my car radio cuts out and after leaving the car sitting for a few hours, I try to start it but it won't and nothing works. All of the indicators, radio, lights. No power what so ever. I brought it in and I was told it was the battery, a few weeks later it happened again. Brought it in again, they have no idea what it is. To me it seems like the alternator is draining the battery but they said it isn't the alternator. What else could be the problem and how can I check for myself?