2016 Tech P-AWS, had for 9 months. Got a new battery through the dealer but to my knowledge they didn't change the battery sensor. Fast forward to last Saturday when I drove it, it cranked just fine. Went to leave for work Tuesday morning and nothing, no courtesy lights, trunk wouldn't open, its like the car was completely dead. Got home from work and used a portable jumper and it started like nothing was wrong. Took it to O'Reilly's to get a battery test done and he said the alternator was bad. Should I take it to the dealer or just replace the alternator? Could the battery sensor be bad since its cranking like nothing ever happened?