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AC Power Distribution, Transfer Panels & Inverters

This document details the vessel's 230V Alternating Current (AC) distribution architecture, the Scheiber physical switch panels, the MasterVolt 2000W and Victron 375W inverters, and how their real-time states are decoded and published to Venus OS (Cerbo GX) and Node-RED.

1. System Architecture Overview

The vessel has two independent AC distribution panels / branch circuits:

  1. House AC Distribution Panel: Powers general 230V domestic outlets, galley equipment, battery chargers, and onboard conveniences.
  2. Air Conditioning (A/C) AC Distribution Panel: Dedicated high-power circuit for the vessel's climate control systems.

Inverters

  • MasterVolt 2000W Inverter: High-power inverter dedicated to supplying the House AC distribution bus when off-grid and without the generator. It does not power the Air Conditioning panel.
  • Victron Phoenix 375W Inverter: Standalone inverter dedicated to continuous Starlink power, connected directly via VE.Direct into Venus OS.
               ┌── [ Shore Power         ] ──┐
               ├── [ Onboard Generator   ] ──┤
               │                            ▼
               │                ┌──────────────────────┐
               ├───────────────►│  A/C Switch Panel    │──► Air Conditioning (230V)
               │                │ (Off/Shore/Generator)│    [CAN: 0x02400B90 & 0x02040B90]
               │                └──────────────────────┘
               │
               │                ┌──────────────────────┐
               ├───────────────►│  House Switch Panel  │──► House Sockets / Appliances (230V)
               │                │ (Off/Shore/Gen/Inv)  │    [CAN: 0x02400B88 & 0x02040B88]
               │                └──────────────────────┘
               │                            ▲
[MasterVolt 2000W Inverter] ────────────────┘ (Normally enabled fallback;
                                                supplies House only when selected)

[Victron 375W Inverter] ──────────────────────────────────► Starlink (Independent / VE.Direct)

2. CAN Bus Message Mapping & State Decoding

2.1 Applied Source Selectors (Receive-Only)

The physical Scheiber panel outputs applied feedback when source contactors change:

Channel CAN Frame ID Byte Offset Enum Values Description
House Panel Applied Source 0x02400B88 Byte 0 0x01 = OFF
0x02 = SHORE
0x04 = GENERATOR
0x08 = INVERTER (Effective)		 Current AC source contactor applied to House distribution bus
A/C Panel Applied Source 0x02400B90 Byte 0 0x01 = OFF
0x02 = SHORE
0x04 = GENERATOR		 Current AC source contactor applied to Air Conditioning bus

2.2 Inverter Configuration & AC Transition Markers

The MasterVolt is normally left enabled as the House fallback, but it has a physical OFF switch. House applied-source feedback determines whether it is actually supplying the bus. The shared transition frame is context-gated:

CAN Frame ID Byte Offset Value Event & Meaning
0x02140898 Byte 0 0x03 Ramp-up; accepted as MasterVolt enabled only when House is not on Shore/Generator
0x02140898 Byte 0 0x02 Ramp-down; accepted as MasterVolt disabled only when House is not on Shore/Generator
0x02060B88 Bytes 0..3 00 7C 7F FF → 00 7E 7F FF House AC transfer contactor status confirmation.

2.3 AC Voltage & Frequency Telemetry

Measurement CAN Frame ID Bytes Scaling Rate Range
House AC Line Voltage (Heartbeat) 0x00000B88 Bytes 2..3 (BE) uint16 Whole Volts Continuous 1 Hz 0 – 250 V
A/C Line Voltage (Heartbeat) 0x00000B90 Bytes 2..3 (BE) uint16 Whole Volts Continuous 1 Hz 0 – 250 V
House AC Extended Telemetry 0x02040B88 Bytes 4..5 (BE) uint16 Whole Volts Periodic / Event 0 – 250 V
A/C Extended Telemetry 0x02040B90 Bytes 4..5 (BE) uint16 Whole Volts Periodic / Event 0 – 250 V

3. D-Bus Integration Paths on Venus OS

3.1 Native Victron Device Services

The integration exposes physical AC hardware as native Victron D-Bus device services:

