NightBlue4.2

My A6 was completely dead yesterday morning. Could not even open the glovebox! I have advanced key so tried to start the car with the key in the ignition. It did not make any difference but the key became locked in the ignition switch and could not be removed.
Fortunately I remembered how to open the glovebox with a screwdriver so I was able to take out the manual and find out how to open the trunk and access the battery.
Keeping in mind my key was locked in the ignition I had to use the plastic key to open the trunk.
I boosted the battery and everything started up. Battery level was 10-20% but came back very quickly to 100%.
Question
1) I understood that the car had a system preventing total battery depletion??
2) The only thing different about this situation was that I was listening to the CD when I shut the car down the previous day. Normally I would have had the radio on.
Does anyone have any suggestions as to why this might have happened?

jefman

I'd talk to the service dept, let them check out if you are drawing xtra current. Maybe the cd player is not shutting down.

NightBlue4.2

Thanks. Unfortunately the serviceman is 4 hours away. I will have it checked next time I am near. Like you I suspect the CD stayed on.

Der Kimbo

And had it been locked or unlocked in that time frame?

NightBlue4.2

The car had been idle for 20 hours in the garage and left in an unlocked position. Now that you mention it the two rear doors were locked in the morning when I found it with the dead battery.

Der Kimbo

I've heard of cars going dead after a few days when left unlocked but not that short of a period. When you lock the car it starts the timer to power the systems down (36 hours), but if you leave it unlocked this does not happen. I highly doubt it was the cd player as the audio system will only operate for 15mis w/o the key in the ignition.

seehack

Does the car power down when left in unlocked?

I parked my car for 4 days in the garage locked before Xmas and it starts OK on the 5th day. Today I checked the battery after again leaving 4 days in the garage unlocked this time and its says 100%.

Since mine is OK after 4 days, most likely NightBlue may have some leakage somewhere or a defective battery.

AsKmE

Because that is currently the only device that is not connected to the battery energy management system.

gi jim

had you seen the battery warning light flash when you were driving. Could have a current leak.

NightBlue4.2

The battery warning light was not flashing. No indication there was anything wrong. I suspect that something was left "on" like a light but that was not the case. Car has been fine since.