Aeroponic repeat cycle timer?

Quasar Jones

Quasar Jones

Member
Atomizer said:
Songle relays are really crap quality, the most reliable mechanical relay i`ve used is the HF3FF. It has a 12v dc coil and is rated at 15A for 125v.
The thing to remember with SSR`s is they only come in a single pole version, they need a heatsink if you draw more than a few amps and when they fail (which admittedly isnt very often) they typically fail closed circuit (permanently on).
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What's your experience with Songle? Limited life? I haven't had any issues yet, but when I make this a pcb, I plan on getting better quality. I did some math on the lifetime, and they will only last one year, but I factored that in to my process. This is more a proof of concept at this point.

With the Panasonic 25A ssr, the datasheet says it won't need a heat sink since my ac is only 500W. I ran it for an hour yesterday. I guess we'll find out. Failure is a part of the process.
 
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Atomizer

Well-Known Member
Quasar Jones said:
What's your experience with Songle? Limited life? I haven't had any issues yet, but when I make this a pcb, I plan on getting better quality. I did some math on the lifetime, and they will only last one year, but I factored that in to my process. This is more a proof of concept at this point.

With the Panasonic 25A ssr, the datasheet says it won't need a heat sink since my ac is only 500W. I ran it for an hour yesterday. I guess we'll find out. Failure is a part of the process.
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Songles lasted an average of 3 days with HPA, they literally fell apart internally :) If you pop the top off one you`ll see how cheap they are. For the sake of a few extra pennies its worth buying quality. Finder is another good brand. SSR`s are the best bet for anything that operates a lot of times a day, some of my timers run upwards of 1500 cycles day which would wear out a mechanical relay pretty quick. SSR`s can handle 30-50 million cycles. If you ran a constant 1 second on and one second off, it would last 2-3 years :)
 
Quasar Jones

Quasar Jones

Member
Atomizer said:
Songles lasted an average of 3 days with HPA, they literally fell apart internally :) If you pop the top off one you`ll see how cheap they are. For the sake of a few extra pennies its worth buying quality. Finder is another good brand. SSR`s are the best bet for anything that operates a lot of times a day, some of my timers run upwards of 1500 cycles day which would wear out a mechanical relay pretty quick. SSR`s can handle 30-50 million cycles. If you ran a constant 1 second on and one second off, it would last 2-3 years :)
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Oh, gotcha, I use a transistor for anything DC, so the solenoid. Which is the one im guessing failed for you. Relays are overkill for small DC components, imo. No moving parts to fail in a transistor, and they're like 10 cents.

I had to add beefy pull down resistors to my songle relay input lines, otherwise they would resonate, or whatever, terrible buzzing noise, and it was actuating like 10 Hz, when the max is like .5 Hz. Still using them. Its important to have reversed diode across the load to to suppress arcing/contact wear. The relay module I linked too already had that built in.

Jesus, what are you running one second on/off? If it's DC try a powerfet.
 
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Atomizer

Well-Known Member
I dont use 1sec on and 1 sec off, it was just to highlight how much abuse an SSR will handle ;)
The flywheel diode is important as it prevents back emf from damaging sensitive components, as the magnetic field in the relay coil collapses it creates a reverse voltage. If you use a DC SSR you need a flywheel diode across the output when using inductive loads such as solenoids,motors etc. Most have them fitted internally but its worth adding one. The bonus with SSRs is they switch faster, are silent and have no contacts to bounce or arc
 
Glider

Glider

Member
Atomizer said:
I dont use 1sec on and 1 sec off, it was just to highlight how much abuse an SSR will handle ;)
The flywheel diode is important as it prevents back emf from damaging sensitive components, as the magnetic field in the relay coil collapses it creates a reverse voltage. If you use a DC SSR you need a flywheel diode across the output when using inductive loads such as solenoids,motors etc. Most have them fitted internally but its worth adding one. The bonus with SSRs is they switch faster, are silent and have no contacts to bounce or arc
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I have been getting ready to use a Sestos Digital Quartic Timer but on another subject. Could you tell me what novels you use and where you get them also what kind of a pressure pump you use. I am not happy with the system I have which is based on pressurized air
 

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Atomizer

Well-Known Member
I guess you mean nozzles :) I use different kinds, for long narrow chambers i use netafims and for square one i use hypro`s. The same goes for pumps, i have an aquatec 6800, 8800 and a beefy12v dc pump thats good for 4LPM at 160psi. I also have a manual pressure pump that needs no electricity to delivers upto 750psi at 45ml per stroke ;)
I prefer to use pressurised air for aero, its much more controllable than pressurised water..
 
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Atomizer

Well-Known Member
You need the skills of a safecracker to hit the same setting twice on most timers equipped with pots/knobs. Where a fixed timer doesnt fit the bill, go for one with rotary swiches or a digital readout
 
Quasar Jones

Quasar Jones

Member
Atomizer said:
I guess you mean nozzles :) I use different kinds, for long narrow chambers i use netafims and for square one i use hypro`s. The same goes for pumps, i have an aquatec 6800, 8800 and a beefy12v dc pump thats good for 4LPM at 160psi. I also have a manual pressure pump that needs no electricity to delivers upto 750psi at 45ml per stroke ;)
I prefer to use pressurised air for aero, its much more controllable than pressurised water..
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Does the 8800 aquatec go up to 160 psi??? I looked at the datasheet and it didn't really indicate that. I want to go up that high and was thinking I could only use a shurflo...

http://www.aquatec.com/booster-pumps.html
 
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Atomizer

Well-Known Member
i`ve never tested how high the 8800 will go but the 6800 is good for at least 125psi, i use the aquatecs cos they`re ultra reliable and very quiet runners ;) My beefy 160psi pump makes more noise but its rugged and reliable, it does 6lpm open flow and 4lpm at 160psi, being a dc pump its immune to power outages. Both my aquatecs are 24v ac. Always check the spec sheet before buying a pump, its no good having a pump that does160psi if it only delivers a dribble of flowrate at that pressure :)
 
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