Esp32 Pv18 Modbus Register 25275: Inverter Battery grade

Technical Definition

The register Inverter Battery grade at address 25275 is used to monitor inverter battery grade on the Esp32 Pv18.

• Protocol: Modbus RTU
• Data Type: S WORD
• Unit: V
• 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 Inverter Battery grade (Address: 25275)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=25275, 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: "Inverter Battery grade"
  address: 25275
  value_type: S_WORD
  unit_of_measurement: "V"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esp32 Pv18]

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

💡 Engineer's Insight

Analysis: Reflects the battery's charge level or health status, likely as a percentage or grade.

Troubleshooting: A low or 'error' grade suggests battery issues (sulfation, age, damage), Temperature problems, or BMS fault.