Need advice on 50 ft cable to portable solar panel

ktmrfs wrote:
buy a 12Ga 3 wire extension cord, cut the ends off it and solder the green wire to either the black or white on one end do the same at the other end soldering to the same color you did at the first end.

Another approach is to make adapter plugs to go on each end and jumper the wires at the adapter. This way you have a dual purpose cable. Remove the adapters and use it as a regular 120 VAC extension cord.