How to connect Sungrow inverters and ST batteries with Reduxi controller
Connect Sungrow string inverters, hybrid inverters and ST batteries to the Reduxi Controller via Modbus TCP/IP (WiNet-S/S2, Data Logger or LC300) for maximum flexibility and lower energy costs.
1 Technical documentation
Manufacturer manuals for the Sungrow communication devices:
- User manual WiNet-S/S2 – Dongle for Wi‑Fi or LAN connection of the inverter
- User manual Data Logger 1000 – Logger for LAN connection of the inverters
- User manual Data Logger 4000 – See chapter 2.2 of the manual
- User manual LC300 – Local controller for the ST battery series
2 Supported devices and required equipment
2.1 Supported Sungrow devices
The connection method depends on the device type:
| Type | Models | Connection type |
|---|---|---|
| Sungrow String Inverter 3p | SGXXX-XX Series | WiNet-S/S2 (see Point 3) Data Logger (see Point 3) |
| Sungrow Hybrid Inverter 3p | SH Series | WiNet-S/S2 (see Point 3) Data Logger (see Point 3) |
| ESS C&I | STXXX kWh series / Power stack | Sungrow LC300 Local Controller (see Point 4) |
2.2 Required equipment
- Reduxi Controller
- Sungrow string or hybrid inverter, or ST battery (ESS C&I)
- WiNet-S/S2 dongle, Data Logger 1000/4000 or LC300 (depending on the device)
- Ethernet cable (RJ45)
- Laptop or tablet with internet access to configure the device in Reduxi
3 Connect the string or hybrid inverter
3.1 Connection through the WiNet-S/S2 dongle
The WiNet-S/S2 dongle connects the inverter to the local network via Wi‑Fi or LAN.
3.2 Install the WiNet-S/S2 on the inverter
The pictures show the generic installation of the WiNet on a Sungrow inverter, first with WLAN communication, then with LAN communication. For details, see the manuals in Point 1.
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Diagram titled Installation with WLAN communication. Two numbered panels. Panel 1: a hand holds an orange dongle part against the underside of a wall-mounted inverter (white box with connectors at the bottom), a blue arrow shows the insertion direction. Panel 2: the white dongle with a round threaded connector and a small indicator panel; an orange cap above it with the word Click and a blue arrow pointing up.
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Diagram titled Installation with LAN communication, five numbered steps. Step 1: cable labelled CAT 5E, diameter 5.3...7mm; an RJ45 plug; a 40mm stripped length with a Protection cap on the cable; two small wiring tables labelled TIA/EIA 568A and TIA/EIA 568B with pins 1 2 3 4 5 6 7 8 and coloured wires; ticks mark the correct parts. Step 2: the white dongle with a threaded connector, a blue curved arrow shows turning the connector nut. Step 3: the cable parts (nut, seal, protection cap) are threaded onto the cable and pushed toward the dongle, blue arrow. Step 4: a hand holds the orange part against the underside of the inverter. Step 5: the assembled dongle with an orange cap, the word Click and a blue arrow pointing up.
3.3 Open Modbus TCP locally on the WiNet-S/S2
Reduxi can only communicate with the Sungrow inverter if Modbus TCP is enabled on port 502. You can set this locally in the WiNet web interface (this point) or in the iSolarCloud web app (see Point 3.4).
- Connect to the WiNet-S/S2 web interface.
- Go to System – Forwarding Configuration and enable port 502.
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Screenshot of the WiNet-S2 web interface, Forwarding Configuration page. Left menu: Overview, Device Monitoring, Device, History Data, System (expanded; entries Run Information, System Maintenance, Message Export, System Time, Forwarding Configuration highlighted in orange, Port Parameter, More), About. Top bar: error and warning counters, Setup Wizard, English, admin. Tabs: iSolarCloud, MODBUS (selected, orange), Third-party Portal. Sub tab: Server. Button at the right: White List Setting. Table columns: Local Port, Switch, SSL Encryption. Row 1: Local Port 502; Switch: on (orange toggle, marked by a red arrow); SSL Encryption: off (greyed toggle). Row 2: Local Port 510; Switch: on; SSL Encryption: on.
