After over 56K miles and probably over 100 Supercharger sessions I have never had a problem connecting to a Supercharger stall and having charging start. I use no special "tricks".The OP said that he tried 4 different Superchargers and failed to get any of them to work. Granted, he's a new owner w/o experience, so it's not a huge red flag. But it's still not reassuring. Then another poster in this thread said that the trick to getting it to work it to push in the connector "quickly". This advice is far from intuitive or normal-sounding, so another worrying data point, IMO.