I've decided I want to install a 2nd battery setup in my F-150 Supercrew. From the battery to the back of the truck in a straight line where I plan to put the battery it's 19'. I plan to run the cable down to the frame, under the truck and then up through a small hole in my bed, probably be about a 25' run when done. My question is what gauge cable should I use to run from my engine compartment to the battery at the back of my truck? I'm thinking 2 gauge welding wire should do the trick. The reason for welding wire is it uses smaller strands of copper making it easier to work with, also means more copper than standard battery cable with thicker wires. Have any of you ran a similar distance and if so what gauge have you used successfully?