My sister has a 2007 V6, a few weeks after buying her car used (about 50k miles) the battery died. She went and bought a brand new battery but about a month later, she was driving on the hwy and her headlights turned off. Just stopped working! She pulled off the rd and turned her car off and it would not start like the battery was dead. Has anyone had this kind of a problem before? I had an 05 V6 and over 3 years and replaced my battery once. I'm wondering if it could just be her alternator or if there's some kind of underlying electrical :\ either way its not a fun situation

 

Go to an auto parts store, and have them check the alternator. They'll usually check the electrical systems for free. The car will start shutting off the electronics, if it's about to die. So that explains the headlights shutting off.

 

It does sound like an alternator that is under performing and the battery is having to carry an excessive load when it comes to providing juice...which fries the battery pretty quickly.