After another auto parts store 'tested my battery and alternator' and sent me on my way with no problems found, I found myself stuck unable to start twice over the weekend. I decided to try a different place which happened to be O'Reilly. First thing they said, battery very bad. Good. Suspected problem confirmed. Then rather than sell me a battery and install it, they pointed out these cars with the new engine stop/start at traffic lights have two batteries! There's a small one that powers the aux equipment while the engine is off and alternator is not running at these annoying 'engine off' traffic lights. Their computer instructed them to send customer to professional (dealer) service for determination and replacement of proper battery, this to avoid accidental damage to computers. I can understand there must be circuitry that ties the output from the alternator to both batteries and there may be voltage somewhere you don't anticipate. So you could buy a battery and probably replace it at home being extra cautious but that's too much liability for a store which is not a service center. O'Reillys jumped the car, got me started and sent me on my way to my dealer, no charge. This made me have a bit more faith in them going forward than the other store in town. read more