I had posted on the previous forums and received a great deal of good advice which allowed me to take my project past proof of concept phase. At this point I'm actually planning to try and impliment what I've investigated.
Long story short I am using a circuit quite a bit like the one here. http://www.beam-wiki.org/wiki/1381-based_Solar_Engines Only replace the motor with a solenoid valve to allow a few seconds of water flow upon command. (Which will have the ardunio controlling a component in the circuit to control when to allow the solenoid to open, but only when sufficient power is available.
Now my test of this circuit (proof of concept) worked wonderfully and I was actually able to run a high speed motor off the setup and it would run for several seconds before draining the capacitor. (4700uf)
Now here's the tricky part, I'm preparing to buy the final test parts. I know I will be getting a differen 1381 unit to correspond with the solenoid valve... there in comes the trick. On my last post someone had linked me a few solenoid valves but since then the "ideal" one has become a bad link. I'm only looking at pushing a little water at a time which will be gravity fed (I can provide pressure behind the valve to help "crack" it if gravity won't suffice) But basically I'm looking for a low voltage, cost effective valve I can use in my project.) If this test works out for the first length of the system as time goes on I'll wind up adding more and more to it.
(Project is "GOATEE" Garden Operations Automation Through Excessive Engineering) This segment detects moisture in the soil, compares against soil tempature, and then waters plants per need based around the ardunio board. So far I've got the watering well along the way (above) and my moisture sensor is working, but still a great deal of fine tuning to do before it is ready to run the show on determining when to/not to water the plants. I'm moving into my home in a few months and plan to setup the system with my garden as I build it :) Really enjoying this project. Any help you can provide in ways to improve the above, or pointers on a trust worthy source to get a reasonable valve would be wonderful!
(edit was ninja spelling fix)