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Esp32 C3 Zero Epever Modbus Register 12550: Charging power

Technical documentation for Modbus register 12550 on Esp32 C3 Zero Epever. Data type: U DWORD R. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register Charging power at address 12550 is used to monitor charging power on the Esp32 C3 Zero Epever.

  • Protocol: Modbus RTU
  • Data Type: U DWORD R
  • Unit: W
  • 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 Charging power (Address: 12550)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=12550, 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: "Charging power"
  address: 12550
  value_type: U_DWORD_R
  unit_of_measurement: "W"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esp32 C3 Zero  Epever]

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


💡 Engineer's Insight

Analysis: Shows the instantaneous power used for battery charging. Units: Watts (W).

Troubleshooting: Zero if charging is off, battery full, or power measurement circuit issue.