To find the Modbus unit ID of the inverter, go to Device – Device List and check the Forwarding Modbus ID of the inverter.
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Screenshot of the WiNet-S2 web interface, Device List page. Left menu: Overview, Device Monitoring, Device (expanded; entries Device List highlighted in orange, Firmware Update, Inverter Log, AFCI Activation, Fault Recorder), History Data, System, About. Top bar: error and warning counters, Setup Wizard, English, admin. Buttons: Auto Detect, Add Device, Delete. Table columns: No, S/N, Device Name, Device Model, Port, Device Address, Forwarding Modbus ID, Com Status, Action. Row 1: No. 1; S/N A2011511015; Device Name SH10RS(COM1-002); Device Model SH10RS (red box); Port COM1; Device Address 2; Forwarding Modbus ID 3 (red box); Com Status green link icon. Row 2: No. 2; S/N; Device Name SBH200-V11(COM1-200); Device Model SBH200-V11; Port COM1; Device Address 200; Forwarding Modbus ID 4; Com Status green link icon.
3.4 Open Modbus TCP via the iSolarCloud web app
- Log in to the iSolarCloud web app on your computer.
- Go to Settings – Device parameters – Common Settings of the WiNet dongle.
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Screenshot of the iSolarCloud web app, Settings, Device parameters (very small text). Left menu: Overview, Device, Fault, Curve, Settings (highlighted by a red box), Plant configuration, Firmware update. Top tabs: Quick setting and Device parameters (Device parameters highlighted by a red box). Filter row: dropdown Communication module, dropdown Device model, a Device S/N field and a Search button; at the right a button Common settings (red box). Table columns: checkbox, Plant name, Device name, Device S/N, Device model, Device location, Action. One row is shown: Plant name, Device name: Communication Module, Device S/N, Device model: WiNet-S, Device location, two action icons.
In the common settings of the WiNet dongle, set Modbus TCP 502 Port on/off to open.
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Screenshot of an iSolarCloud settings table titled Common settings. Columns: No., Parameter name, Value. Rows: 1 AP hotspot (Please select); 2 O&M (Please select); 3 Update to previous (or same) version (Please select); 4 Reset login password (Please select); 5 Modbus TCP 502 port on/off (name in a red box; dropdown open, options Please select, Open, Disable; Open is highlighted by a red box); 6 Remote device restart (Value hidden behind the open dropdown).
3.5 Connection through Data Logger 1000/4000
For details, see the Sungrow documentation for Data Logger 1000 and Data Logger 4000.
Step 1. Connect the Data Logger to the inverters with an Ethernet cable (RJ45).
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Image titled Communication cable specification with a table: Cable: RJ45 communication cable; Type: Shielded twisted pair Ethernet cable. Text: step 1 Lead the RJ45 communication cable from the inverter to the wiring area of Logger1000. step 2 Strip the insulation layer of the communication cable with an Ethernet wire stripper, and lead the corresponding RS485A/B signal cables out. Insert cord end terminals into signal cable RS485+ A and signal cable RS485- B, and crimp them with a crimper. Cut off the redundant signal cable and warp it with a heat-shrink tubing. If the communication cable is Shielded Ethernet cable, white-green wire 3 is defined as RS485- B wire and the green wire 6 as RS485+ A wire. Below: a drawing of an RJ45 plug on a black cable with two thin wires labelled RS485+ A and RS485- B; an RJ45 Port pin diagram numbered 12345678 with a pin colour list (Pin 1 White-orange; Pin 2 Orange; Pin 3 White-green; Pin 4 Blue; Pin 5 White-blue; Pin 6 Green; Pin 7 White-brown; Pin 8 Brown); boxes RS485+ A and RS485- B; a small note that pins used for communication are Pin 3 to RS485-B and Pin 6 to RS485-A (small print).
