12v Motorised valve from China with supercap

[Dankoozy]

I bought a few motorised valves from China so i could make my own heating controls and run them off 12v. These are much cheaper than the 230v mains motorised valves that are common here in Ireland and usually have a spring return on them and continously waste about 6w of power running the motor stalled just to counteract the spring.

But anyway I hooked it up to my power supply to see if they were any good and could not hear any obvious spring return mechanism. So I decided to have a peek beneath the cover as you do and saw they put in a little 5v/1F supercap and some power conversion circuit that has just enough juice to close the valve again once you remove the power supply. Kinda neat

[Gyro]

They look a bit fragile compared to standard mains ones, what's the temperature spec?

Agreed, storing enough energy to close again is a neat idea (assuming that they still make it as the valve ages and stiffens). The spring and motor arrangement on the mains ones is wasteful in modern context.

[Dankoozy]

They look a bit fragile compared to standard mains ones, what's the temperature spec?

Agreed, storing enough energy to close again is a neat idea (assuming that they still make it as the valve ages and stiffens). The spring and motor arrangement on the mains ones is wasteful in modern context.

80 degree or 100 depending on which eBay listing you look at

I suppose one could stretch the life of it by embiggening the supercap if it became a problem

[Gyro]

Ah, the old seller 'how far can we plausibly push it' specmanship battle on the same product. 

There should be a temperature drop between the water passing through the valves and the electronics (as long as you keep them well ventilated). It's probably worth checking the temperature specs on the electrolytics and supercap, though I suspect that they will be ordinary 70'C.

If it comes to it, failure to fully close is probably a much better than failure to open!