Hey ...

Last Saturday evening the battery in my 99 A4 (130K miles) was dead. (Remote keyless would hardly work and interior cabin lights extremely dim.) This is odd because I had just driven to and from work on Friday and nothing was left ON in the interior.

I got the voltmeter out and tested the battery. It came in at 12 volts (sorry, didn't check amp). So, I jump started it and took another reading while it was running. Got 14.4 v at 20 amps. Since I figured it just might be a weak battery, I decided to take her for a spin and tried to produce a heavy load so the alternator would create a nice charge.

For some strange reason, my valentine one (plugged into the cigarette lighter) kept resetting itself. I was able to consistently reproduce the reset by accellerating very hard and pushing on my high beams. The heavy load on the engine combined with the draw of the high beams would always make the V1 reset.

When I got home from my hour long drive, I shut the car off and the interior lights immediately went dim (as if the battery received no charged at all) and when I tried to start the car again, I couldn't. The battery was also back to 12 V.

Any ideas on where I should look? Does this sound like an alternator going bad? (even though I think I had it replaced at 100K miles). Maybe a dead battery (even though I think I replaced it less than a year ago). Is there a short somewhere in the system? Something else?

Thanks in advance for all the assistance.

Best regards,
Brad

 

Sounds like a bad battery to me. If you have a battery charger, try giving the battery some overnight time on that, and see if it holds a charge for a few days. You can also check the water/acid level if you have a battery acid checker. However, if you just bought the battery a year ago, I'd imagine it's still got a warranty? If the battery doesn't hold a charge, and it's under warranty, I'd just get a new battery.
Since this seems to have happened all of a sudden, and no lights were left on, I would doubt you developed an electrical short. I've seen many batteries go bad for no reason.
And it sounds like your alternator is working fine. When the car is running it should be right around that voltage. Sounds like the battery just isn't holding a charge anymore.

 

happened to my car too about 6 months back. one morning on the way back home from a road trip i had to get it jumped from my friend's car. we drove for about 4 hours straight, and i nearly couldn't start it again when we stopped for gas. keep in mind i had the car off for only about 4 minutes. the battery just wasn't holding charge anymore. replaced the battery when i got back home, and it's been fine since.