OK Phase 2 of the simple trailer project that I over complicated.
So you have a winch you need power. I decide to keep it separate from the tuck and add an independent second battery.
Since you hardly ever use the winch it seems shame to waste all that power. So I rummaged around my shop and found an old control box from an AC unit - turned into a fuse box - before anyone makes wise cracks about the pill bottle. The winch came with an in line 50 amp fuse - I didn't want it bouncing around in the box so I made a red neck fuse holder.
Added a Battery Meter and used an old trolling motor plug to make a charging port. Bent up wire bracket to hold the charger up off the floor.
Quick disconnect for the Winch - Tomorrow a new electric jack for up front
All I have left to do is make the hitch bar for the front of the Sling and test