I have built my own systems and done a bunch of head scratchin over these issues. Right now your valve is on or open as long as engine runs allowing
oil pressure to flow if needed but needs you to turn off before engine shuts down (this keeps pressure for next start up). This is using Hot side of battery to open/close the solenoid and it needs power as long as engine is running so they sometimes get a little hot, plus a low battery turns it all off.
If you add a pressure switch, relay , red warning light for dash mount and push button switch you could have it work like this. Turn the key to on position and push the button to prime the system then start her up. Push button again to fill the accusump with engine running. Now because it is wired through the pressure switch and dash warning light no electric draw is needed until engine pressure drops. If the pressure drops it closes pressure sensing switch and automatically dumps
oil into engine but also turns dash light on so you know a problem existed. My system refills the sump automatically so you do not need to manually refill sump or remember to turn solenoid off so you have a charge for the next start up.
Wire the relay to supply hot to the solenoid from the ignition and turn system on/off with the ground signal. The adjustable pressure switch set at say 20 PSI will trip if
oil pressure drops or if you push the button switch also suppling a ground. The dash light also uses this ground signal to warn you if pressure is low causing the A-sump to supply oil to engine. No hot solenoid or no current draw until it sees low oil pressure and turns itself on, plus you do not have to remember to turn system off so it saves pressure for next start up. works great.
PS My solenoid will not loose a drop of pressure even after weeks in the trailer.