{quote} The other thing that concerns me about this valve is whether it is truly NPT threads. Some claim this, but I've seen this before where the actual thread was BSP - which is expensive to find matching fittings in the US. Have you bought any of these to check the fittings?{quote}
I'm in Australia. I've got a 20mm one filling from a dam water tank I pump up to, to a drinking trough header tank. maybe 20m head.
Australia went metric recently. Well bank in 1974, just 44 years back. However lots of plumbing fittings never converted. I can confirm the 20mm one is a standard 3/4 inch tap thread. Which is BSP. British Standard Pipe.
So you may be out of luck unless you can find a cheap and friendly chinese BSP to NPT adaptor.
My spreadsheet figured that the battery usage of the ball valve (sorry if that isn't the US term, but I still struggle with faucet to tap name mapping) suggested that at a couple of 4 second actuations a day was significantly smaller than the moteino current sleeping 8 minutes then doing a radio poll. The 30ma / 12V was measured, the 4s was estimated by watching it open. Although that power supply has an 11ma offset so maybe 20mA is closer the mark. Its as easy to swap and charge 3 LiPo batteries as 1 every year or so.
I'm sure your charge pump and double AA wins on elegance and size and efficiency, but you also have a higher component count. My solution got thrown together quickly on a very small piece of veroboard and components already in the workroom. (I'd bought the ball valve some months prior when I tripped over the add.
I've got a 1 inch motorized ball valve on order , interesting to see what that is like to actuate. That part of the home paddock irrigation leaks, I should turn it off too.
Do you know whether the latching solenoid requires significant water pressure to either actuate or hold? All the power-to-enable 24VAC kind I've played with need a few 10's of PSI to turn on. I only get that sort of pressure when pumps are running, which is infrequent.