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Image with two instruction steps from a manufacturer guide. Step 3: text Connect the communication cable to the RS485 ports of the Logger1000, as shown in the figure below. Below it three drawings left to right joined by blue arrows: a Logger1000 DIN-rail unit with a terminal block and a screwdriver at a terminal, a close-up of the terminal block with the wire inserted and screwdriver tightening (numbered markers 1 and 2), and the terminal block with the wires fitted. Step 4: text Connect the Logger1000 to the inverter. Drawing: a box labelled Logger1000 at the left with two removable terminal blocks, a large white box labelled Inverter at the right, and a black cable line running from the terminal blocks of the Logger1000 around the bottom to the underside of the inverter.
Step 2. Connect the Data Logger 1000/4000 to the Reduxi Controller with an Ethernet cable.
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Diagram on a white background. Left: a small light grey DIN-rail device labelled Logger1000. Centre: a black and grey network switch with 8 ports labelled Core Switch. Right: a black rounded box with the reduxi logo (lightning bolt and the word reduxi) and a connector on its left side. Connections: a black cable with RJ45 plugs runs from the Logger1000 to the Core Switch; a second black cable with RJ45 plug runs from the Core Switch to the reduxi box.
4 Connect the ESS C&I (ST battery series) through the LC300
4.1 Connect the LC300 to the battery and the Reduxi Controller
Connect the LC300 on the ST battery directly to the Reduxi Controller through Ethernet. The figure shows the positions of the Ethernet communication ports.
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Drawing of a tall, narrow cabinet (battery cabinet) seen from the front, with a large empty front panel and a base at the bottom. Near the bottom left a connection area with terminals and small components. A rounded orange-outlined callout at the lower right shows an enlarged grey connector block with four stacked Ethernet (RJ45) sockets, with labels beside it: Network port 1, Network port 2, Network port 3, Network port 4 (top to bottom). A thin line links the callout to the small port block in the cabinet's bottom area.
4.2 Set the communication parameters
Log in to the LC300 web interface and go to Parameter Settings – Comm Parameters. Make sure the IP address, Subnet mask and Gateway match the local network for Ethernet.
The Modbus port is set to 502 and is open by default, as the pictures show. Save the settings.
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Screenshot of the LC 300 web interface, network parameters page. Left menu: Running info (Summary info, PCS info, Battery system, Rack info, Combustible gas detecting device info, Temp ctrl device info), Parameters settings (highlighted by a red box; sub entries Running parameters, System parameters, Node parameters, and a red-boxed entry below, partly cut off). Top right: Personal center. Section Network port parameters(ETH2) with a Set button: IP address, Subnet mask, Gateway in a red box (subnet mask looks like 255.255.255.0). Section Network port parameters(ETH1) with a Set button: IP address: 192.168.1.100; Subnet mask: 255.255.255.0; Gateway: 192.168.1.1 (in a red box). Section Port settings with a Set button: HTTP port num: 80 (range shown in brackets).
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Screenshot of the LC 300 web interface, communication parameters page (text is very small). Left menu with Running info, Parameters settings (sub entries, one highlighted in orange), Device config, Protocol config, System info and others. Top right: Personal center. Sections from top: Network port parameters(ETH2) with a Set button; Network port parameters(ETH1) with the IP address, Subnet mask, Gateway fields inside an orange box; Automatic access with a red note about enabling the auto access function and two dropdowns; Port settings with a field for a port number and a dropdown on the right; Modbus parameters with a table (columns include Channel No, Port num, Operation) and the Port num field inside an orange box; below it a further section (IEC104 parameters). Set buttons are orange on each section.
4.3 Set the system parameters
Go to System Parameters and set the local/remote setting to Local/Remote. Change the time setting to Web Time Synchronization and set the time manually.
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Screenshot of the LC 300 web interface, System parameters page. Left menu: Running info (Summary info, PCS info, Battery system, Rack info, Node info, Combustible gas detecting device info, Temp ctrl device info), Parameters settings (Running parameters, System parameters highlighted in orange, Node parameters, Comm parameters, Sub device parameters), Device config. Top right: Personal center. Section Time settings with a Set button: Clock source: NTP time synchronization; Server IP:; Select timezone: (UTC+01:00) Amsterdam, Berlin, Rome, Paris. A red-outlined box around these fields contains red text: Change this to Web time Synchronization and set time manually. Section Local/Remote settings with a Set button: Local/Remote with options Local/Remote (selected, orange, inside an orange box), Remote, Local. Section Device type settings with a Set button: Access device selection: Combustible gas detecting device (ticked), Composite detector (not ticked), a third option, Dehumidifier (not ticked); Temperature controller device: one option.
