Is the guy at Advance Auto full of it?

[Huskymaniac]

Here's the story. I went to pick up my son after his cross country practice. It was a nice day out so I turned off the car and listened to the radio (about 25-30% of full volume) while I waited. His bus was pretty late getting back. I was sitting there for about 30 minutes. The only other thing that was running was the blower fan which was on medium. The battery weakened to the point of not being able to start the car. I thought that was a bit too fast so I decided to just walk down the street to Advance Auto to buy a new battery. The guy there said that a battery older than a couple of years would probably not be able to hold a charge under those conditions for 30 minutes. That seems crazy to me. I know a car battery is made for cranking and not deep cycles but it should have more AH than that, no? One thing to note is that the battery in the car is one from Advance Auto and it still under partial warranty. Sounds like they don't want me to return my weak!$* battery.