You’re pre-installing a power lead for an unknown, TBD in the future, theoretical “accessory” in the trunk?
Why not just run a heavy gauge fused wire from the battery or power center and if you want it controlled by the key, install a relay that is triggered by any circuit that is ignition controlled?
There’s no point in trying to “use part of the power from an existing wire”. That would be like installing multiple small wires to the starter vs 1 large wire.
i dont want it switched ignition, i want it hot at all times(then run to a switch if anything but power ports) and no its not for a TBD im actively brainstorming some ideas since I got my refund and on buick forums weve gotten a list narrowed to
1) portable blender charging(not my idea, but a guy really wants his blended drinks at the beach lol)
2) a decent sized 12 volt air compressor which would be used for changing ride height manually or tire airing up.
3) DC cooler, but only smaller sizes would really be feasible
4)USB and 12 volt charging ports, would like to do this almost no matter what. marine grade probably.
5) Inverter(but it wouldnt be good for all that many actual applications)
6) Finally, power to support an auxillary backup lamps that can mount on my receiver for a hitch, ran to a switch. for reversing in the really dark and reminding tailgaters thats im willing to take us both out so back up lol
The power wire is already run half way down the rear quarter panel and the fuse is under the rear seat in the bused electrical center. i was saying fuse tap a 20amp and keep the original 10 amp wire and then i could run the new wire anywehre, say, opposite side of the trunk, and power a theoretical these lamps via the driver side and power an outlet center on the right side. thats the idea. im just not decided on what i want to put back there for certain