Installation · Growatt

Install GridZeno on Growatt SPA.

SPA is built like SPH, with three RS485 ports with RJ45. The dongle goes in 485-1, and the RS485 setting in the display is set to VPP.

Applies to: SPA 4000-10000TL3 BH-UP
Connection: Network cable with RJ45 plug
Time: About 20 minutes

The battery is controlled with the inverter's own time windows, which the dongle saves and puts back afterwards. What GridZeno can do on Growatt SPA

How the dongle recognises it: The type code 3725, SPA TL3. The dongle reads it with its own map: the SPH map without solar inputs and with nothing in the 2000 range.

GridZeno Dongle for Growatt SPA

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 three wires.
RJ45 plug and crimping tool: For the inverter end.
Screwdriver: For the four screws in the waterproof cover.
USB power: A 5 V USB charger and a cable with USB-C.

The port

In the port panel on the underside between USB and GRID, behind the waterproof cover, together with 485-2, 485-3, CAN, DRMS, METER and NTC. The cable is passed in through the cover's cable gland. 485-2 can be used instead if 485-1 is taken.

Port: 485-1

The 485-1 port, with Growatt's pin numbering. A is on pin 5, B on pin 1 and GND on pin 2. The plug shown with the contacts facing you and the locking tab at the back: pin 1 is furthest to the left.

Pin 5 A, RS485A
Pin 1 B, RS485B
Pin 2 GND, GND

How it differs from SPH

SPA has no solar inputs. It charges a battery from the AC side of a solar system you already have, so the dongle reads no solar production from it.

SPH TL3 BH-UP has its own solar inputs. The type code is 3725 on SPA and 3601 on SPH, so the dongle tells them apart by itself.

The port, 485-1, and control with the inverter's own time windows are the same.

See the guide for SPH

The cable

A network cable where the inverter end is crimped with only three wires: the dongle's A (blue, pin 4) on pin 5, B (white/blue, pin 5) on pin 1 and GND (white/green, pin 3) on pin 2. The rest of the positions in the plug are empty. An ordinary straight cable doesn't work here, because SPA has A and B on pins 5 and 1, not on 4 and 5.

From the dongle to the inverter
Dongle end	Inverter end
Dongle pin 4, blue (A)	SPA pin 5, RS485A
Dongle pin 5, white/blue (B)	SPA pin 1, RS485B
Dongle pin 3, white/green (GND)	SPA pin 2, GND
The other wires	Cut off and insulated

Settings

On the inverter

RS485 Seting: VPP (from the factory it's set to unused)
Basic Parameter > RS485 Addr: COM Address 1, 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: Growatt, SPA
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
Set the RS485 setting to VPP
Hold Enter for more than 3 seconds to enter the setup, and choose RS485 Seting. Choose Port: VPP with Enter. From the factory it's set to unused. Shinemaster must not be chosen: then SPA goes into parallel operation. With VPP, SPA responds to the commands that come in on 485-1 and 485-2.
2
Remove the waterproof cover
The communication ports are on the underside between USB and GRID. If the waterproof cover is fitted over them, undo the four screws, and remove the cover.
3
Crimp the inverter end with three wires
Cut off the plug at the inverter end. Crimp a new RJ45 plug on with blue (A) on pin 5, white/blue (B) on pin 1 and white/green (GND) on pin 2. The other wires are cut off and insulated. The other end, for the dongle, keeps its plug.
4
Pass the cable through the cable gland
Unscrew the coupling nut from the cover's cable gland, and slide it onto the cable. Press out the sealing insert, take the filler plug out of one of the holes, put the cable in the hole, and pass it through the cable gland.
5
Plug the connector into 485-1
Press the plug into the 485-1 port, at the top right of the port panel above 485-2 and 485-3, until it clicks.
6
Close the cover again
Screw the waterproof cover on with the four screws, and screw the coupling nut onto the cable gland so the port is sealed.
7
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.
8
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.
9
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.
10
Log in, and choose your inverter
Log in to GridZeno. Welcome pairs the dongle with its device ID. Then choose your inverter, Growatt SPA, 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

Use 485-1 or 485-2. 485-3 is for Growatt's own service connection from a computer, METER for the energy meter and CAN for the battery.

If RS485 Seting is set to anything other than unused, the system already uses the port for something else, for example Meter2 or Shinemaster. In that case, write to us before you change it.

What GridZeno can control on Growatt SPA, and how, is on the page about Growatt SPA. If you're stuck, write to us with the model name.

Source

Ports, pins and menus are from the manufacturer's own manual: Growatt SPA 4-10KTL3 BH-UP User Manual (EN, 2025-12), Pin table on page 15, section 5.4.6, Connecting the RS485 terminal, 6.4.4, Setup, with RS485 Seting (diagram 6.12) and RS485 Addr (diagram 6.6), and 6.5.2, The 485-1/485-2 port.