I have high powered LED floods in the back bumper. Wiring them was the same as wiring any accessory light up front, with the exception that you have to be really careful how you route the wiring from front to back, ensuring that you don't put it anywhere it will get pinched, or cut, or caught by a stick/brush, rock, etc. I ran mine in black plastic wire loom along the driver side frame rail and body, zip-tying it glue-on clips every 12 inches or so. Definitely use good automotive grade stranded copper wire and solder joints if you can. Crimping and heat-shrink tubing is an acceptable alternative. The diagram above is helpful to an extent, but the SPOD makes it simpler.

This makes it simple.