2012 chevy tahoe....dead battery. Took in 3x, tested battery/ alternator no pro

Hi! This is Bo with Car Genius at RepairPal! Sorry to hear about the no start! It sounds like you may have an intermittent draw on the battery. Figuring these things out takes a lot of time and can be tedious to say the least! You may have to find someone that is willing to keep the car and consistently test it for an intermittent draw throughout the day until they catch whatever it is that is causing the battery to drain. Some of the most common causes of battery drain are radios, HVAC head units, interior lights and any other electrical items that may stay on after the car is shut off. If you have any other questions feel free to call us at 877-913-1554! We'll be happy to find you a certified RepairPal shop in your area!