EmsTechLabs Logo EmsTechLabs

Esp32 S3 Pv18 Usb Modbus Register 15203: PV Charger Charging state

Technical documentation for Modbus register 15203 on Esp32 S3 Pv18 Usb. Data type: INT16. Includes Python and YAML configuration examples.

January 16, 2026 1 min read

Technical Definition

The register PV Charger Charging state at address 15203 is used to monitor pv charger charging state on the Esp32 S3 Pv18 Usb.

  • Protocol: Modbus RTU
  • Data Type: INT16
  • 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 PV Charger Charging state (Address: 15203)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=15203, 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: "PV Charger Charging state"
  address: 15203
  value_type: INT16
  unit_of_measurement: ""

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esp32 S3 Pv18 Usb]

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


💡 Engineer's Insight

Analysis: Represents the current charging state of the battery connected to the PV charger. (e.g., Bulk, Absorption, Float, Off). Units: State.

Troubleshooting: Zero state implies charging is not occurring, possibly due to full battery, absence of solar input, or protection trip.