In this post I will show how I control external relays from the Venus GX.
I use the Sonoff 4CH Pro with the Tasmota firmware for my installation.
As an example I have created a python script that turns on Relay 2 on the Sonoff if the battery voltage drops below 24.5V. The ip_address in the script is that of the Sonoff.
The attached video shows this in action when I turn on a load to force the voltage below 24.5V.
Python script:
#!/usr/bin/python -u
from functools import partial
import dbus
from dbus.mainloop.glib import DBusGMainLoop
import gobject
import urllib2
ip_address = "192.168.1.9"
def track(conn, value):
if value["Value"] < 24.5:
response = urllib2.urlopen('http://%s/cm?cmnd=Power2%%20ON' % ip_address)
def main():
DBusGMainLoop(set_as_default=True)
conn = dbus.SystemBus()
conn.add_signal_receiver(partial(track, conn),
dbus_interface='com.victronenergy.BusItem',
signal_name='PropertiesChanged',
path="/Dc/Battery/Voltage",
bus_name="com.victronenergy.system")
gobject.MainLoop().run()
if __name__ == "__main__":
main()
Hope this was useful.
Video: https://www.dropbox.com/s/gzetzcujomniedl/2020-04-30%2018.25.29-1.mp4?dl=0
Tasmota firmware: https://github.com/arendst/Tasmota
How to flash custom firmware on the Sonoff: https://youtu.be/UDnNI5wkNNY
