Car Battery / Alternator Question

[WeakestLink]

I have a 2000 Audi A4 that is driven about 2 miles per day (1 mile in the morning and 1 in the evening). Is that enough to keep the car battery charged? A few weeks ago, I drove it for 20 miles or so to keep the battery charged. Then yesterday, the car wouldn't start (radio/lights didn't work). After jumping the car and driving it around for 20-30 minutes, I still had a problem starting it this morning but it eventually did. So the questions are:

1. Do you have to drive a certain time/distance to keep the battery charged?

2. If the alternator was bad, shouldn't it not have started this morning?

3. If it's the battery, can the battery go bad in 3 years and 1 month? (50k miles on the car)

Thanks.

 

[Lud]

1. Yes, because it uses power to start the car and then recharges from the alternator. The alternator only runs when the engine is running obviously. 1 mile of driving per start is probably pushing it, but it depends on the car. The occasional longer drive to help keep the battery charged is a good idea.

2. Alternators aren't binary. They can put out less power as they begin to fail.

3. Yes. In fact that is probably the most likely. It may be covered under warranty though.. not sure what Audi's warranty is like.

 

[WeakestLink]

Thanks Lud. It turns out it was the battery. I called AAA to have it jumped and found out they offer a new service where they actually install the battery on site. It cost about the same as going to Sears so it was an easy choice. As for warranty, Murphy's Law dictated that my battery should die 2 months after my warranty expired. Thanks again.