these values over that connection, as a Victron EV Charging Station paired over MQTT does. The GX's Modbus TCP server is then not needed.

Otherwise Phaeton reads them over Modbus TCP from unit ID 100. Turn on Settings → Integrations → Modbus TCP Server on the GX (on older GX menus: Settings → Services → Modbus-TCP). On another computer, also enter the GX address under Solar & battery readings; the GX Modbus port is usually 502.

How Phaeton Reads The GX

Phaeton reads the GX the way a Victron EV Charging Station does.

• Over Modbus TCP, it reads solar, grid, house use, the active AC input and the home battery once a second over one connection. It looks for the inverter on the unit IDs a charging station tries, one per second, and reads the inverter's state, input current limit, and overload and temperature alarms from the VE.Bus inverter or Multi RS that answers.
• Over MQTT, it reads the same values from the GX. The GX address, Modbus port and unit ID settings then do not apply. The inverter state shown is the GX system state, and a Multi RS reports no overload warning, as with a charging station.
• As on a charging station, the input current limit read from the inverter is not used: the AC input check of inverter protection uses the Input current limit setting. Phaeton does not read the ESS minimum state of charge.
• Phaeton keeps the GX address you entered. Unlike a charging station, it does not search the network for the GX when the connection fails.

When GX Data Is Missing

Over Modbus TCP, a failed read closes the connection and Phaeton reconnects five seconds later. A lost MQTT connection is retried after one second.

• Auto keeps working with GX data up to two minutes old: it can start and its timers keep running, but it raises or lowers the current only while the data is at most five seconds old.
• After two minutes without GX data, Auto stops charging. The Charging page shows Waiting for GX data, and the GX shows Waiting for sun. When the data returns, charging starts again after the start delay.
• Manual charging, and Auto while the Victron GX controls charging, do not depend on the GX data. Without it, though, inverter protection cannot detect an overload or a hot inverter.
• Scheduled charging needs the data only for a price-based window with a home battery minimum.

Validation

• Over Modbus TCP, use the Test GX data connection button in the setup wizard.
• Check that the dashboard shows plausible solar, grid and battery values before you rely on Auto mode.
• Confirm that the EV Charging Station appears in the GX device list.
• If the readings look right but Auto behaves unexpectedly, compare the dashboard values with the GX device list before you change thresholds.

Charging modesPhases and inverter protection