Growatt Modbus RTU (RS-485)
This guide describes step by step how to connect a Growatt inverter to the Currentt Navigator via Modbus RTU over the RS485 port (COM connector).
✅ Compatible models
Single-phase inverters
| Model | Power |
|---|---|
| MIN 2500–6000TL-XH | 2.5 – 6 kW |
Three-phase inverters
| Model | Power |
|---|---|
| MOD 3000–15000TL3-XH | 3 – 15 kW |
Single-phase hybrid inverters
| Model | Power |
|---|---|
| SPH 3000–10000TL-BL-EU | 3 – 10 kW |
Three-phase hybrid inverters
| Model | Power |
|---|---|
| SPA 4000–10000TL-BL-EU | 4 – 10 kW |
🧰 Requirements
- Currentt Navigator Pro (with RS-485 Modbus connection)
- RS-485 cable (twisted pair, e.g. CAT5 or a suitable 2-wire cable)
- Phillips screwdriver (for access to the communication port)
⚠️ Safety warnings
Always switch off the inverter before making the communication connection. Set the DC switch to OFF and switch off the AC side via the distribution board.
🪛 Installation instructions
Step 1: Switch off the inverter
- Set the DC switch on the inverter to OFF
- Switch off the AC side via the distribution board (circuit breaker)
- Wait at least 5 minutes for the capacitors to discharge
- Check that the inverter display is off
Step 2: Connect the RS-485 cable
The RS-485 port is located on the bottom of the Growatt inverter, near the communication ports.
- Remove the cover from the COM port on the bottom of the inverter
- Connect the RS-485 cable to the RS-485 terminals on the inverter:
| Terminal | Signal | Description |
|---|---|---|
| RS485-A | Data+ | Non-inverting (positive) |
| RS485-B | Data− | Inverting (negative) |
- Connect the other end to the RS-485 Modbus connection on the Currentt Navigator (A to A, B to B)
- Use a twisted pair cable for a reliable connection
- Replace the cover
Ensure that the A and B connections are wired correctly. Swapping A and B will cause communication errors.
Connect the ground (GND) on one side only: either to the Currentt Navigator or to the device — but never on both sides. Connecting ground on both sides can cause a ground loop, leading to communication errors.
Step 3: Switch on the inverter
- Switch on the AC side via the distribution board
- Set the DC switch on the inverter to ON
- Wait for the inverter display to start up
Step 4: Configure the inverter
The communication settings are configured via the LCD display on the inverter.
- Press and hold the OK/Enter button until the menu opens
- Navigate to the settings/parameter menu and use the default password 123 to log in
- Set the following values:
| Setting | Value |
|---|---|
| COM/Modbus address | 1 (leave at 1 for a single inverter; adjust for multiple inverters so each inverter has a unique address) |
| Baud rate | 9600 |
| Frame | 8 data bits, no parity, 1 stop bit (9600-8-N-1) (this is the Growatt default and usually not configurable) |
| Protocol | Modbus RTU |
Additional setting for SPH/SPA models:
| Setting | Value |
|---|---|
| RS485 mode | VPP (otherwise the inverter will not accept external control) |
- Confirm the settings
When using multiple Growatt inverters on the same RS-485 bus, each inverter must have a unique COM/Modbus address (e.g. 1, 2, 3). Set this via the display on each inverter.
Step 5: Configuration in the Currentt Navigator
After connecting the RS-485 cable and configuring the inverter, the device must be added in the Currentt Navigator.
Via the Setup Wizard (recommended)
- Click the settings icon (top right of the screen)
- Choose Setup Wizard
- Follow the on-screen steps
Manual configuration
- Click the settings icon (top right of the screen)
- Go to Components
- Click the + button in the Inverters section
- Select Growatt
- Enter the connection details:
| Parameter | Value |
|---|---|
| Connection | Modbus RTU (RS-485) |
| Modbus address | 1 (default) |
| Baud rate | 9600 |
| Data bits | 8 |
| Parity | None (N / disabled) |
🔗 Multiple inverters (daisy-chain)
When using multiple Growatt inverters on the same RS-485 bus:
- Connect the inverters to each other via RS-485 (daisy-chain)
- Connect the first inverter to the Currentt Navigator
- Give each inverter a unique Modbus address (1, 2, 3, etc.)
- Place a 120Ω termination resistor at the end of the RS-485 bus (on the last inverter in the chain)
📋 Settings summary
| Parameter | Value |
|---|---|
| Connection | RS-485 (Modbus RTU) |
| Protocol | Modbus RTU |
| Modbus address | 1 (default) |
| Baud rate | 9600 |
| Data bits | 8 |
| Parity | None (N / disabled) |
🛟 Troubleshooting
| Problem | Possible cause | Solution |
|---|---|---|
| No connection | A and B swapped | Check the polarity of the RS-485 connection |
| No connection | Wrong Modbus address | Check the Modbus address on the inverter display |
| No connection | Wrong baud rate | Check that the baud rate matches (default 9600) |
| No connection | Wrong protocol | Check that the protocol is set to Modbus RTU (not the Growatt proprietary protocol) |
| No connection | Cable too long or damaged | Use a shorter cable or check for damage |
| Unreliable communication | No termination | Place a 120Ω termination resistor at the end of the RS-485 bus |
| No communication | Inverter in sleep mode | The inverter may not communicate when there is no PV production (depending on model and firmware) |
| Read-only, no control | External EMS not enabled | Enable the External EMS mode via the inverter display |