Qcells Q.HOME ESS HYB-G3 (pv)

Installation

1. 1Enable Modbus RTU on the Q.HOME ESS HYB-G3 by navigating to Advanced Settings on the inverter display, then entering the Modbus section and confirming the baud rate (default 19200) and slave address (default 1).
2. 2Connect the ModbusCloud Gateway to the inverter RS485 COM port using an RJ45 cable: wire pin 4 (A+) and pin 5 (B-) of the RJ45 to the corresponding A and B terminals on the Gateway's RS485 interface.
3. 3In the ModbusCloud portal, add a new device, select the Qcells Q.HOME ESS HYB-G3 (pv) template, and assign the unit ID matching the slave address configured on the inverter (typically 1).
4. 4Verify the connection by checking the live readings for power_a and power_b during daylight: both registers should return non-zero watt values when PV strings are producing.

Things to watch for

01

Why do power_a and power_b always read zero, even in sunshine?

Confirm the inverter is in on-grid or self-use mode and that PV strings are active. Also verify the baud rate on both the inverter display and the Gateway match exactly. A mismatch, even one step off (for example 9600 vs 19200), will produce silent failures where the Gateway connects but returns no valid data.

02

The Gateway shows a connection but all three registers return errors. What is wrong?

Check that the RS485 A and B wires are not swapped. On the RJ45 COM port, pin 4 is A+ (positive) and pin 5 is B- (negative). Reversed polarity causes framing errors on the Modbus RTU bus without breaking the physical link, so the connection appears alive but all reads fail.

03

The energy register rolls back to zero unexpectedly. Is this normal?

The energy register is a uint32 cumulative counter. At very high lifetime totals the counter can overflow and restart from zero. Cross-check the portal's historical trend to distinguish a genuine overflow from a communication dropout that caused a missed reading, which can also appear as a reset.

04

Two inverters are on the same RS485 bus and readings are unreliable. How do I fix this?

Each device on a shared RS485 bus must have a unique Modbus slave address. On the Q.HOME ESS HYB-G3, change the address in Advanced Settings on the inverter display. Assign one unit a unique ID, then update the corresponding ModbusCloud device entry to match. Ensure only one master (the Gateway) polls the bus.

Registers (3)

3 read / 0 write

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