Always on USB ports.
 

Looking for some ideas that I can use in the rear cargo area. I already have 12v battery voltage back there, but I'm looking for something USB to add that won't add any drain to the battery.

You cannot have an "always on" USB outlet without some small drain on the battery.

Perhaps a better way to word your request is to ask for a minimal current drain USB outlet to which I can give you a more useful answer. :naughty:

For instance the Blue Sea dual USB outlet only pulls 0.015Amp which would take 3,333 hours to suck 50 Amps out of a battery.

12/24V Dual USB 2.1A Charger - Blue Sea Systems

If You already have 12 volts in the cargo area you can install one of these.
With the switch to turn it on when you are charging a devise and off when not.

Personally I'm not that seasoned with automotive electrical. I would rather never worry about my starter battery.

I use a battery pack from amazon for now. But, I will prob move to a goal zero or w.e. Charge it on the move and or get a solar charger.

Can't go wrong with a standalone IMO.

I've decided to just use a two port USB adapter in 12 volt socket. It's not something I'll use very much, so I can just unplug it when not in use.

Where can I get one like this and how did you wire it?

I got this from Amazon.

Go to my Album page I have a pictorial write up on this including how I ran the wire and what size. I also installed a Sub fuse panel in the wheel well. I show that also.
Keep in mind I have a dual Battery system that feeds a main relay and fuse panel under the hood. This feeds that sub panel in the wheel well.
The larger wire running from the engine compartment to the rear wheel well is fused at the main panel.
The sub panel has fuses that will protect the smaller branch wires to the plugs and protect the device plugged into it.

You don't need a dual battery system to install this but make sure you fuse the feed cable at or near the battery to protect the cable.
Then fuse the blue sea device at there location. I think the device comes with a inline fuse holder at the device.

This sound like over kill, but You need to isolated your electrical Mods from the OEM system as much as possible.