Installation · Sofar Solar

Install GridZeno on Sofar KTLX-G4-ESS.

KTLX-G4-ESS is Sofar's large three-phase inverter with solar panels and battery on the same DC side, for business and farming. The COM plug has six RJ45 ports. The monitoring RS485 is on pins 1 and 2 in RJ45_5 and RJ45_6, which are identical, so the cable can be passed on. There's no GND, so the cable is made with only two wires.

Applies to: 80K, 99K, 100K, 110K and 125KTLX-G4-ESS
Connection: Network cable with RJ45 plug
Time: About 30 minutes

What GridZeno can do on Sofar KTLX-G4-ESS today

There's no public register map for the KTLX-G4-ESS, so the dongle can't read it yet.

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You can connect the dongle by this guide, but it reads nothing from the inverter until its firmware can. GridZeno Dongle for Sofar KTLX-G4-ESS

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 two 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

On the underside of the inverter, between USB/Wi-Fi and AC. COM is a single waterproof shared plug with six RJ45 ports, RJ45_1 to RJ45_6, and an 8-pole terminal.

Port: RJ45_5 in the COM plug

The port RJ45_5 (and RJ45_6), as Sofar numbers the pins. Pins 1 and 2 are the monitoring RS485, pins 4 and 5 the energy meter's. The plug shown with the contacts facing you and the locking tab at the back: pin 1 is furthest to the left.

Pin 1 A, Monitor RS485_1A
Pin 2 B, Monitor RS485_1B

The cable

A network cable where the inverter end is crimped with only two wires: the dongle's A on pin 1 and B on pin 2. The rest of the positions in the plug are empty. An ordinary straight cable doesn't work here.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	Sofar pin 1, RS485_1A
Dongle pin 5, white/blue (B)	Sofar pin 2, RS485_1B
The other wires	Cut off and insulated

Settings

On the inverter

The Modbus address: The manual doesn't show where the address and baud rate are set. Write to us, and we'll find them in Sofar's protocol.

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: Sofar Solar, KTLX-G4-ESS
Connection: By cable (RS485)
RS485 settings: Start with 9600 baud, 8N1 and address 1.

Step by step

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

1
Pass the cable through the COM plug
Turn off the inverter first: switch off the AC breaker, set the DC switch to OFF, and wait 5 minutes. Take the COM plug apart, and pass the cable through its parts before the connector is crimped on.
2
Crimp the inverter end with two wires
Cut off the plug at the inverter end. Crimp a new plug on with blue (A) on pin 1 and white/blue (B) on pin 2. The other wires are cut off and insulated.
3
Plug the connector into RJ45_5
Push the connector into RJ45_5 until it clicks. If the energy meter's cable is already in RJ45_5, use RJ45_6. Assemble the COM plug, and plug it into the inverter.
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, Sofar Solar KTLX-G4-ESS, and the connection By cable (RS485). 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

RJ45_1 is DRM, where pin 6 can stop the inverter, RJ45_2 is Ethernet, RJ45_3 inputs and outputs and RJ45_4 the battery. Never plug the dongle's cable into them. Terminal A-5 in the same plug carries power.

If the inverter runs in parallel with Sofar's CH1000 box, that box is already master on RS485. Write to us before you connect the dongle.

The inverter is large and heavy and sits on a high-voltage system. The work should be done by a qualified person, such as an authorised electrician.

Sofar KTLX-G4-ESS isn't on the compatibility list yet. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: SOFAR 80-125KTLX-G4-ESS User Manual V1.1 (EN, 2026-08), The section on the COM port (figure and pin table for RJ45_1 to RJ45_6 and A-1 to A-8) and fitting the COM plug.