How to connect FOX ESS G-Max C&I hybrid inverter with Reduxi controller
Connect a FOX ESS G-Max C&I hybrid inverter to the Reduxi Controller via Modbus TCP/IP, activate remote control on the inverter and add it in the Configurator.
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Photo (product render) of a tall white cabinet, seen at an angle on a purple gradient background with a reflective floor. The logo 'FOX ESS' is printed at the top left of the front door, with three short cyan dashes below it. A small red round button or marking with tiny text is on the right of the upper door. The lower part of the front has a hexagon-pattern ventilation grille and a dark base plinth. Both doors have a small vertical handle on the left edge.
1 Technical documentation
The FOX ESS G-Max is a C&I hybrid inverter. The Reduxi Controller communicates with it over the local network via Modbus TCP/IP, reads the measured values and sends the commands of the Reduxi strategies. The settings on the inverter are made directly on its interface.
Manufacturer documents:
- FOX ESS website – product information and contact (web, EN)
- FOX ESS downloads – datasheets, manuals and other documents (web, EN)
2 Required equipment
- Reduxi Controller (installed and online)
- FOX ESS G-Max hybrid inverter, commissioned
- LAN connection of the inverter to the same network as the Reduxi Controller (router or switch)
- Access to the inverter interface to change the network settings and the control type
- Laptop or tablet with internet access to configure the device in Reduxi
3 System overview & wiring
The Reduxi Controller and the inverter communicate over the local network. No extra gateway is needed. The router also connects the system to the internet.
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Diagram of the network connection. Top left: the Reduxi controller (dark grey box with the reduxi logo, label 'Controller'), with an Ethernet cable (cyan line, label 'Ethernet') going down to a Wi-Fi router (label 'Router'). From the router a second cyan line labelled 'Ethernet' goes right to a tall white cabinet with the logo FOX ESS and the marking G-MAX (the FOX ESS G-Max). From the router a dashed cyan line goes down to a globe icon with the text 'WWW' at the bottom left (internet).
| Connection | From | To | Note |
|---|---|---|---|
| LAN (Modbus TCP/IP) | Reduxi Controller | Router / switch | Same network as the inverter |
| LAN (Modbus TCP/IP) | FOX ESS G-Max | Router / switch | Port 502, static IP address |
| LAN | Router | Internet | Needed for the Reduxi Cloud and the app |
4 Configure the inverter
Two settings on the inverter are needed before Reduxi can connect. Both are made directly on the inverter interface.
4.1 Set a static IP address
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Photo of a dark touchscreen of the FOX ESS G-Max (logo 'FOX' partly visible at the bottom), showing a network settings page with reflections on the glass. Three blocks: eth0 (marked with a red rectangle), eth1 and eth2. eth0 fields: DNS address (blacked out), IP address (blacked out), Subnet mask (blacked out), Default gateway (blacked out), MAC address (blacked out), Target IP address1 (blacked out), Subnet mask1 (blacked out), Priority: 0, Target IP address2 (blacked out), Subnet mask2 (blacked out), Priority: 0. eth1 fields: DNS address (blacked out), IP address (blacked out), Subnet mask (blacked out), Default gateway (empty), MAC address: f0:22:1d:a4:4a:1(last character cut off). eth2 fields: DNS address (blacked out), IP address (blacked out), Subnet mask (blacked out), Default gateway (empty), MAC address: f0:22:1d:a4:4a:1f. A teal button 'Return to Home' is at the bottom left.
4.2 Activate remote control
5 Log in to the Reduxi web interface
The device is added in the Configurator, the web interface of the Reduxi Controller. You do not add it in the Reduxi app itself or in the Reduxi Cloud. You can open it in two ways:
Recommended
http://reduxi.local.Text description of this image
Screenshot of three Reduxi mobile app screens side by side, with cyan boxes and number badges 2 to 4. Left screen (dashboard, dark theme): menu icon at top left marked with a box and badge 2; 'reduxi' logo; tabs 'Real time data' (active) and 'Statistics'; price 5.79 € and temperature 3.2 °C; energy flow diagram with a house in the centre (-1.25 kW) and icons with values 69.0 W, 1.3 kW, 1.1 kW (red ring), -165.0 W with 97 % (red ring) and 0.0 W values at the bottom; tabs 'Power' and 'Energy'; bottom navigation: Dashboard, Diagnostics, Device control, Settings. Middle screen (side menu): 'reduxi' logo, 'Number of locations: 1233', heading 'Reduxi device management', entries '+ Add Reduxi location' and 'Reduxi devices' (marked with a box and badge 3), then 'My profile' and 'About app'. Right screen (device page): Back; picture of a black Reduxi controller with two Ethernet ports; status 'Connected'; card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'; card 'Connect to configurator': 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' with button 'Activate tunnel connection' (marked with a box and badge 4); card 'Unit details' with field 'Unit ID'.
