Usused fuses

[JoeN]

My truck came with fuses in some of the slots for options I do not have.... like a winch, and airbags.

From what I can tell, these are switched circuits and at least the winch is a 20amp circuit.

Any danger in running some additional 12v outlets and USB charging outlets off something like the winch circuit via an "add a circuit" fuse adapter kind of thing?

 

[Distillusion]

As long as you've run wiring of the appropriate size for the load, and the fuze is sized appropriately, and you've done solid work, there probably is no danger. Most problems come from under-wiring (using wiring too small for the current load), bad splicing, and fuzes way oversized. I might be concerned about alternator limits. The size of your alternator and your normal load on it will give you an idea of how much "headroom" you have.