Huawei SUN2000 Hybrid Inverter (battery)
The Huawei SUN2000 Hybrid Inverter is a residential and light-commercial solar inverter with integrated battery management, designed to pair with LUNA2000 battery storage. This Modbus TCP template targets the battery control layer of the SUN2000, exposing write registers for forcible charge and discharge commands, charge power and discharge power setpoints, charge-from-grid enable, forcible mode selection, and time-of-use schedule configuration. With the ModbusCloud Gateway connected via the Smart Dongle, you can automate battery dispatch from your portal to match grid tariffs or site demand, without relying on the FusionSolar app.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 6, read and write
- Brand
- Huawei
- Last updated
Registers (6)
0 read, 6 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| batterymode_a | Write | ||||
| batterymode_c | Write | ||||
| batterymode_d | Write | ||||
| batterymode_e | W | Write | |||
| batterymode_i | W | Write | |||
| batterymode_j | Write |
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Use cases
- Trigger forcible grid charging via the batterymode_a register during low overnight tariff windows.
- Set discharge power limits through batterymode_e to prevent peak grid draw during high-demand periods.
- Enable or disable charge-from-grid using batterymode_d to comply with grid operator export rules.
- Switch between duration mode and TOU schedule via batterymode_c to align battery behaviour with dynamic pricing.
- Verify that forcible charge power written to batterymode_i does not exceed the rated capacity of the installed battery packs.
Installation
Enable Modbus TCP on the SUN2000 through the inverter's internal settings menu under the communication or Modbus section, and confirm the Smart Dongle firmware is up to date.
Connect the Smart Dongle to your local network and note its IP address. Ensure the ModbusCloud Gateway is on the same LAN segment and can reach port 502 (or 6607 on newer firmware) of the dongle.
In the ModbusCloud portal, add a new device, import the Huawei SUN2000 Hybrid Inverter (battery) template, and set the Modbus unit ID to match the inverter's configured slave address (default 1).
Write the value 0 to batterymode_a (Stop) from the portal's register console and confirm the inverter acknowledges the command with no fault, verifying the write path is fully operational before using active setpoints.
Things to watch for
Why does writing to batterymode_a return no error but the battery ignores the command?
The forcible charge or discharge command at address 47100 only takes effect when charge-from-grid (batterymode_d, address 47087) is set to 1 (enabled). Write that enable register first. Additionally, the forcible mode setting (batterymode_c, address 47246) must be written to 0 for duration-based control before issuing the command.
The gateway connects but all write operations time out. What is wrong?
The SUN2000 Modbus TCP interface is known to require response timeouts of at least 800 ms to 2000 ms. Set a longer timeout in the ModbusCloud Gateway configuration. Also confirm the port is correct: older inverter firmware uses port 502, while newer firmware versions use port 6607.
Modbus TCP becomes unstable when FusionSolar cloud monitoring is active. How do I fix this?
Modbus TCP via the Smart Dongle can coexist with FusionSolar, but unstable behaviour is common when other clients poll the dongle simultaneously. Reduce polling frequency in the portal and ensure only one Modbus master is active at a time. For RS-485, disconnect the WLAN dongle entirely to avoid conflicts.
Is it safe to write arbitrary watt values to batterymode_i and batterymode_e?
No. Writing a charge or discharge power setpoint higher than the battery pack's rated power can trigger protection faults and may affect warranty. For a single LUNA2000 pack the rated charge and discharge power is limited. Always verify the maximum rated power in your system documentation before writing to these registers, and start with conservative values.
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