  1. com.victronenergy.inverter.scheiber_mastervolt (MasterVolt 2000W House Inverter • DeviceInstance 270):
    • /State: 9 while the inverter is enabled/running, 0 when a context-valid OFF transition is observed
    • /Mode: 2 (ON), 4 (OFF)
    • /Ac/Out/L1/V: House voltage only while the inverter is actually supplying the House bus; unavailable while Shore or Generator is selected
    • /Dc/0/Voltage: House battery supply voltage
  2. com.victronenergy.grid.scheiber_shore (Shore Power Transfer • DeviceInstance 41):
    • /Connected: 1 when Shore is applied to either panel with 80–300V line voltage, 0 in standby
    • /Ac/L1/Voltage: Measured Shore AC line voltage
  3. com.victronenergy.acsystem.scheiber_house (House source selector • DeviceInstance 42, receive-only):
    • /Ac/NumberOfAcInputs: 2
    • /Ac/In/1/Type: 3 (Shore)
    • /Ac/In/2/Type: 2 (Generator)
    • /Ac/ActiveIn/ActiveInput: 0 (Shore), 1 (Generator), or 240 (neither external input)
    • /Ac/In/1/L1/V and /Ac/In/2/L1/V: measured House-bus voltage on the active external input
    • /Scheiber/HousePanel* and /Scheiber/AcPanel*: both selectors' receive-only source and voltage diagnostics
  4. com.victronenergy.inverter.ttyS7 (Phoenix 12V 375VA • Starlink Inverter • DeviceInstance 279):
    • Dedicated VE.Direct inverter for Starlink connectivity

3.2 Scheiber Diagnostics & Power Distribution Paths

Under com.victronenergy.genset.scheiber on the Cerbo GX system bus:

D-Bus Path Type Example Values Purpose
/Scheiber/HousePanelAppliedSource int 1 (OFF), 2 (SHORE), 4 (GEN), 8 (INVERTER) Numeric source enum for House bus
/Scheiber/HousePanelAppliedSourceText string "OFF", "SHORE", "GENERATOR", "INVERTER" Human-readable House source
/Scheiber/AcPanelAppliedSource int 1 (OFF), 2 (SHORE), 4 (GEN) Numeric source enum for A/C bus
/Scheiber/AcPanelAppliedSourceText string "OFF", "SHORE", "GENERATOR" Human-readable A/C source
/Scheiber/MastervoltInverterState int 0 (OFF), 1 (ON) MasterVolt 2000W operating state
/Scheiber/MastervoltInverterStateText string "OFF", "ON" MasterVolt 2000W operating text
/Scheiber/MastervoltSupplyingHouse int 0, 1 Whether the House selector is actually taking inverter power
/Scheiber/MastervoltSupplyingHouseText string "NO", "YES" Human-readable House-supply role
/Scheiber/HousePanelVoltage float 230.0 V Measured House AC voltage
/Scheiber/AcPanelVoltage float 230.0 V Measured A/C AC voltage

4. Venus OS GUI-v2 Live Visualization

In Victron GUI-v2 (http://venus.local/gui-v2/), the AC topology is rendered dynamically:

Venus OS GUI-v2 Live AC Topology

  • Shore / Generator Tiles: The House selector drives the standard Venus two-input topology. GUI-v2 labels input 1 as Shore, input 2 as Generator, highlights the selected external input, and reads its measured line voltage. The Generator card also shows the connected-genset state and voltage, for example Running · 230 V.
  • MasterVolt Inverter Node: Reports inverting only while the inverter is actually feeding the House bus. Its enabled/standby fallback state does not override an applied Shore or Generator selection.
  • Control Cards: Tapping Controls/Cards displays Inverter (MasterVolt 2000W) and Inverter (STARLINK INV) as dedicated standalone tiles.

The stock Overview has one system-level active AC-input model, so it cannot draw the House and A/C selector panels as two independent transfer diagrams. The House selector is authoritative for Overview; the A/C selector remains visible through the diagnostic D-Bus paths and the Node-RED AC routing view.

5. Node-RED Real-Time Flow (AC Power & Inverter Routing)

The flow (cerbo/node-red-ac-power-flow.json) monitors all D-Bus paths and maintains a live power routing matrix:

{
  "summary": "House: INVERTER (230V) | A/C: OFF (0V) | Mastervolt 2000W: ON",
  "house": {
    "source": "INVERTER",
    "voltage_v": 230,
    "active": true
  },
  "air_conditioning": {
    "source": "OFF",
    "voltage_v": 0,
    "active": false
  },
  "mastervolt_inverter": {
    "state": "ON",
    "inverting": true
  }
}

This flow is automatically installed, staged, and merged non-destructively by install.sh.

Node-RED AC Power Routing Flow