5 Log in to the Reduxi web interface
You can open the Reduxi web interface in two ways:
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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.
http://reduxi.local. You can find the controller's IP address in your router's device list or in the Reduxi app under Reduxi devices.admin · Password: admin (factory default)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.
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Screenshot of the Reduxi Configurator web interface after login, light theme. Top left: 'reduxi configurator' logo. Header bar: 'Home' at left, green 'Connected' status at top right. Left sidebar: expanded section 'Devices' with a list of entries, then collapsed sections 'Manager' and 'Configuration' and 'Settings'. Main area: energy flow diagram. House in the centre with ring, value 24.20 kW. Grid icon at top left, 24.20 kW (red dot on its line). Solar icon at top right, value '-'. Left icon (battery or device), 6.700 kW (green dot on its line). Right icons (battery storage and a device), values '-'. EV charger icon at bottom left, 31.00 kW. A further device icon at bottom right. Label 'Energy manager' below the house.
6 Add the Sungrow device to Reduxi
Use these steps to add a new Sungrow device or to edit an existing one.
6.1 Basic settings
Log in locally to the Reduxi Configurator on the controller (see Point 5) and click + Add device.
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Screenshot of the top of the Reduxi Configurator left menu. Logo: reduxi Configurator. Devices (expanded, minus sign) contains only the button + Add device (framed). Below: Strategies (+), Utility Rate Plan, Settings (+).
In the first step, define the basic settings.
Sungrow string or hybrid inverter
- Device type:
Solar Power PlantorHybrid, depending on the system - Type:
Sungrow string/hybrid inverter 3p - Name: a name of your choice
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Screenshot of the Reduxi Configurator wizard, step 1 Basic settings (step 2 is Communication channel, greyed). Heading: Basic settings. Fields: Device type *: Solar power plant (dropdown); Type *: Sungrow String Inverter 3P (dropdown); Name *: Sungrow String Inverter 3P (text field). Buttons: Back (left), Next (right, dark).
Sungrow ESS C&I (ST battery series)
- Device type:
Battery - Type:
Sungrow ST - Name: a name of your choice
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Screenshot of the Reduxi Configurator wizard, step 1 Basic settings (step 2 is Communication channel, shown greyed). Heading: Basic settings. Fields: Device type *: Battery (dropdown); Type *: Sungrow ST (dropdown); Name *: Sungrow ST (text field). Buttons: Back (left), Next (right, dark).
Click Next.
6.2 Communication settings
In the second step, define the communication channel between the Reduxi Controller and the Sungrow device.
Sungrow string or hybrid inverter
| Parameter | Value |
|---|---|
| Connection | TCP |
| IP | IP address of the inverter |
| Modbus ID | The Modbus ID from the WiNet-S/S2 or Data Logger (see Point 3) |
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Screenshot of the Reduxi Configurator wizard, step 2 Communication channel (step 1 is Basic settings). Heading: Communication channel and device configuration. Fields: Connection *: TCP/IP (dropdown, inside a red box together with the IP field); IP *: empty; Port *: 502; Modbus unit ID *: 1 (inside a second red box). Buttons: Back (left), Test communication and Done (right).
Sungrow ESS C&I (ST battery series)
| Parameter | Value |
|---|---|
| Connection | TCP/IP |
| IP | IP address of the LC300. Click Scan for IP to find it. |
| Modbus ID | The Modbus ID from the LC300 web interface |
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Screenshot of the Reduxi Configurator wizard, step 2 Communication channel (step 1 is Basic settings). Heading: Communication channel and device configuration. Fields: Connection *: TCP/IP (dropdown); IP *: empty, with a dark button Scan for IP at its right end (the IP field and button are inside a red box); Port *: 502; Modbus unit ID *: 1 (inside a second red box). Buttons: Back (left), Test communication and Done (right).
