Phases and Inverter Protection

Phase Settings

The phase settings, under Settings → Charger & installation → Phases, follow the Victron EV Charging Station. Victron's manual does not describe switching between one and three phases.

• Multiple relay charging lets the charger switch between one and three phases. Off, the default for new installations, Phaeton leaves the phases as they are in every mode.
• Manual mode phase: Three phases or One phase, in Manual and Scheduled. The phase control on the Charging page sets the same setting. A change while charging stops charging, switches and starts again.
• Auto mode phase: Three phases, One phase, or One or three phases. A change while charging restarts the session.

On a new installation both phase settings are One phase, so check them when you turn Multiple relay charging on. Only allow switching when the installation and the charger support it; see the Charger Settings Checklist.

Switching In Auto

With Auto mode phase set to One or three phases, every Auto session starts on one phase. Auto switches to three phases when the charger's own power stays above Three phases above (4,800 W), and back to one phase below One phase below (4,300 W).

• The power must stay past a threshold for longer than Switch after (10 seconds). A dip between the two thresholds does not restart that time.
• Auto switches no sooner than Time between switches (60 seconds) after a session starts or after the last switch.
• These settings are under Advanced in Phases.

On one phase the charger delivers about 230 W per ampere: 3,700 W at a 16 A charging limit. With the default Three phases above (4,800 W), Auto therefore stays on one phase unless one phase can deliver more, as with a 32 A charging limit.

How A Phase Switch Works

Every switch stops charging, waits until the charger confirms that no current flows, keeps charging stopped for Stopped before switching (10 seconds), changes the phases and checks them, and then charging restarts; in Auto at the minimum current. The Charging page and the Victron GX show Switching to 3 phases or Switching to 1 phase meanwhile.

If the charger does not confirm the stop within three minutes, or does not confirm the new phases, charging continues on the present phases and Phaeton tries again after Time between switches.

Relays off delay is kept for the Victron GX. Phaeton waits for the charger to confirm zero current instead.

Phase Switching Check

Multiple relay charging allows switching; it does not prove that the charger can switch. Phaeton checks that by itself: once Multiple relay charging is on and the charger has been idle for Stopped before switching, Phaeton changes the phases and changes them back, without charging. Settings then shows that the charger switches.

• Without an idle moment, the check waits until the session ends.
• Some chargers are checked only while no car is plugged in.
• A check that does not pass runs again five minutes later.
• For some chargers Phaeton remembers the result, so it does not check again after a restart.

Phases Under GX Control

When the Victron GX controls Auto, it chooses the phases itself, at once, but only with Multiple relay charging on and Auto mode phase set to One or three phases.

With a fixed Auto mode phase, the charger uses that phase count under GX control too, once Phaeton has seen it switch. Until then, and without Multiple relay charging, it stays on its phases. The GX is offered both phase counts once Phaeton has seen the charger switch, in its check or in a phase change.

When Phase Settings Do Not Apply

The phase settings do not apply while Single-phase only is on, when the charger integration cannot switch phases, after the charger refused a phase change, or after three phase changes in a row did not complete. Settings says which applies.

• After a refusal or failed changes, fix the charger's phase switching setting. Phaeton's next check sees the charger switch and resumes on its own.
• When the changes failed because the charger did not confirm that charging stopped, Settings says so and Phaeton does not check again by itself. Check the charger and the car.
• Then, or to try again at once, choose the phases on the Charging page, or change Multiple relay charging, the Manual mode phase or the Auto mode phase.

Single-Phase Only

For an installation that must never charge on three phases, turn on Single-phase only under Settings → Charger & installation → Charging limits, or in the setup wizard. It applies at once in Manual, Auto, Scheduled and while the GX controls Auto, and it takes precedence over the phase settings and automatic switching. It stays off unless you turn it on.

• Phaeton allows no current until fresh charger readings confirm one phase.
• If the charger reports three phases, Phaeton first stops charging, waits for readings that confirm the stop, keeps charging stopped for Stopped before switching, and then requests and checks one phase.
• Phaeton never asks for three phases while the setting is on. A charger that already reports one phase is not switched.
• Saving the setting does not prove that the charger runs on one phase: check the status on the Charging page and that the charger reports 1 phase.

At the default 6 A minimum, single-phase charging starts from about 1,380 W instead of 4,140 W on three phases. Auto's other start conditions still apply; this setting does not lower the minimum current or bypass battery, grid or installation limits.

If readings are missing or stale, or the charger reports three phases, charging stays blocked, and the Charging page shows the step it waits for. Check the charger's installation settings and phase controls. After a refusal or mismatch, apply the settings again, reconnect the charger, or choose Retry single-phase verification on the Charging page. Connection failures are retried a limited number of times, each after Time between switches. Fresh one-phase readings clear the block without another phase change.

With an integration that cannot switch phases, Settings does not accept Single-phase only or Multiple relay charging. Turning Single-phase only off removes the restriction without asking for three phases at once; the phase settings apply again.

Inverter Protection

Like a Victron EV Charging Station, Phaeton protects your Victron inverter in every charge mode. Both protections use the solar and battery readings from the GX (see GX data for Auto mode) and are set under Settings → Charger & installation → Inverter protection, together with the wiring position. The GX can read and change them too.

Charger wired on tells Phaeton where the charger is connected, and decides how overload protection finds an overload:

• AC output (ESS/load side): between the inverter and your loads. Charging follows the inverter's own overload warnings.
• AC input (grid side): on the grid side of the inverter. Phaeton keeps the grid current of each phase the car charges on below the Input current limit (15 A by default). Set it to the inverter's AC input current limit. This check applies only while the GX reports a grid or generator input.

Victron's manual describes this limit as read from the inverter, but the charging station's firmware, like Phaeton, uses the setting.

Overload Protection

Overload protection is off by default, as on a charging station. When it is on and an overload occurs, the charger drops to the minimum current at once.

• If the overload lasts longer than Pause after (5 seconds), charging pauses. An overload alarm from the inverter pauses it at once.
• Charging starts again by itself once the overload has stayed away for Restart after (10 seconds). On the AC input it also waits until every phase has room for the minimum current.
• After an overload, the current is lowered by Lower the current by (20%, at least 1 A, not below the minimum) for Lowered current lasts (5 minutes) after the last overload. Lower the current after overloads sets how many overloads in a row lower it.
• Changing the charge mode while charging, unplugging the car or Stop ends the lowered current.

Victron's manual describes a 10% reduction after several overloads; the defaults here, 20% after every overload, are those of the charging station's firmware.

While overload protection pauses charging, the Charging page shows Paused: inverter overload or Paused: inverter input limit, and the GX shows the charger as Connected. A start command during that time is refused. Over MQTT the GX also shows the warning Overload active while the protection holds charging, and Overload detected afterwards, until a car is connected again; see Codes on the GX.

Inverter Temperature Protection

Inverter temperature protection is on by default. While the inverter reports a high temperature warning or alarm, charging continues at the minimum current. It returns to its normal current High temperature hold (60 seconds) after the last report, and it never stops charging.

As on a charging station, the Feed-in Auto mode ignores it and follows the grid export. Over MQTT the GX shows the warning The charging current is limited due to inverter overtemperature.

Without GX Readings

Without readings from the GX, before the first readings and when the readings are more than two minutes old, neither protection acts. When no inverter answers, only the AC input check can act. Over MQTT a Multi RS reports no overload warning to a charging station, so on its AC output overload protection cannot act.

Charger Settings ChecklistCharging modesVictron GX setup