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Screenshot made of two parts side by side. Left part: Reduxi mobile app screen on a dark background. Top: Back button; picture of a black Reduxi controller with two Ethernet ports and a terminal block; status 'Connected' with a Wi-Fi icon. Card 'Update available': 'New update is available for your Reduxi device.' with button 'Download and install update'. Card 'Connect to configurator' with a key icon: 'Tunnel connection enables remote access to your Reduxi configurator, without need to be connected to the same local network.' and button 'Open configurator', marked with a cyan box and number badge 5. Below: card 'Unit details' with a field 'Unit ID' (value not visible). Right part: Reduxi Configurator opened in a browser, marked with a cyan frame and number badge 6. Header: back arrow, 'Tunnel connection', reload icon. Left sidebar with icons (lightning, chip, lightning bolt, bar chart, gear). Page 'Home' with a green link icon. Green notice: 'New patch available. Click here to apply.' with a close X. Time 09:12:56. Energy flow diagram with a house in the centre (1.700 kW) and icons for grid (0.000 kW), solar (1.700 kW), battery (green, 0.000 kW and 0.800 kW), a device at left (0.900 kW), electric vehicle and a charger or device at bottom. Label 'Energy manager' at the bottom.
reduxi.app) open the location, then Manage location → OEM devices → Activate tunnel connection, confirm with OK and wait about 30 seconds. Then click Go to controller. The Configurator opens in a new tab without a password.http://reduxi.local. The IP address is in the router's device list or in the app under Reduxi devices.admin · Password admin (factory default). If it was changed during installation, use that one. This is not your Reduxi account password.Text description of this image
Screenshot of the Reduxi Configurator login page in a Chrome browser window. The address bar shows 'Not secure' and 'reduxi.local'; the address bar is marked with a cyan box and an enlarged copy of it (cyan box, text 'Not secure reduxi.local') is shown at the left, connected by a cyan line. Page background: light grey line drawing of a house with solar panels (green), a wall box, an inverter, a car and a charger. Top left: 'reduxi configurator' logo. Login box in the centre with title 'Login', a language selector (English flag, 'English'), a username field and a password field, and a dark 'Login' button.
This is what you should see:
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Screenshot of the Reduxi Configurator Home page. Left menu with the reduxi Configurator logo; section Devices (expanded) with entries Kostal Plenticore G2 IP=131, Kostal Plenticore G2 IP=133 and P1 WiFi / Ultra, then buttons Add device and Add EEBUS device; below: Strategies (+), Utility Rate Plan, Settings (+). Top bar: title Home, green link icon and green cloud icon at the right. Main area: time 14:53:27 and an energy flow diagram with a centre house showing 6.700 kW, Grid 0.000 kW, Solar 6.700 kW, Other 3.000 kW, Battery storage 0.000 kW and 3.700 kW, EV charger (dash) and HVAC (dash). Small footer text at the bottom right.
admin login is not your Reduxi account. reduxi.local only works in the same network as the controller.6 Add the device to Reduxi
Open the Configurator first, see Point 5. The device is added with the wizard in two steps.
6.1 Basic settings
FOX ESS G-Max. Tick the strategies the inverter should take part in, then click Next.Text description of this image
Screenshot of the device list in the left menu of the Reduxi Configurator. Heading 'Devices'. Rows, top to bottom (each with a small icon that is barely visible): Heizstab Wärmepumpe; Iskraemeco AM550; Ochsner GMLW 9Plus; SolarEdge; SolarEdge Slave; Zaptec PRO; myPV. Below the list two buttons: '+ Add device', marked with a red rectangle, and '+ Add EEBUS device'.
