Fixed it for you based on what my wife always tells me.

Recently used the long-term garage for a short 4 day trip. Found a charger on level 4 unoccupied, used one of the RFID credit cards to activate the charger and it only shut off after it hit the charge limit I had set in the car. Too bad from that point parasitic draw set in and by the time I got back the charge was what it was when I first parked it.

So the lesson here is make sure you're charging slow enough and long enough that the charger won't hit its limit and shut off. This also explains why so many of the chargers were connected to cars but not charging.