I aN GROWING CONCERNED ABOUT MY HPWC. I have had the car and charger for almost a year. For the second time it has stopped working. The first time TESLA came out and fixed it. This time they say they are sending out an electrician to change it because they can not fix it. Fortunately it is under warranty. It is a great car but very disconcerting if i am unable to use it. Have others had many issues? Do most get a back up 40amp wall charger installed as a back up? Has anyone compared charging through 40 amps vs 80 as far as cost and efficiency?