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Screenshot of the Reduxi Configurator add device wizard, 'Basic settings'. Step indicator at the top: step 1 and step 2 (circle 2 labelled 'Communication channel'). Device type *: Hybrid inverter (greyed text). Type *: FOXESS G -MAX (selected tag). Name *: FOX ESS G-MAX. 'Include to strategy' table with columns Strategy, Measurement devices, Regulated devices; row 'Energy manager new': both checkboxes ticked. Buttons: Back (left), link 'How to configure?' and Next (right, black).
6.2 Communication settings
The second step sets up the communication channel for Modbus TCP/IP between the Reduxi Controller and the inverter.
| Parameter | Value |
|---|---|
| Connection | TCP/IP |
| IP | IP address of the FOX ESS G-Max (the static address from Point 4.1). Scan for IP can search for it in the network. |
| Port |
502 (default) |
| Extended IP recovery | Leave switched on (default) |
| Modbus unit ID | The same ID as set on the inverter (default 1) |
| Rated power of inverter | According to the inverter (default 100 kW) |
| Is electricity meter installed? / Is PV installed? | Set according to your system (both are on by default) |
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Screenshot of the Reduxi Configurator add device wizard, step 2 of 2 (two numbered circles at the top, circle 2 is the current step). Section title: 'Communication channel and device configuration'. Connection *: TCP/IP. IP *: empty, with a black button 'Scan for IP'. Port *: 502. Extended IP recovery (with info icon): toggle Yes (on). Modbus unit ID *: 1. Rated power of inverter *: 100, unit kW. Is electricity meter installed?: toggle Yes (on). Is PV installed?: toggle No (off); hint: 'PV (monitoring only): Measurements only; active power setpoint cannot be written'. Buttons at the bottom: Back (left), link 'How to configure?', Test communication and Done (black).
6.3 Test communication
Click Test communication at the bottom of the wizard. It checks the Modbus TCP/IP connection once and saves nothing. If the result is fine, click Done. Only Done creates the device.
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Screenshot of the bottom button bar of a Reduxi Configurator page. Left: button 'Back'. Right: button 'Test communication' (marked with a cyan box) and dark button 'Done'.
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Screenshot of the Reduxi Configurator page 'Communication channel and device configuration'. Connection *: TCP/IP (dropdown). IP *: 192.168.50.243, with button 'Scan for IP'. Port *: 502, with button 'Test port'. Modbus unit ID *: 1. Buttons at the bottom: Back (left), Test communication and Done (right). The Done button is marked with a cyan box.
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Screenshot of a Test communication dialog in the Reduxi Configurator (close X at top right, dark Close button at bottom right). Green text in a white box: Successful readout from device. Battery active power: 330.0 W; Battery current: 0.9952 A; Battery export active energy: 740760.0 Wh; Battery import active energy: 765890.0 Wh; Battery max. active power: 8210.0 W; Battery max. state of charge: 100 %; Battery min. active power: -9131.0 W; Battery min. state of charge: 0.0 %; Battery state name: CHARGING null; Battery state of charge: 33.8 %; Battery state of health: 100.0 %; Battery temperature: 23.1 °C; Battery voltage: 331.6 V; Error: false null; Grid active power: 5.0 W; Grid export active energy: 1588740.0 Wh; Grid frequency: 50.01 Hz; Grid import active energy: 0.0 Wh; Grid state name: METER_ONLINE null; Inverter active power: -441.0 W; Inverter max. power: 10000.0 W; Inverter min. power: -10000.0 W; Load active power: 446.0 W; Load import active energy: 0.0 Wh; Model name: SigenStorEC100TP null; PV active power: -963.0 W; PV current: -1.99 A; PV export active energy: 0.0 Wh; PV min. active power: -10000.0 W; PV state name: CONNECTED null; PV voltage: 322.3 V; State name: RUNNING null. Additional parameters: BATTERY_CAPACITY_MAX_WH: 16120.0; BATTERY_CAPACITY_WH: 5448.56; GRID_EXPORT_POWER_ACTIVE: 0.0; GRID_IMPORT_POWER_ACTIVE: 5.0; GRID_POWER_ACTIVE_L1: 0.0; GRID_POWER_ACTIVE_L2: 5.0; GRID_POWER_ACTIVE_L3: 5.0 (partly cut off in the image); PV_POWER_ACTIVE_MAX: 0.
