I have a 98 a6 Q 2.8
I just replaced the battery. It did not just die, it acted like it was being drained, so I measured thecurrent drawwith an amp meter.
It is drawing about 0.87-0.91 amps with the car off and doors closed.

Is that normal?

I have not tried to pull fuses to see where the draw is coming from because I don't know what the draw should be.

I also noticed that with the ac on the volt meter reads just over 12.75
If I turn the ac off, it goes to about 13.5

Should there be that much difference?

Could a bad voltage regulator cause the current draw and the swing in voltage?

Thanks.

 

You are drawing too much power when the car is off. There seems to be a parasitic voltage leak, and you are seeing 12.75 volts at the battery when the a/c is on because of your dead battery (probably). The alternator could be weak, but is probably just acting that way because the battery is drained. Start pulling fuses.

Jeff

 

Thanks for the reply Jeff,

It is a new battery.

Could a faulty alternator cause voltage drain?

One more thing..
I tested the drain using the positive lead of the battery. Is that proper?

 

Un-plug your navigation unit and see if the amp draw goes away, those have been known to do that.

 

Mine does not have a navi unit.

 

A faulty alternator is a possible cause, but more than likely it is a trunk light, stereo, or any number of things. You are checking it the correct way. Even with a new battery, if you will see the results you listed above. My old Saab had a trunk & glove compartment light that always stayed on and drained the battery over a couple of days.

 

No Nav huh? Well that sucks LOL.
Yeah the most likely problems are like what Jeffla said, interior lights or some kind of control unit not going to "sleep"

 

Hopefully it is not the alternator. I've never put the car in service mode before. But, there's a first time.....

I'll pull the fuses and see if I can find the culprit.

And,
Navi, yeah that would be very cool!

Thanks for the help.

 

The current draw was coming from the sound system.

Apparently when the battery is removed, reconnecting causes the sound system to turn on.

Turn the radio off and there is only 26mA being drawn.

Great news!!

Thanks for the help.