This is beneath the qualifications of pretty much everyone on this site I think, but I figured I'd post anyways and see if anyone had some good critiques or suggestions for how to do this a better way.
I've got 2 cameras in my vehicle that offer a 24/7 recording option that loops just in case there's an event while parked. I've tested them to use about 11 watts constantly each, and because they have no programmable shutoff for the current state of the battery I definitely don't want them feeding from the car's electrical. I've explored programmable relays that will drop out at 12.6V, which is significantly better than letting the battery drain, but idle these devices will still quadruple my car's stock power draw due mostly to their bright displays.
I've moved on since then to using a power bank typically used for tablets and phones and it works great, however I need one that can supply 11wx2 at once whether charging or not. The one I have seems to be teetering on the edge of what the cameras require since sometimes one will drop out and go into a reboot loop. The idea is to let the car fast-charge the bank while it's on and then if the bank goes dead it goes dead, but most of the time it will be charged enough to record the parking lot. This isolates my car's battery completely while still giving days worth of recording.
The question is for a USB 3.0 or 3.1 port, if you use a 2.0 cord will the power delivery still be 3/5A respectively through that old wire? I understand that I'll be missing 5 pins when using an older standard plug. The 2.0 ported power packs I'm seeing (and own) provide 5V 1A hookups, but even 5V 2A would be barely enough. I suspect when it goes through its new file compression sequence it might exceed the rating of the bank. USB ratings are a right mess lately from what I can tell.