Electrical woes

[wsmeyer]

2008 X5 4.8 died on my wife yesterday morning. It started, drove just fine with no warning lights and then suddenly 4x4 and other warning lights and as she was pulling into a parking spot it completely died.

At this point the battery was almost completely dead, can't remember but 11 point something volts and the car would reset when the start button was pushed. While removing the battery I noticed the negative terminal was corroded and slightly loose.

I charged the battery up with an AGM compatible charger and it was at 12.7V. Cleaned the terminal and reinstalled. Car drove just fine, no warning lights. Two trips yesterday afternoon roughly 15 miles total with no problems.

This morning the wife takes it and it dies again less then a mile from the house.

I'm going to charge the battery again and take it to Autozone and have it tested as it's only about one year old but really having a hard time wrapping my head around the fact that a battery has enough power to start a car and then die less then a mile later. These have warning lights if the alternator isn't working right?

Any ideas welcome!

William.