Device Growatt Spf Modbus Register 18: Name inverter name battery soc

Technical Definition

The register name inverter name battery soc at address 18 is used to monitor name inverter name battery soc 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_battery_soc (Address: 18)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=18, 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_battery_soc"
  address: 18
  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: Battery State of Charge (%). Percentage of battery capacity remaining.

Troubleshooting: Zero if battery is fully discharged, disconnected, or BMS communication failed. Check battery status and connections.