On this dead battery posts...I have a 27,000 mile, 2015 Explorer Limited. And yesterday afternoon I plugged in my shorter phone charging cable into one of the HDMI connections and no phone connected and went back in the house. Maybe an hour or 2 later we are leaving for a party and went to start it....no go....sympton dead battery. Tried cranking a couple times....no go. Sat there a minute and thought only thing different is installing that charging cable into the HDMI port.....so pulled it out of the port and it fired right up. Went to the party and there was a Ford Tech there and he mentioned after conversation with him that is a typical problem....there is a constant/direct power supply to those ports. So best to use only while vehicle is in operation.
I assume when you wrote HDMI than you meant USB port (socket)? Plugging a cable into that without a phone connected should cause no power draw at all, electrically should make no difference, unless the cable itself or the socket has a defect or damage that causes it to short out.
If it shorted out, there should have been a fuse blown or it would fail. A blown fuse should cease excessive power draw and not result in the battery not having enough power to start the vehicle if it otherwise had good margin. A failure would be as you'd expect, the USB port would no longer work. I suppose there is a 3rd possibility, that it uses a resettable fuse but that seems least likely in this application/circuit.
Due to these things, your report seems very unusual. When I get a chance I can check on whether my USB ports in my '14 stay powered when the vehicle is off but as above, there should be no power draw with nothing attached to the cable (maybe 5mA (a trivial amount) if it's one of those fancy cables with an LED in it to indicate power but those are rarer these days).
Further, whatever power might be drawn once a phone is hooked up, is gone *forever* (until the vehicle starts and the alternator recharges the battery), should not result in the vehicle being able to start once the cable is unhooked.
Even though everything I wrote suggests something else is wrong, I would still expect that your battery is nearly at the end of its lifespan. The factory battery in yours is now at about that age.
Previously I wrote that my '14 battery still works, but ironically a few months later it showed signs it was struggling, so I replaced it last winter.
Something noteworthy is that Walmart, where I got their replacement Maxx group 65 battery, was going to put in a smaller battery with lower CCA yet it cost even more than the group 65.
A group 65 fits perfect in my '14, glad I caught that they were going to put the smaller battery in, BUT there is a battery insulation sleeve (foam and fabric construction) that Ford put around the original that is too small for the group 65 battery.
Since I don't operate the vehicle in arctic cold nor desert hot temperature extremes, I much preferred having the larger battery over retaining use of the insulating sleeve... and even then, a lot of vehicles in those temperature extremes don't have a battery sleeve, particularly in cold weather the extra CCA's might help more. IIRC Walmart's Maxx 65N was $93 +tax for 850CCA and a 3 yr full replacement, 5 year prorated warranty and was made by Johnson Controls.