I have a 2007 A4 Quattro and all of a sudden it seems the altenator will no longer charge my battery. I repalced the battery and I can start the car for a few times until the charge in the battery goes down. I then charge the battery back up and again, can start the car until the battery goes dead again. I've checked everything I can think of, i.e. no corrosion on the battery terminals, the fusible link is fine and all the connections I can find seem to be tight. The car drives fine once it's started and everything seems to be powered fine so I'm fairly confident the alternator is working except for the fact it won't recharge the battery. Any ideas?

 

Test the alternator. It might be putting out just enough juice to keep the car running, but not enough to recharge the battery.