Maximum Number of Zones

[astrogerard]

Sorry for the late reply... had some other stuff to do...

- use separate power supplies for the Pi, relays and valves. Since the (right) relay boards have optocouplers there is separation of power and logic. --> for the 5v relays a 1 or 2A usb charger can be used (I do so for many years)

- The master-valve relay can be used to switch on/off the transformer for the valves (reduced power consumption)

Hello Gerard,

Thanks for the info. I completely understand about having other stuff to do life has kept me busy the past week or so.

In the process of ordering the parts today and had a question or two about powering the relay boards.

1. Would I need one power supply for each relay board or can the power be daisy chained between the relay boards.

2. Would a 5v 10amp power supply work better than a 5v 3amp or would that be overkill? 

3. Maybe this should have been my first question but just verify that the 8 channel DC 5V Relay Module w/optocoupler will work with 24v hunter or rain bird valves.

Hope you are well and thank you again for your time.

The relay used on these boards is mostly a jqc-3ff. The 5V type has a coil resistance of 70ohm. So the current is about 72mA. To be on the safe side say you need 100mA per relay. If all 8 relays are on you need 800mA. So a psu of 1A should be sufficient for one board. For 3 boards with all relays on you never need more than 3A. I doubt if you ever will turn on all 24 relays at the same time but with a 5v 3A psu you can safely do this.

The relays are more than capable to handle the 24v valves. I myself use 24v rainbird valves for many years without any problems.

Hope this helps a little :-)

--Gerard