Has anyone used the Sonoff dual as a timer switch? I’m hoping to use this as a control for my main grow light as well as to turn on a far red flower initiator. It seems that this thing will provide a more accurate timing than a mechanical device. I’d like to turn on the far red as the main light is turning off. It seems simple enough, it can be controlled via a smart phone and the timer function does not require connection to a network once it is programmed. Fairly inexpensive to set up a timer box with the controller and a couple of outlets.
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I have a couple of sonoff relays. I had a dual running my lights and irrigation pump. It only lasted about 20 days. The other ones are still working after a couple of months though.
It worked ok, but could have been much better in my opinion. Some simple software changes would have improved it a lot. Like being able to set schedules with minutes and seconds or use the loop timer with the regular schedule. Being able to have the pump come on while the lights were on and turn on and off with the loop timer would have been great. Instead I had to use two relays. One to supply power to the other when the lights were on the other to run the loop timer.
They’re open source so if you are a programmer you could probably make them do what I wanted.
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I’m not a programmer so I kinda liked the simplicity of the plain vanilla timer. I just need two that would be synchronized. Any idea why yours stopped working? Do you think the single switches are less prone to problems?
I probably fried it. It’s 10 amps max and my lights draw right around that much. Plus probably a spike when they turn on. I thought it would have a little bit more of a safety factor built in.
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i’ve seen digital timers with multiple outlets that can run multiple schedules as well, you may be able to find one that can do what you’re wanting. this one is $20
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I don’t think my current draw is anywhere near that so I think I’ll give it a whirl… thanks!
I need that timer. @legalcanada just won yourself a free sandwich.
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Some relays requiere a Heat sink even below the máx amperage. That is How they burn up. Ask me How i Know.
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Hi @2RedEyes
I use a TH16 to switch a humidifier in “Auto” mode (on between a set RH range)
I also run 2 x S20 plugs for managing a large 2k heater on a timer and earlier on in my grow a dripper system to feed my seedlings.
The only negative with the software is that you cant run a loop timer within a scheduled timer, ie i want my heater to come on every 60 min for a period of 15mins (loop timer) but only between the hours of xx:xx (scheduled timer)
I also have a sonoff SC which is an overall environment reporting manager, which can switch other sonoff kit based on its detected ranges of… I dont feel this unit is reactive enough to manage things like temp control or RH as the reaction time is too slow, but its good as an overall summary of conditions where its mounted…
There have been issues with server downtime over xmas new year but they seem stable now, but the device just carries on doing whats been set, as long as it has power 
I love the remote app management and would give 8/10 overall
Happy growing 
Your lights are rated by average usage, when they turn on they can draw more current. Depending on the type they can draw double their rating when first turned on.
As such, I always rate my relays to double the wattage printed on my lights to avoid blowing them or welding the contacts together.
I would suggest a 20A relay for your lights or split them across 2x10A relays to avoid blowing anything in the future.
They sound like solid state relays that need a minimum amount of power flowing through the contact (not coil) side to operate. They get quite hot AFAIK.
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