6.3 Test communication
Click Test communication below the communication parameters. It checks whether the Modbus connection works. It reads the device once and saves nothing. If the test succeeds, click Done: only Done creates the device.
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Screenshot of the bottom of a Reduxi Configurator device form. Fields: Modbus unit ID *: 1; Rated power of inverter (kW) *: 10 (unit kW shown at the right). Buttons: Back (bottom left), Test communication and Done (bottom right). A red box highlights the Test communication button.
The test returns one of two results:
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Screenshot of a result dialog with green text: Successful readout from device. Lines: Active power: 0 W; Error: false null; Export active energy: 14227000 Wh; Max. active power: 0 W; Min. active power: -5000 W; PV current: 0.0 A; PV voltage: 362.25 V; Additional parameter - POWER_REACTIVE: 0. Button at the bottom right: Stäng [Swedish, Close].
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Screenshot of a dialog titled Test communication with a close x at the top right. Message in red text: Unable to communicate with device. Dark button at the bottom right: Close.
7 Check the readings
7.1 Last measurements
After communication is established, check the values under Devices – Sungrow – Last Measurements in the Reduxi Configurator as an additional test.
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Screenshot of the Reduxi Configurator device page, tab Last measurements (other tabs: Analysis, Archive, Details). Control type box with four buttons: Auto (selected, light blue, inside a red box), Manual, Off, Boost. Cards with value rows; the row labels are very small. Card Current: one value 17.26. Card Voltage: 229.33; 233.80; 235.80; 233.70. Card Power: -13.9; 13.9; 43.9; 0.0; 0.0; -44.0; 1.00. Card Energy: 34,321.3. Card Other: OFF; AUTO; 45.90. Each value has a small date and time stamp at the right.
7.2 Enable control by Reduxi
For advanced battery and inverter control, integrate the device into the Reduxi strategy. Under Devices – Sungrow in the Reduxi Configurator, set the control type to AUTO. Only then do strategy commands affect the inverter.
To achieve maximum flexibility and energy cost reduction with dynamic prices and dynamic tariffs, define a strategy as described in Strategies for Reduxi controller.
After you have added the device, you can also monitor and control it via the Reduxi application.
✓ Summary
Preparation (Points 1–2): Check the manufacturer manuals. Choose the connection method: WiNet-S/S2 or Data Logger for string and hybrid inverters, LC300 for ST batteries.
Sungrow (Points 3–4): Open Modbus TCP on port 502 and note the Modbus ID of the device. For the ST battery, set IP address, subnet mask and gateway on the LC300.
Add to Reduxi (Points 5–6): Log in to the Configurator, add the device, enter IP and Modbus ID, run Test communication and click Done.
Go live (Point 7): Check the last measurements and set the control type to AUTO.
→ Common issues
| Issue | Solution |
|---|---|
| Test communication fails with a WiNet-S/S2 or iSolarCloud connection | Modbus TCP is not open. Enable port 502 under System – Forwarding Configuration in the WiNet web interface, or set Modbus TCP 502 Port on/off to open in iSolarCloud (see Point 3). |
| Test communication fails although port 502 is open | Check the Modbus ID. Read the Forwarding Modbus ID under Device – Device List and enter the same value in the Reduxi Configurator. |
| The LC300 is not reachable | Check IP address, Subnet mask and Gateway under Parameter Settings – Comm Parameters (see Point 4). In the Configurator, click Scan for IP to find the LC300. |
| Strategy commands have no effect | Set the control type of the device to AUTO (see Point 7). For the ST battery, check that the local/remote setting of the LC300 is Local/Remote (see Point 4). |
| 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 here. |
reduxi.local does not load |
Your device is not in the same network as the controller. Use the IP address or the tunnel connection. |
| Communication test fails, device shows offline | Check reachability, IP address / port / unit ID, and that the protocol is enabled on the device. |