Installation · Growatt

Install GridZeno on Growatt WIT.

WIT has seven RJ45 ports gathered behind a cable gland. The dongle goes in the RS485-IN port, where pins 7 and 8 are Growatt's own connection for external control (EMS/VPP). The inverter doesn't need any 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 4-15K-HU
Connection: Network cable with RJ45 plug
Time: About 20 minutes

Tested on our own system: a WIT 15K-HU with a 16 kWh battery. What GridZeno can do on Growatt WIT

How the dongle recognises it: The type code 5603 in holding 30000 and a rated power in 30016 of at most 15 kW. If holding 988 reads 1, it's a WIS, which the dongle never controls as a WIT.

GridZeno Dongle for Growatt WIT

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 fed through the gland.
USB power: A 5 V USB charger and a cable with USB-C.

The port

In the COM1 communication area together with the other RJ45 ports. The cables are fed in through the cable gland (the PG head). RS485-OUT (CN3) has the same pins and can be used if RS485-IN is taken.

Port: RS485-IN (CN2)

The RS485-IN port, as Growatt numbers the pins. RS485_3 is the connection for external control. 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 cable 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

Settings on the inverter: None. WIT answers on Modbus address 1 at 9600 baud, which the dongle uses 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: Growatt, WIT
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
Open the inverter
Switch off the inverter on AC and DC, as Growatt's manual describes. Unscrew the six screws in the bottom cover with a Torx screwdriver, and take the cover off. Behind it are the communication ports and the connections to grid, load and battery.
2
Feed the cable up through the gland
Unscrew the PG head on the underside, take a rubber plug out of one of the holes, and feed the cable up through it to the communication ports. 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 RS485-IN (CN2) until it clicks. Tighten the PG head, and screw the cover back on with the six screws.
5
Plug the other end into the dongle
The 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. BMS1 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, and how, is on the page about Growatt WIT. 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 4-15K-HU User Manual (EN, 2025-11), Section 6.6.1, COM1/COM2 Connection, and table 6.5.