Installation · Growatt

Install GridZeno on Growatt WIT 17-25K-HU and 4-25K-XHU.

The WIT 17-25K-HU and WIT 4-25K-XHU hang on the wall and have the same seven RJ45 ports behind the lower cover. The 17-25K-HU measures about 475 × 695 × 241 mm, the 4-25K-XHU about 465 × 687 × 241 mm. The dongle goes in the RS485-IN port, where pins 7 and 8 are Growatt's connection for an external controller (EMS/VPP). The inverter needs no settings.

Needs an electrician: the inverter has to be opened

The inverter has to be opened to get to the communication ports, and behind the cover are also the connections to grid, load and battery. This should be done by a qualified person, e.g. an authorised installer.

Applies to: WIT 17K, 18K, 20K, 22K and 25K-HU and WIT 4K to 25K-XHU (all ten sizes)
Connection: Network cable with RJ45 plug
Time: About 20 minutes

Controlled like the Growatt WIT: charging and holding with the inverter's operating mode, selling with Growatt's VPP protocol. The dongle always sets the inverter's own mode back afterwards. What GridZeno can do on Growatt WIT 17-25K-HU and 4-25K-XHU

How the dongle recognises it: Neither the WIT 17-25K-HU nor the WIT 4-25K-XHU has a type code of its own in any table. The dongle sees 5603 and tells them apart by the rated power in 30016: above 15 kW it's a WIT above 15 kW.

GridZeno Dongle for Growatt WIT 17-25K-HU and 4-25K-XHU

What you need

GridZeno Dongle: The device ID is on the label, e.g. GZ-A1B2C3.
Cable: Cat5e cable, 1.5 m or the length you need.
RJ45 plug and crimping tool: For the inverter end, which is crimped after the cable has been passed through the PG gland.
Allen key: For the six screws in the lower cover. It comes with the inverter.
USB power: A 5 V USB charger and a cable with USB-C.

The port

On the COM1 communication board behind the lower cover: CN1/BMS-1, CN2/RS485-IN and CN3/RS485-OUT at the top, CN4/METER, CN5/DI, CN6/PARA_IN and CN7/PARA_OUT at the bottom. The cables are passed in through the PG gland at COM1 on the underside. RS485-OUT (CN3) has the same pins.

Port: RS485-IN (CN2)

The RS485-IN port, with Growatt's pin numbering. RS485_3 on pins 7 and 8 is for EMS/VPP. The plug shown with the contacts facing you and the locking tab at the back: pin 1 is furthest to the left.

Pin 8 A, RS485_3A
Pin 7 B, RS485_3B
Pin 2 GND, GND.S

The cable

A network cable where the inverter end is crimped with only three wires: the dongle's A on pin 8, B on pin 7 and GND on pin 2. The rest of the positions in the plug are empty. An ordinary straight cable doesn't work here, because the GridZeno dongle has A and B on pins 4 and 5, and Growatt on pins 8 and 7. The cable has to go through the PG gland before the plug goes on at the inverter end, so that end is crimped on site with an RJ45 crimping tool.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	Growatt pin 8, RS485A
Dongle pin 5, white/blue (B)	Growatt pin 7, RS485B
Dongle pin 3, white/green (GND)	Growatt pin 2, GND
The other wires	Cut off and insulated

Settings

On the inverter

ShineTools > Basic Settings: COM Address 1 and Baud Rate 9600bps, as from the factory. The dongle uses the same.

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: Growatt, WIT for 4-15 kW and WIT over 15 kW for 17-25 kW
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
Switch off the inverter, and remove the lower cover
Turn off the AC breaker, set the DC switches to OFF, and disconnect the battery. Wait 5 minutes. Undo the six screws in the lower cover with the Allen key, and remove the cover.
2
Pass the cable up through the PG gland
Unscrew the PG gland at COM1 on the underside, take a rubber plug out of one of the holes, and pass the cable up through it. Leave the plugs in the holes you don't use, so no water gets in.
3
Terminate the cable with an RJ45 plug
Strip 14 to 16 mm, and crimp the RJ45 plug on with blue (A) on pin 8, white/blue (B) on pin 7 and white/green (GND) on pin 2. The other wires are cut off and insulated.
4
Plug the connector into RS485-IN
Press the plug into the port marked CN2/RS485-IN until it clicks. Tighten the PG gland, and screw the cover back on with the six screws so it seals tightly.
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, Growatt WIT, 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

Only use RS485-IN or RS485-OUT. BMS-1 is the battery's connection and METER the energy meter's.

Growatt requires the electrical installation, that's power, solar and battery, to be done by an authorised electrician. The communication cable is low voltage.

What GridZeno can control on Growatt WIT 17-25K-HU and 4-25K-XHU, and how, is on the page about Growatt WIT 17-25K-HU and 4-25K-XHU. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: Growatt WIT 17-25K-HU User Manual (EN, 2026-06) and WIT 4-25K-XHU User Manual (EN), Section 3.1, Overview, 6.6.1, Communication network port, with figures 6.15-6.17 and table 6.5, and 8.1.2, Basic Settings.