SolaX X3-Fit with GridZeno.

SolaX X3-Fit on the compatibility list, updated 31 October 2026.

• Live overview of solar, consumption and gridAll subscriptions · Solar and consumption require a meter on the solar inverter you already have.
  Works
• Battery state of chargeAll subscriptions · requires a battery
  Works
• Stop selling at negative pricesSmart and Pro · Requires the installer to have turned export limiting on in the inverter. GridZeno only lowers a limit that's already set.
  Works
• Charge from the grid when power is cheapSmart and Pro · requires a battery
  Works
• Discharge the battery when power is expensivePro · requires a battery
  Works

Works: tested and measured on real hardware.

The dongle controls the battery with SolaX' remote control.

Charge, hold and sell

A command with the battery's power and a duration. When the duration is over, the inverter stops by itself, so the battery never gets stuck in a command if the dongle goes silent.

Stop selling at negative prices

The inverter's export limit is set quarter by quarter by the selling price, but only where the installer has turned export limiting on. GridZeno only lowers a limit that's already set and never turns it on or off.

Battery limits

Your lowest state of charge is written to the inverter's own limit.

Locked inverter

GridZeno never unlocks the inverter. If it's locked, you unlock it in the SolaX app or in the menu. It locks itself again after a restart.

Solar and consumption

Requires a meter on the solar inverter you already have. The grid is always shown.

Manual

When the control is on Manual, the dongle changes nothing on the inverter. It reads, and if GridZeno has changed something, it puts the inverter's own settings back, including your own charge limits.

The serial number starts with F34: X3-Fit/RetroFit G4.

Solar and consumption

The X3-Fit has no solar input. Solar and consumption come from meter 2 (input 0xA8) while 0xB9 = 1. Without meter 2 they aren't shown.

The export limit

In 10 W. The inverter's AC power is the sum of the three phases.

How it differs from its neighbours

• SolaX X1-Fit: The single-phase X1-Fit is controlled the same way, but the export limit is in 1 W.

For the installer: the registers

What the dongle uses over Modbus, if you want to follow along or troubleshoot. Don't change the registers yourself while control is set to Automatic.

Control

One block of 8 registers from 0xA0 with function 0x10: mode 8, the battery power and a duration of 60 seconds to 8 hours. Released with 13 zeros from 0x7C.

Export limit

Written in 0x42 and read in 0xB6. The installer's value is saved and written back exactly as it was.

Lowest charge level

By the work mode in 0x8B: Self Use in 0x61, Feed-in Priority in 0x65, Backup in 0x67.

Rated power and firmware

The rated power in 0xBA, the Modbus protocol in 0x82.

From the dongle's firmware and our notes on each inverter, not from the datasheet.

Network cable with RJ45 plug. Approx. 25 minutes.

Port

COM

Pin

A at pin 4 (485A), B at pin 5 (485B), GND at pin 6 (GND)

Where

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.

See the full installation guide for SolaX X3-Fit

GridZeno Dongle for SolaX X3-Fit

This one works.

SolaX X3-Fit is the inverter GridZeno has been tested on. Check that your model is under X3-Fit-6.0 to 15.0 G4.3 and G4.4 (W and M), and that a battery is fitted if you want the battery controlled by the electricity price. If it still doesn't suit you, you have 100 days' free return.