Lawn watering system

Shelly RGBW is an DC device so it won‘t work.

But a Shelly RGBW2 delivers a PWM signal, which can be interpreted as a kind of AC signal. Set to 50%, the 4 outputs furnish each an „AC signal“ of approximately half of the supply voltage. E.g., with 24 V DC supply, we get an 12 V AC signal. But the frequency of the signal is 1kHz (mains voltage has 50Hz). If this would be compatible to the Hunter valves should be tested…

thgoebel the RGBW2 is a DC device and it does not deliver a kind of an AC signal, it cannot simply be interpreted as an AC "signal"; you for yourself can redefined the zero to your half DC voltage and see "zero-crossings" but the AC devices wont care;

if the RGBW2 is being used, use VDC 9V from hunter as solenoids, then you can operate on 12-24V DC and get approx 9V if you dim right, for a slow consumer this might be ok as it doesnt really see the 24V which could be out of spec

A simple condensor in series to the valve coil furnishes a symmetrical square wave in relation to zero volt, if PWM ratio is set to 50:50.