aiosaj

Async Python library to read live data from SAJ solar inverters, over either their Ethernet (LAN) interface or their WiFi module. It was written for Home Assistant but works in any asyncio application.

aiosaj continues the work of fredericvl/pysaj.

Installation

pip install aiosaj

Requires Python 3.9 or newer.

Usage

import asyncio

from aiosaj import SAJ, Sensors


async def main():
    # WiFi module: wifi=True, with the module's web login (admin/admin by default).
    # Ethernet: SAJ("192.168.1.100") - no login needed.
    saj = SAJ("192.168.1.100", wifi=True, username="admin", password="admin")
    sensors = Sensors(wifi=True)

    if await saj.read(sensors):
        for sensor in sensors:
            if sensor.enabled:
                print(sensor.name, sensor.value, sensor.unit)
    else:
        print("Inverter not reachable (it switches off when there is no sunlight)")


asyncio.run(main())

• read() returns True when new values were read, and False when the inverter cannot be reached. SAJ inverters run on solar power, so this is normal at night.
• sensors["total_yield"] looks up a single sensor by name.
• sensor.enabled is True for every sensor your inverter actually reports. Sensors for channels your inverter does not have, such as a third PV string, stay disabled.
• saj.serialnumber holds the inverter's serial number after the first read, if the inverter's firmware provides it.

Use Sensors(wifi=True) together with SAJ(..., wifi=True), and Sensors() with an Ethernet connection.

Sensors

Both interfaces

Ethernet only

WiFi only

Older WiFi module firmware only reports the sensors that both interfaces have.

How values behave

• Values are only updated while the inverter's state is Normal. While it is starting up, waiting or in error, live values such as power and voltage become None, and the energy and time counters keep their last value.
• total_yield, total_time and total_co2_reduced never go down, and today_yield and today_time only go back to zero when a new day starts. This keeps energy statistics, such as Home Assistant's Energy dashboard, free of false spikes.
• A reading that is out of range or clearly wrong is skipped, and the sensor keeps its previous value.

Credits

aiosaj builds on pysaj by @fredericvl, which was in turn based on the pysma library by @kellerza.

License

MIT, see LICENSE.