Architecture

Main components

flowchart TD
    GS[HA Grid Sensor] --> CC[ChargeDischargeController\n__init__.py]
    CC --> PD[PD Algorithm]
    PD --> DIST[Power distribution\nmulti-battery]
    DIST --> MW[Modbus write]
    MW --> BAT1[Battery 1]
    MW --> BAT2[Battery 2..4]

    COORD[MarstekVenusDataUpdateCoordinator\ncoordinator.py] --> MR[Modbus read]
    MR --> BAT1
    MR --> BAT2
    COORD --> EU[HA entity updates]

    MC[MarstekModbusClient\nmodbus_client.py] --> MW
    MC --> MR

Modules

File	Main class	Responsibility
__init__.py	ChargeDischargeController	Main control loop (every 2.5 s), PD algorithm, multi-battery distribution
coordinator.py	MarstekVenusDataUpdateCoordinator	Periodic Modbus data polling, entity updates
modbus_client.py	MarstekModbusClient	Async TCP communication via pymodbus, retries with backoff
config_flow.py	—	Multi-step configuration wizard in HA UI
const.py	—	All Modbus register and entity definitions
aggregate_sensors.py	—	System aggregate sensors (sum across all batteries)
calculated_sensors.py	—	Derived calculated sensors (cycle count, estimates)

Data flow

Grid sensor → Controller (PD) → Power distribution → Modbus write → Batteries
                    ↑
Coordinator → Modbus read → Entity updates

Polling intervals

Interval	Period	Registers
high	2 s	Power, SOC
medium	5 s	Voltage, current, temperature
low	30 s	Accumulated energy, alarms
very_low	300 s	Device info, firmware