USB behind the dash

If I tap a fuse that is only hot with the ignition on and used this 12v to 5v converter should I need anything else to run USB behind the dash?

 

Not an expert by any means but that makes sense to me...

 

Yeah your idea is fine.

I would splice into the cig lighter wiring because it’s built to power devices. Using add-a-fuse can be tricky and most of those circuits aren’t designed to have any additional load put on them

 

why not tap an always hot circuit?

 

Because all it takes is one time leaving something plugged in overnight and your battery is dead. If you’re running a dual battery setup or a solar panel on the roof or something, constant is preferred in my eyes. But for the typical person, they’re probably using a USB port in the dash for a GPS or some other device they’re only using while driving.

 

Yep just trying to clean up the wire situation.