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Screenshot of the Reduxi Configurator dialog 'Test communication' with a close X at the top right and a black 'Close' button at the bottom right. Text in red: 'Unable to communicate with device.' Details box in red: 'Unable to communicate with 192.0.2.10 on port 502. Check if service is enabled on device, port number is correct and device is reachable on the network.' Then: 'PING 192.0.2.10 (192.0.2.10) 56(84) bytes of data.' and '--- 192.0.2.10 ping statistics ---' and '2 packets transmitted, 0 received, 100% packet loss, time 1064ms'.
7 Check the readings
7.1 Check the readings
Open Devices → FOX ESS G-Max → Last measurements. The values show whether the inverter communicates correctly.
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Screenshot of the Reduxi Configurator 'Last measurements' page of a device. Tabs: Last measurements (active), Analyze, Archive. Top right: refresh dropdown 'Without refreshing' and a refresh button. Card 'Control type': buttons Auto (light green) and Manual (dark, selected); timestamp 14. 03. 2025 12:49:13. All values below have timestamp 14. 03. 2025 12:49:01 unless noted. Card PV: PV active power -1.0 kW; PV current -1.98 A; PV voltage 327.63 V; PV export active energy 587.0 kWh; PV min. active power -10.0 kW; PV export active power limit: empty (unit kW); enumeration.PV_STATE_NAME: CONNECTED. Card Load: Load active power 0.4 kW; Load import active energy 1,109.2 kWh. Card Battery: Battery active power 0.4 kW; Battery current 1.09 A; Battery voltage 331.60 V; Battery state name CHARGING; Battery state of charge 33.80 %; Battery min. state of charge 0.00 %; Battery max. state of charge 100.00 %; Battery import active energy 765.9 kWh; Battery export active energy 740.8 kWh; Battery min. active power -9.1 kW; Battery max. active power 8.2 kW; Battery active power setpoint 1.0 kW. Card Inverter: Inverter active power -0.4 kW; Inverter max. active power 10.0 kW; Inverter min. active power -10.0 kW; State name RUNNING; Error OFF. Card Grid: Grid frequency 49.990 Hz; Grid active power 0.0 kW; Grid import active power limit: empty (kW); Grid export active power limit: empty (kW); enumeration.GRID_STATE_NAME METER_ONLINE; Grid export active energy 1,588.7 kWh; Grid import active energy 0.0 kWh. Card Other: Battery state of health 100.00 %; Battery temperature 23.10 °C; Model name SigenStorEC100TP; Communication error OFF (timestamp 12:48:56); Control type MANUAL; Mode name setpoint SELF_CONSUMPTION.
7.2 Control behaviour
For control by the Reduxi strategies, open Devices → FOX ESS G-Max in the Reduxi Configurator and set the control type to AUTO. Only then do the strategy commands affect the battery.
To reduce energy costs with dynamic prices and tariffs, define the strategy as described in Strategies for Reduxi controller. After the device has been added, you can monitor and control it in the Reduxi application.
✓ Summary
Preparation (Points 1–3): Check the manufacturer information, connect the Reduxi Controller and the inverter to the same network and note the IP address of the inverter.
FOX ESS G-Max (Point 4): Set a static IP address and activate remote control on the inverter.
Add to Reduxi (Points 5–6): Open the Configurator, add a Hybrid inverter of type FOX ESS G-Max, enter IP, port 502, unit ID and rated power, run Test communication and click Done.
Go live (Point 7): Check the last measurements and set the control type to AUTO so that the strategies can control the battery.
→ Common issues
| Issue | Solution |
|---|---|
| Test communication fails | Check that the IP address in Reduxi is the current address of the inverter, the port is 502 and the unit ID matches the inverter (default 1). Controller and inverter must be in the same network, and remote control must be active on the inverter (Point 4.2). |
| The device goes offline after some time or after a router restart | The IP address of the inverter has probably changed. Set a static IP address on the inverter or a DHCP reservation in the router (Point 4.1) and enter the new address in Reduxi. |
| Strategy commands have no effect on the battery | Set the control type of the device to AUTO in the Configurator (Point 7.2) and check that remote control is active on the inverter. |
| Open configurator does not open or stays empty | The tunnel is not active yet. Wait about 30 seconds and check that the controller is online. |
Login with admin is rejected |
The password was changed during installation. Ask the installer. The Reduxi account password does not work there. |
reduxi.local does not load |
You are not in the same network. Use the IP address or the tunnel. |
| Communication test fails, device offline | Check reachability, IP, port 1502 and unit ID 71, and that Modbus is enabled on the inverter. |