Yesterday after diinner I decided to clean the glass and interior of my car and of course had the doors open the whole time. I know the lights turn off after a length of time so I didn't think anything of it. I have had no indication of any issue with the battery before this.
Well this morning I put the key in, hit the button and all I get is that moan sound we all know when there isn't enough power to turn the starter over. I looked at the little battery status window and it is as black as it can be. I get out the jumper cables and jump it from another car. Then I get on the phone shopping for a battery. Dealer has one for $497 and only one other place has a battery on hand. They weren't a whole lot lower. It ended up costing $364 tax and all.
God I love this car.

 

You can try to get the dealer to cover it under warranty.
Will

 

I called them to ask if the battery was covered under the CPO warranty and of course it's not. It would have been nice but I wasn't expecting it to be.