I have concluded that a solar powered system is NOT a viable system for N. Ireland. (No shit Batman) So I have taken a slightly different approach, by using a higher capacity battery and using a micro irrigation system the problem is solved, at lease I hope this is so.
One like this that can be had for as little as £7 from my favourite store Lidl. Now the plan is…
So you get your low-pressure watering system and use a low current solenoid, with the 7A/h battery you can be gone for 2 maybe 3 weeks.
The low current solenoid attaches to the low-pressure piping perfectly.
Then you can just go out a buy a £20 tape attached, battery powered time controlled watering system, but where is the fun in that?