Battery/Power Issues 2000 Jetta

[Infoolio]

For the last 6 months or so I've been having serious battery/power problems with my 2000 Jetta 2.0 (the battery is being drained). It's got about 30K miles, had battery replaced in 2004. Last Nov. I took to VW dealer and paid $140 for them to tell me nothing was wrong. After it died again I took it to a garage and had the battery replaced (warrantied interstate battery, so I was only out ~$40 for labor). Now less than 3 months after that battery was changed, the car is dead again and I'm at the end of my rope dealing with it. When I say dead I mean literally dead - not even power door locks, alarm, etc work (turning the key in the ignition does absolutely nothing).

VAT40 test (at garage) showed that the old battery couldn't sustain heavy loads. Yet electronic test showed 0 drain whatsoever when the car was off. I drive about once a week for 15-20 minutes to get groceries, but not much more since I'm in school and it's more convenient to use other transportation.

Not really a car person, and though I do trust my garage I'd really appreciate any ideas presented so when I take it back in to the garage and they tell me I need new X, Y, Z, I won't be stunned.

Thanks.

[veedubmechanic]

Originally Posted by Infoolio

I drive about once a week for 15-20 minutes to get groceries, but not much more since I'm in school and it's more convenient to use other transportation.

there ya go. Drive your car every day and the battery wont drain down. There is always a constant drain on the battery, max allowable is .03 amps.
The computer systems always drain the battery down, for a normal person who drives there car every day, this is not a problem. But for someone who drives there car once a week it is a problem. Once the battery starts draining down and is not charged the battery lead plates sulfate and the chemical process that allows a battery to charge and give off electricity can not happen properly (aka battery doesnt charge after being disgharged).
You could always just disconnect the neg. battery cable when you dont drive it but then you would have to reset the radio every time yo drive it and the check light may come on.

Suprised the garage wouldnt test the alternator or starter.