Installation · SolaX

Install GridZeno on SolaX X3-Fit.

X3-Fit G4 is SolaX's three-phase battery inverter. It has RS485 on pins 4 and 5 in the RJ45 port COM, which SolaX has set aside for data collection and external control with Modbus RTU. Pin 3 carries power, so the cable must be made with only the three wires that are needed.

Applies to: X3-Fit-6.0 to 15.0 G4.3 and G4.4 (W and M)
Connection: Network cable with RJ45 plug
Time: About 25 minutes

The battery is controlled with SolaX' remote control, which stops by itself if the dongle goes silent. What GridZeno can do on SolaX X3-Fit

How the dongle recognises it: The serial number starts with F34: X3-Fit/RetroFit G4.

GridZeno Dongle for SolaX X3-Fit

What you need

GridZeno Dongle: The device ID is on the label, e.g. GZ-A1B2C3.
Cable: A network cable that's re-crimped at the inverter end with only three wires.
RJ45 plug and crimping tool: For the inverter end.
USB power: A 5 V USB charger and a cable with USB-C.

The port

In the top row of communication ports on the underside, to the left of BMS and Meter/CT. Upgrade/Dongle and the cover over CAN1, CAN2, DRM and OFF are below. The cable is sealed by the port's coupling nut.

Port: COM

The COM port, with the pins numbered as SolaX numbers them. Pin 3 carries 13 V and must not be connected. The plug shown with the contacts facing you and the locking tab at the back: pin 1 is furthest to the left.

Pin 4 A, 485A
Pin 5 B, 485B
Pin 6 GND, GND
Pin 3 Must not be connected, +13V

The cable

A network cable where the inverter end is crimped with only three wires: the dongle's A on pin 4, B on pin 5 and GND on pin 6. The other positions in the connector are empty. An ordinary straight cable must never be used here: it would put the dongle's GND on pin 3, which carries power.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	SolaX pin 4, 485A
Dongle pin 5, white/blue (B)	SolaX pin 5, 485B
Dongle pin 3, white/green (GND)	SolaX pin 6, GND
The other wires	Cut off and insulated, especially the one on pin 3

Settings

On the inverter

Menu > Setting > Advance Setting > Modbus: Read off Baud Rate and Address. The dongle must have the same. The manual shows 19200 and 1.

In GridZeno's Welcome

The inverter is chosen in GridZeno: in Welcome the first time, and later under System, Change inverter. The dongle fetches its setup from there.

Manufacturer and model: SolaX, X3-Fit
Connection: By cable (RS485)
RS485 settings: The same baud rate and address as the inverter, 8N1. If the inverter is set to 19200, set 19200 on the dongle.

Step by step

Each step has a small drawing that shows what to do.

1
Read the baud rate and address
In the display, go to Menu, Setting, Advance Setting, Modbus. It requires the installer code. Note down Baud Rate and Address: the dongle must have the same.
2
Crimp the inverter end with three wires
Cut off the plug at the inverter end. Pass the cable through the COM port's coupling nut, and crimp a new plug on with blue (A) on pin 4, white/blue (B) on pin 5 and white/green (GND) on pin 6. The other wires are cut off and insulated.
3
Plug the connector into COM
The port is at the top left among the communication ports on the underside, before BMS and Meter/CT. Press the plug into the COM port until it clicks, and tighten the coupling nut so the port is sealed.
4
Plug the RJ45 end into the dongle
The cable's other end goes into the dongle's RS485 port. Place the dongle somewhere dry and close to the inverter, so the cable doesn't hang from the plug.
5
Connect power to the dongle
Plug the USB-C cable into the dongle and the charger into a socket. The dongle starts by itself. It gets power from the charger, not from the inverter.
6
Connect the dongle to the network
Over Wi-Fi: the first time, the dongle creates its own Wi-Fi, GridZeno-Setup- followed by the last characters of the device ID. Connect your phone to it, choose your own network, enter the password, and press Save and connect. When it says Connection OK, press Go to GridZeno. Over cable (LAN): plug a network cable from the router into the dongle's network port.
7
Log in, and choose your inverter
Log in to GridZeno. Welcome pairs the dongle with its device ID. Then choose your inverter, SolaX X3-Fit, and the connection By cable (RS485). Set the inverter's baud rate and address under RS485 settings. Press Save inverter, and the dongle fetches its setup and reads the inverter.

The dongle's own setup is described with screenshots in The user guide, and the pairing in Getting started.

Take care

Pin 3 in COM carries 13 V. An ordinary network cable connects all eight pins, so the inverter end must be crimped with only the three wires.

Use only COM. Meter/CT is the energy meter's port, BMS is the battery's, CAN1 and CAN2 are for other inverters, and OFF has +3.3 V on pin 6 and switches the inverter off if pins 4 and 6 are connected.

Pins 1, 2, 7 and 8 are dry contacts, for example for SolaX's Adapter Box and a heat pump. If there's already a cable in COM, write to us before you connect the dongle.

COM isn't a network port. Never plug it into a router or switch.

What GridZeno can control on SolaX X3-Fit, and how, is on the page about SolaX X3-Fit. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: SolaX X3-Fit G4 6 kW / 8 kW / 10 kW / 15 kW User Manual, version 9.0 (2026-04-08), Sections 2.5, Terminals of Inverter, 5.4.1, Introduction to COM Communication (COM PIN Definition), and Advance Setting, 8) Modbus.