Huawei Sun + Luna2000 + DTSU666-H

Use cases

• Shift battery charging to low-tariff hours using dynamic pricing data and write setpoints through ModbusCloud automations.
• Track grid import and export separately for feed-in tariff reporting and net metering verification.
• Monitor battery state of charge and cell temperatures to catch cell imbalance or thermal issues early.
• Build a landlord dashboard showing PV yield, battery activity, and grid interaction per tenant installation.
• Enable or disable battery AC charging remotely when the installer needs to troubleshoot or run tests.

Installation

1. 1Confirm firmware versions: inverter V100R001C00SPC148 or newer, dongle SPC130 or newer, battery SPC116 or newer. Older firmware lacks the control registers.
2. 2Connect the SmartDongle WiFi/FE to the local network via LAN cable (WiFi also works but LAN is more stable for control use cases).
3. 3Enable Modbus TCP in the FusionSolar app under the dongle settings. On SPC148+ this is already on by default.
4. 4Add a Modbus TCP device in ModbusCloud at the dongle IP, port 502, slave ID 1, and import this template.
5. 5Increase the ModbusCloud query interval one step at a time if timeouts occur, starting at 5s and working up to 10s only if needed.

Things to watch for

01

Battery shows strange values like 6553.5% charge or 2.1 GW load. Is the template wrong?

No, this is a known Huawei standby-mode artefact. When the battery goes into deep sleep, the dongle briefly reports uninitialised register values that decode as these wild numbers. ModbusCloud filters out zero and negative outliers, but the battery itself has to recover. Values return to normal once the battery wakes.

02

Can I use this template alongside FusionSolar?

Yes but expect occasional read errors. The Huawei dongle only responds to one Modbus client at a time. If both ModbusCloud and FusionSolar poll the dongle, some requests will be rejected. Letting ModbusCloud be the only client gives the cleanest data.

03

I can read values but writing storage mode returns an error. What now?

Write access requires the inverter to accept external control, which is a one-time setup step in the FusionSolar app under Commissioning, Control mode. Some grid-managed installs have writes locked by the utility.

Registers (25)

22 read / 5 write

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