I have 2001 1.8TQ and I believe it still has the original battery. What is the life expectancy and how would you know if the battery is going bad? I left the cabin overhead light ON for an hour and my battery drained to 9V. I think it should have gone low that quick.
Does anyone use a different battery than the OEM? If so, what do you use?

 

just got my battery replaced today. had the stock battery since purchase (october 1999 for 2000 A4). lasted me almost 6 years.
the biggest clue for me was the start... battery just died overnight.. had enough to start a couple of times but after the third day i needed a boost. no warning however.. it just happened

stock audi battery cost $165 CAD... easy enough to replace.. just make sure the dealer charges it for you before you take it home.

B

 

Battery will last 4 or 5 years with care and topping up the cells twice a year with distilled water. PEPBOYs or sears sells replacement batteries.

 

Does Die Hard have an actual replacement?