eero181

My 2005 A6 battery keeps draining. I have had this car for almost 10 months now and last month or so it keeps draining battery. At first the problem seemed to be in central locking, but if I started to use the key to lock the doors it started to drain battery again. After that I tried to leave doors unlocked overnight and it helps. If I open a door and after that not locking and unlocking doors again, the battery will drain again. Also noticed that if I leave my wipers in auto position, it will also drain battery. What can be the problem?

Ps! Sorry for my bad english, it is not my native language.

raj99

@eero181 sounds like a parasitic draw. Leverage the SEARCH function and you'll find all kinds of tests you can do, but it can be far more than the locks. Here's one to get you started:
unknown source draining battery - AudiWorld Forums

Sallad

You can also check odd things, like the trunk light not turning off, or glovebox light. Sometimes the little switch can get stuck and not turn off the light.

The old school way to trace it down, would be hook up a multimeter, set to Amps. Then start pulling fuses one by one. Once you see a large change in the readings on the meter, this will tell you what circuit to start looking at.

audisickness

I recently had a battery drain issue and the culprit turned out to be the XM Radio module in the trunk. By passed the module and haven't had a drained battery since.

FONDRIEST12

I have the same issue with my 06 A8, if I keep all the doors unlocked, the battery is fine. If I lock the doors overnight, within a week or two the battery just dies and the car won’t start. I’ve been keeping the car unlocked at home and only lock it when I go out and it’s been fine for the past 8 months. Recently I’ve had to drive the car more and have been needing to lock it overnight and within a couple of weeks, The car suddenly wouldn’t start.