How to connect Bluesun BSC-125kW battery (BESS) with Reduxi controller
Connect a Bluesun BSC-125KW-261KWH battery energy storage system to the Reduxi Controller.
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Product photo of a white outdoor battery energy storage cabinet on a light background. The cabinet is tall with a rounded white side panel, three round indicator lights near the top (yellow, green, red) with small text beneath them, and a small logo at the upper left. A grey ventilation grille and a door with a handle are on the lower front, and 'BLUE SUN' is printed at the lower right of the front. An orange label on the left reads '125kW 261kWh' and, in a smaller bar below it, 'Liquid-Cooled'.
1 Technical documentation
The Bluesun BSC-125KW-261KWH is a liquid-cooled battery energy storage system (BESS) for commercial and industrial use. The data below comes from the Bluesun datasheet.
Manufacturer documents:
- Bluesun Liquid Cooling Storage System 125KW/261KWH – datasheet (PDF, EN)
- 125kW 261kWh Liquid-Cooled Energy Storage System – product page (web, EN)
2 Required equipment
- Reduxi Controller (installed and online)
- Bluesun BSC-125KW-261KWH, commissioned
- Connection between the system and the Reduxi Controller (see Point 3)
- Modbus register map of the system from Bluesun
- Laptop or tablet with internet access to configure the device in Reduxi
3 System overview and wiring
A battery energy storage system must support Modbus communication with a complete register map for monitoring and control. The requirements are in Integration requirements for battery energy storage system (BESS).
Per the datasheet, each rack contains the battery modules and a 125 kW inverter. The system uses CAN for battery communication. Remote data access runs over Wi‑Fi, 4G, 5G or LAN through the Bluesun ESS Cloud. The EMS offers peak shaving, self-consumption and UPS modes.
4 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.
5 Add the device to Reduxi
Open the Configurator first, see Point 4. The device is added with the wizard in two steps.
5.1 Basic settings
Bluesun BSC-125kW. Tick the strategies the device should take part in, then click Next.5.2 Communication settings
The second step sets up the Modbus communication between the Reduxi Controller and the system. Enter the connection type, the address and the Modbus unit ID as they are set on the system.
5.3 Test communication
Click Test communication at the bottom of the wizard. It reads the Bluesun BSC-125kW once and saves nothing. If the test succeeds, 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.
6 Check the readings
6.1 Last measurements
Open Devices → your Bluesun device → Last measurements in the Configurator. The values show whether the system communicates correctly.
6.2 Control behaviour
For control by the Reduxi strategies, open Devices and your Bluesun device in the Reduxi Configurator and set the control type to AUTO. Only then do strategy commands affect the battery.
To reduce energy costs with dynamic prices and tariffs, define the strategy as described in Strategies for Reduxi controller.
✓ Summary
Preparation (Points 1–2): Check the datasheet. Get the Modbus register map from Bluesun and prepare the equipment.
Bluesun BSC-125KW-261KWH (Point 3): Connect the system to the Reduxi Controller. The system must support Modbus.
Add to Reduxi (Points 4–5): Open the Configurator, add the device, enter the communication settings, run Test communication and click Done.
Go live (Point 6): Check the last measurements and set the control type to AUTO.
→ Common issues
| Issue | Solution |
|---|---|
| Test communication fails | Check the connection type, address and Modbus unit ID against the settings on the system. Controller and system must be able to reach each other. |
| The type of the Bluesun system is not selectable | Only types listed in the List of supported devices can be selected. The system must support Modbus (see Integration requirements for BESS). |
| 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. |