Device Growatt Spf Modbus Register 81: Name inverter name mppt charger fan speed

Technical Definition

The register name inverter name mppt charger fan speed at address 81 is used to monitor name inverter name mppt charger fan speed on the Device Growatt Spf.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: %
• Access: Read Only

How to Read (Python pymodbus)

Use this code snippet to read this specific value via RS485:

from pymodbus.client.sync import ModbusSerialClient

client = ModbusSerialClient(method='rtu', port='/dev/ttyUSB0', baudrate=9600)
client.connect()

# Read name_inverter_name_mppt_charger_fan_speed (Address: 81)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=81, count=2, unit=1)

if not result.isError():
    print(f"Raw Value: {result.registers}")
else:
    print("Error reading register")

client.close()

Integration (Home Assistant)

Paste this into your configuration.yaml:

- platform: modbus_controller
  name: "name_inverter_name_mppt_charger_fan_speed"
  address: 81
  value_type: U_WORD
  unit_of_measurement: "%"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Device Growatt Spf]

    PLC -- "A+ (D+)" --> Device
    PLC -- "B- (D-)" --> Device
    PLC -- GND --> Device

💡 Engineer's Insight

Analysis: MPPT charger fan speed. Units: RPM. Indicates cooling status for the Maximum Power Point Tracking charger.

Troubleshooting: Low/zero reading may indicate fan failure, obstruction, or a cooling system fault. Check for debris and motor operation.