Hi guys,
I have a 2004 C5. A few weeks ago the battery, after an overnight stop, was fully depleted. Having connected a charger, this charger refused to start charging as there was not a drop of residual power left in the battery. I overcame the problem by paralleling the car's battery with a fully-charged spare battery and then connecting the charger. As soon as the car's battery had restored some level of voltage, the charger could be connected normally and after an hour had fully re-charged the battery. I was, however, stunned why this had happened !!

Today I drove the car for about 100 miles, parked it and 6 hours later... again a fully depleted battery. This time I was able to start the car by jumping a cable to the car of a colleague. Driving back the battery re-charged normally
However I noticed that, with the radio switched off, I could hear statics coming from the speakers. The radio worked normally when turned on, albeit with a minor level of statics. I drove home with the radio switched off. Once at home, I turned the radion on but heard a loud bang somewhere behind the instrument panel, like a stone being thrown against the window.
Turning the ignition off and having taken the key out of the ignition, I heard a whining sound coming from behind the instrument panel, as well as the statics still coming from the speakers. I then decided to disconnect the battery (the black lead). Inside the car I could smell a very light smell of electrical fire.
I assume that there is some form of electrical shortage somewhere in the audio-system.
Is that also your feeling ? Is there a fuse (and where ?) so that I can disconnect the audio-system in total so as to take the car to the dealer ?
Any help is greatly appreciated !! Happy New Year to all of you !!
Alex