I also got to hand out with the Tesla owners after dinner.
They showed me how the charging system on the car works. There's a lot of neat aspects to it. The LED ring around the charging port changes color and the rate it pulses at to indicate what it's doing and the state of charge. The display screen in the middle says how many miles you are ready for on the current charge. (I think the one I was looking at said 216 miles!)
The charging system can also heat or cool the batteries, so that they are always at the proper temperature. The black car was charging at 40 amps, and the radiator kicked on for a couple of seconds at one point, the regulate the heat of charging.