Why does the power register always read zero or a fixed value?

The most common cause is a baud rate mismatch. The Solax inverter defaults to 19200 baud, but many RS485 adapters default to 9600. Check the inverter display under Settings, Advanced Settings, Modbus, Baud Rate and set the adapter to match. Also confirm the slave ID matches on both sides.

Grid power shows a value, but voltages and currents are all zero. Why?

Addresses 202 to 208 are input registers in a different block from address 70. Some RS485 adapters impose a query interval limit. Ensure your polling interval is at least 1 second between consecutive requests, as the Solax protocol requires a minimum gap of 1 second between Modbus commands.

The gateway connects but data disappears after a few minutes. What is happening?

Solax inverters support only a single Modbus master at a time. If another device (such as a home automation system or a Wi-Fi dongle also polling via Modbus TCP) is connected simultaneously, the inverter will block or drop one connection. Disconnect any other Modbus master or use a TCP multiplexer.

Can I connect the COM port on the G4 inverter directly to a network switch?

No. The COM port on the G4 inverter uses an RJ45 connector but carries RS485 signals, not Ethernet. Connecting it directly to an Ethernet switch will damage the switch port. Always use a dedicated RS485-to-Ethernet adapter between the inverter and your LAN.

Free Modbus template: Solax Hybrid X1/X3 G3/G4 (grid)

The Solax Hybrid X1/X3 G3/G4 is a single- and three-phase hybrid solar inverter with integrated battery management, deployed in residential and small-commercial PV storage systems. This template connects via Modbus TCP through an RS485-to-Ethernet bridge and reads the grid-side registers of the Hybrid X1/X3 G3/G4: instantaneous grid power flow (signed, covering both import and export), cumulative grid energy, and per-phase voltages and currents across all three phases. It gives installers and asset managers a complete picture of grid interaction without requiring cloud access.

Name	Address	Function	Type	Unit	Access
power Grid power flow, signed: positive means export, negative means import.	70	FC04	int32	W	R
energy Cumulative grid energy, total lifetime value as unsigned integer.	74	FC04	uint32	Wh	R
currents_a Grid current on phase A, signed 16-bit value.	206	FC04	int16	A	R
currents_b Grid current on phase B, signed 16-bit value.	207	FC04	int16	A	R
currents_c Grid current on phase C, signed 16-bit value.	208	FC04	int16	A	R
voltages_a Grid voltage on phase A, unsigned 16-bit value.	202	FC04	uint16	V	R
voltages_b Grid voltage on phase B, unsigned 16-bit value.	203	FC04	uint16	V	R
voltages_c Grid voltage on phase C, unsigned 16-bit value.	204	FC04	uint16	V	R

Solax Hybrid X1/X3 G3/G4 (grid)

Overview

Use cases

Installation

Things to watch for

Registers (8)

Working with Modbus in your projects?

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