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Off-Grid Solar Management
Home Assistant ESP32 Must/Growatt Inverters Pylontech BMS
POWER_GRID: DISCONNECTED (ISLAND MODE)
True technological sovereignty requires energy autonomy. This project outlines the architecture of an isolated (Off-Grid) photovoltaic system managed entirely via software.
Base Hardware
- Hybrid Inverters: Must / Growatt.
- Lithium LiFePO4 Battery Banks: Pylontech.
- Solar Arrays: Configured in series/parallel to maximize MPPT voltage.
Telemetry and IoT Integration
The biggest issue with commercial inverters is their stock monitoring software (slow, dependent on third-party clouds, not customizable).
The solution: Extract data directly from the RS485/CAN port.
Using ESP32 microcontrollers flashed with ESPHome, we intercept the serial communication between the inverter and the battery.
# ESPHome Modbus register mapping example
sensor:
- platform: modbus_controller
modbus_controller_id: inverter
name: "Battery Voltage"
address: 10005
value_type: U_WORD
unit_of_measurement: "V"All this telemetry flows into Home Assistant, where custom Python automations dynamically decide whether to trigger heavy loads (water pumps, backup runs, secondary nodes) based strictly on solar production surplus.