My 6 months free supercharging period will end in a few days while I'm on a 1,200 mile road trip. I want to make sure I'm all set to continue using the supercharger network on my trip as a paying customer but don't know what needs to be done to ensure they will not stop charging for me. I would think Tesla would want a credit card number--or something--from me to be able to bill me. Anyone know the mechanics of paying for supercharging juice?