Configuring Victron and Fronius for AC-Coupled PV Systems
Updated 8 September 2026 · By SolarNevs Research Desk, Dealer surveys + verified sources · 1 source · Method ↗
Key Takeaways
- Ensure both Victron and Fronius inverters are updated to their specified minimum firmware versions.
- Configure the Fronius inverter for the correct country-specific setup, typically MG50 or MG60.
- Use the ESS Assistant or PV Inverter support in Victron's VE.Configure software to manage frequency shifting.
- Some Fronius models require additional DataManager hardware for monitoring with Victron GX devices.
How do you set up Victron and Fronius in an AC-coupled system?
Setting up Victron MultiPlus or Quattro inverters with Fronius PV inverters for AC coupling involves specific configuration steps for both brands. The process requires updating firmware, selecting appropriate grid settings on the Fronius inverter, and configuring frequency control assistants within the Victron system. This ensures the PV inverter's output is managed correctly by the Victron inverter, especially in off-grid or battery-priority scenarios.
Compatible Fronius Inverters and Software Versions
Successful AC coupling between Victron and Fronius systems depends on using compatible Fronius PV inverter models with specific minimum firmware versions. These requirements ensure proper communication and frequency control.
Compatible ROW Inverters (European Type AC Grid)
Model | Ratings | Software Version |
|---|---|---|
Fronius Primo | 1~, 3 kW up to 8.2 kW | |
Fronius Symo | 3~, 3 kW up to 20 kW | |
Fronius Eco | 3~, 25 kW or 27 kW | |
Fronius Agilo | 3~, 75 kW up to 100 kW | |
Fronius IG Plus V | 1~, 2~, 3~, 2.5 kW up to 12 kW | |
Compatible UL Inverters (US Type AC Grid)
Model | Ratings | Software Version |
|---|---|---|
Fronius Primo UL | 1~, 3.8 kW up to 15 kW | |
Fronius Symo 10-24 480V | 3~, 10 kW up to 24 kW | |
Fronius Symo 10-15 208-240V | 3~, 10 up to 15 kW | |
Configuring Your Fronius PV Inverter
Before connecting your Fronius inverter to a Victron system, it requires specific setup steps to ensure compatibility and correct operation.
- Update Firmware: Make sure the Fronius PV inverter is updated to at least the firmware version mentioned in the compatibility table above. Refer to Fronius documentation for firmware update procedures.
- Initial Setup: After making the inverter operational according to its manual, select the language.
- Country-Specific Setup: Choose the country-specific setup. Here, select
MG50orMG60depending on your system's frequency (50Hz or 60Hz). - Start Up: The inverter is now ready to start up.
Configuring Your Victron MultiPlus or Quattro Inverter
The Victron MultiPlus or Quattro inverter needs to be configured to manage the AC-coupled Fronius PV inverter, primarily through frequency shifting.
- Connect to VE.Bus: After connecting the MultiPlus or Quattro with the battery, connect a computer through the VE.Bus port. This typically requires a Victron interface like the MK2USB.
- Use VE.Configure: Configure the system using the latest version of the VE.Configure software.
- Access Assistants: Go to the "Assistants" tab within VE.Configure.
- Add Assistant: Add one of the Assistants that regulate output frequency. This will typically be the "ESS Assistant" or "PV Inverter support" assistant.
- Default Settings: It is generally not necessary to change the default settings in the Assistant, but review them for any specific system requirements. Consult the ESS Design and Installation Manual for detailed exceptions.
- Complete and Write Settings: Complete the rest of the Assistant configuration and write the new settings to the MultiPlus or Quattro.
Victron Multi/Quattro Frequency Shift Settings
The Victron MultiPlus or Quattro controls the Fronius PV inverter's output by shifting the AC frequency. The following table outlines the typical frequency thresholds for 50Hz and 60Hz systems.
State | 50Hz (Hz) | 60Hz (Hz) |
|---|---|---|
Start | 50.2 | 60.2 |
Minimum | 52.7 | 62.7 |
Disconnect | 53.0 | 63.0 |
Note: For Fronius bundles between fro35020 and fro36120, the disconnect frequency for the Victron MultiPlus or Quattro should be set to 53.1 Hz for 50Hz systems and 63.1 Hz for 60Hz systems. Problems when reconnecting to the grid can occur if these specific Fronius bundles hold the inverter relay closed up to 53Hz for MG50, or 63Hz for MG60.
Monitoring Fronius PV Inverters with Victron GX Devices
To monitor your Fronius PV inverter's performance through a Victron GX device (like a Cerbo GX) and the VRM Portal, some Fronius models require additional hardware.
Model | Required accessory |
|---|---|
Fronius Symo Light | Purchase and install the |
Fronius Symo | No accessory needed, datamanager card installed from factory |
Fronius Galvo | No accessory needed, datamanager card installed from factory |
Fronius Primo | No accessory needed, datamanager card installed from factory |
Fronius Eco | No accessory needed, datamanager card installed from factory |
Fronius IG Plus | Purchase and install the |
Fronius Agilo | Purchase and install the |
Fronius GEN24 | Special procedure for limitations and LAN configuration applies |
Safety Considerations for AC-Coupled Systems
When integrating PV inverters, specific safety guidelines must be followed. For transformerless inverters like the Fronius Primo, Symo, and Eco, PV modules that require pole-grounding (on the Plus or Minus pole) cannot be connected. Always consult the specific manuals for both Victron and Fronius for comprehensive safety instructions.
When to call a technician instead
Configuring AC-coupled PV systems involves working with high voltages and complex settings. If you are unsure about any step, particularly regarding electrical connections, firmware updates, or software configurations, it is advisable to consult a qualified solar technician. Incorrect wiring or settings can damage equipment, void warranties, or create safety hazards. Professional assistance ensures the system is installed and configured safely and efficiently.
Frequently asked questions
What Fronius inverters are compatible with Victron AC coupling?
Compatible Fronius inverters include Primo, Symo, Eco, Agilo, and IG Plus V for European grids, and Primo UL, Symo 10-24 480V, and Symo 10-15 208-240V for US grids. Each model requires a specific minimum firmware version for proper operation.
What firmware is required for Fronius inverters in a Victron AC-coupled system?
Fronius Primo, Symo, and Eco require firmware version `//fro27140.upd//` or higher. Fronius Agilo needs `//update19.tl//` or higher. Fronius IG Plus V requires `//IGF 5.0.66//` or higher with specific Victron settings. Fronius Primo UL needs `//fro27470.upd//` or higher.
How do Victron inverters manage Fronius PV output in an AC-coupled system?
Victron MultiPlus or Quattro inverters use frequency shifting to manage PV output. They adjust the AC frequency, causing the Fronius inverter to reduce its power output. This is configured using the ESS Assistant or PV Inverter support in VE.Configure.
What are the Victron frequency settings for a 50Hz system?
For a 50Hz system, the Victron MultiPlus or Quattro typically starts frequency shifting at 50.2 Hz, reaches a minimum frequency of 52.7 Hz, and disconnects the PV inverter at 53.0 Hz. For Fronius bundles between `fro35020` and `fro36120`, the disconnect frequency is 53.1 Hz.
Do I need extra hardware to monitor Fronius inverters with Victron GX devices?
Some Fronius models, like Symo Light and IG Plus, require purchasing and installing a `datamanager 2.0`. Fronius Agilo requires a `datamanager box`. Other models such as Symo, Galvo, Primo, and Eco have the datamanager card installed from the factory and require no additional accessory.
References
- Victron Energy AC Coupling with Fronius — accessed 23 August 2026
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