Well like I said the flickering is no longer a problem. As I turn the button on the VR, it goes from having zero effect at the battery to taking it up to about 17 volts.
I’m just wondering about optimal workings under load and temp, etc.
I still don’t have a clue what the field effect coil does.
A fully charged battery should be between 13.5 and 14 volts. Anything higher will burn it up quicker.
Without knowing the current you're drawing it's hard to know what your actual load is. Do you have an ammeter?