Installation · Sofar Solar

Install GridZeno on Sofar ESI-T1.

ESI-T1 is Sofar's three-phase hybrid inverter, stacked with BTS batteries. The communication ports are gathered behind one COM housing: six RJ45 ports and a terminal block. Sofar's RS485 for monitoring is pins 1 and 2 in the Link0 port, which is also used for inverters in parallel. The cable is made with only the two wires that are used.

Applies to: ESI-5K to ESI-12K-T1
Connection: Network cable with RJ45 plug
Time: About 25 minutes

What GridZeno can do on Sofar ESI-T1 today

There's no public register map for the ESI 5-12K-T1, 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 ESI-T1

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 side of the inverter, behind the COM housing's cable gland. The ports are in three rows: Wall Box and Ethernet, Meter/CT and DRMs, Link0 and Link1. Below them is the Dry & Wet Contact terminal block.

Port: Link0 in the COM housing

The Link0 port, as Sofar numbers the pins. Pins 1 and 2 are RS485 for monitoring, pins 4 to 8 are parallel operation. 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, RS485 A
Pin 2 B, RS485 B

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 A
Dongle pin 5, white/blue (B)	Sofar pin 2, RS485 B
The other wires	Cut off and insulated

Settings

On the inverter

System Settings > 6. RS485 Communication: Modbus address 01 and baud rate 9600, as from the factory.

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, ESI-T1
Connection: By cable (RS485)
RS485 settings: Keep the default: 9600 baud, 8N1, address 1.

Step by step

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

1
Check address and baud rate
On the display, go to System Settings and 6. RS485 Communication. The address must be 01 and the baud rate 9600, as from the factory.
2
Pass the cable through the COM housing
Switch off the inverter first: choose Advanced Settings, Switch On/Off, Switch Off, switch off the grid and load breakers, set the PV switch to OFF, switch off the battery, and wait 5 minutes. Remove the rubber plug from the hole in the COM housing's seal that you're going to use, and pass the cable through the cable gland, the clip and the hole.
3
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.
4
Insert the plug in Link0
Push the plug into the Link0 port until it clicks, and lock the COM housing back on. If the inverter is in parallel with others, use the Link port that's free.
5
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.
6
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.
7
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.
8
Log in, and choose your inverter
Log in to GridZeno. Welcome pairs the dongle with its device ID. Then choose your inverter, Sofar Solar ESI-T1, 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

Link0 and Link1 are also used when several inverters are in parallel. If there are already cables in both, write to us before you connect the dongle.

DRMs has DRM0 on pin 6, and the E-STOP terminals in Dry & Wet Contact stop the inverter. Never plug the dongle's cable into them. Meter/CT is the energy meter's port and Wall Box the charger's.

The Ethernet port isn't in use yet, Sofar writes. The dongle doesn't go in it.

Sofar ESI-T1 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 ESI 5-12K-T1 User Manual V1.9 (EN, 2026-02), Section 5.6, Communication connection (figure 5-25, the Link0/Link1 table), and System Settings, 6. RS485 Communication.