Hi
I am planning to make irrigation system using a wifi controlled board from SONOFF. I have watched Csongor Varga YouTube tutorial (https://www.youtube.com/channel/UCdRpPAsQbIaVpn_vS2_omPw) and planning to do the same thing with small modification.
since our valves working on 24VAC so I had to use a transformer from 240VAC to 24VAC.
The hardware to be used are:
Sonoff 4CH PRO R3
Sonoff Basic R3
Transformer 240v/24v AC
4x Valves
240v AC MCB
Water Pump in my case
I have made the following drawing to easy understand my project.
I am seeking expert comments on my design from electrical point of view. because I am not familiar with electrical wiring . or maybe you have improved recommendation to this design.
Just be mindful of the perils of WiFi/cloud. Turning on a valve and there is some sort of melt down - your valve stays open… I use a similar idea except with zigbee relays but include a hardware deadman switch to limit run time to 30 minutes. To overcome some of the limitations mentioned on the video you might want to consider this project:
This topic isn’t new, but I just recently got a garden which I’m now trying to water in a smart way.
I bought the valves and the sonoff and while the software part will be an issue of future me, I’m currently struggling to purchase the right hardware to power everything.
Could you kindly guide me to a) a 24v ac power supply which can handle 3 valves (Gardena) and b) let me know which fuse should be used to make this save?
My current plan is to draw 230v from a power plug in my cellar and connect this as shown to the sonoff as well as the fuse while also using a 24v trafo for the valves.
While I’m aware that anything discussed is my own risk, I only find 24v ac parts that might do well for a doorbell, but not for this use case, but I could be wrong.
You can find easily a power supply on Digikey. I do not know where you live but they deliver in 48h anywhere in Europe from their USA warehouse. I use the Mean Well power supplies since many years for electric actuators in a green house (very hot and a lot of moisture !!) and they are all still working well. They have a range which is IP68, 100% waterproof.
I tried to find the watt or Amp of the Gardena valves but I didn’t succeed to find it. I guess this will be maximum 1 Amp per valve. Count 1.5 Amp to be sure. So, for 3 valves, you are OK with a 5 Amp power supply ;).
For the fuse, go for a 10 Amp as this will be for short cuts and/or overheating circuit.
I am interested in doing exactly the same with the Sonoff 4CH pro (Without the Basic as well)
My question is regarding that transformer (CUB1), does it hold up though? I see it is only rated at 8VA .
I have 4x Rainbird HVF valves and as per their datasheet the maximum inrush current is 0.29A per valve so if I would be switching all of the zones on simultaneously you are looking at about 27.84VA (0.29A x 4 x 24V).
Even at holding current of 0.091A per valve you are looking at 8.736VA (0.091A x 4 x 24V)
Would it not be better to use at least a 30VA transformer for this application? Would the 8VA transformer not burn it’s coils operating all zones?