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.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 2, read only
- Brand
- Solax
- Compatible models
- X3-MIC G2 · X3-PRO G2 · Q.VOLT P5T-X · Q.VOLT P17T-X
- Last updated
Registers (2)
2 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read | |||
| energy | Read |
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Use cases
- Monitor real-time AC output power to verify the inverter is producing at expected levels during peak sun hours.
- Track cumulative energy yield over time to report monthly PV generation to building owners or grid operators.
- Alert on a sudden drop in power register values to detect inverter faults or grid disconnection events quickly.
- Compare daily energy totals across multiple X3-PRO G2 units on a multi-string commercial rooftop installation.
- Feed live power data into an EV-charging controller to align wallbox charging with available solar surplus.
Installation
Enable Modbus communication on the inverter: navigate to Advanced Settings, then Modbus, set the Modbus Function to COM485, note the RS485 address (default 1), and confirm the baud rate setting.
Connect the Solax Pocket WiFi 3.0 or LAN dongle to the inverter's dongle port and attach it to the same LAN as the ModbusCloud Gateway; the dongle exposes Modbus TCP on port 502.
In the ModbusCloud portal, add the Gateway, import the Solax X3-PRO G2 (grid) template, and set the unit ID to match the inverter's RS485 address configured in step 1.
Verify the connection by checking the live value of the power register (address 1083) in the portal; a non-zero reading during daylight confirms successful communication.
Things to watch for
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.
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