The portal connects but the power register reads zero at midday. Why?

The inverter may still have Modbus Function set to EV Charger instead of COM485. Re-enter Advanced Settings on the inverter LCD, confirm the Modbus Function is COM485, save, and restart the dongle. Zero readings during active generation almost always indicate this misconfiguration.

Connections drop randomly after a few minutes. What causes this?

The X3-MIC G2 and X3-PRO G2 accept only one Modbus TCP connection at a time. If another client (Home Assistant, evcc, a data logger) is also polling the dongle, sessions will collide. Ensure only the ModbusCloud Gateway is actively polling, or increase the polling interval to reduce contention.

The energy register value looks unexpectedly large or never resets. Is this normal?

Address 1087 holds a cumulative lifetime energy counter as a uint32. It does not reset daily. To calculate period yield, record start and end values and subtract. If the value appears to wrap around, the counter has exceeded the uint32 maximum; log both raw readings for accurate delta calculation.

I get a Modbus exception code 0x02 when reading these registers. What does it mean?

Exception code 0x02 means the register address is out of range or not supported by the connected firmware version. Confirm your inverter is an X3-MIC G2 or X3-PRO G2 (not a G1 or G4) and that the dongle firmware is at least Pocket WiFi 3.0, which is the minimum version that exposes these input registers via Modbus TCP.

Free Modbus template: Solax X3-PRO G2 (grid)

The Solax X3-PRO G2 is a three-phase, grid-tied string inverter for residential and commercial PV installations, covering the X3-MIC G2, X3-PRO G2, Q.VOLT P5T-X, and Q.VOLT P17T-X variants. This template communicates over Modbus TCP via the Solax Pocket WiFi or LAN dongle on port 502, reading instantaneous AC output power and cumulative energy yield from the inverter. Two registers give you a live production snapshot and a running energy total, enough to feed site-level reporting and EV-charging control logic in the ModbusCloud portal.

Name	Address	Function	Type	Unit	Access
power Instantaneous AC output power delivered to the grid, signed integer in watts.	1083	FC04	int32	W	R
energy Cumulative AC energy generated and fed to the grid, unsigned total count.	1087	FC04	uint32		R

Solax X3-PRO G2 (grid)

Overview

Use cases

Installation

Things to watch for

Registers (2)

Working with Modbus in your projects?

Free: RS485 and Modbus RTU installation checklist (PDF)

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