Battery draining whilst parked

[londoner06]

2000 Carrera, cabriolet, tiptronic

 

here's the summary of my situation so far:

 

• 'check engine light' came on, took car to dealer
• code reader indicated that the 'camshaft adjuster,? needed to be replaced, $2,900 including the 85 k service items
• drove the car home, next day battery totally drained. Used trickle charger over the weekend in order to take back to the dealer
• new battery installed, then the generator started overcharging, the battery needle hitting 15 when NOT idling
• was told to drive it a couple of days to see if the computer would notice the new battery, instead the 'check engine' came BACK!
• dealer now plans to install a new generator/alternator on Monday..., that'll be another $1,000
• TODAY battery totally drained AGAIN, when I plugged the car to the trickle charger the lights started flickering and there was a buzzing noise from the trunk hood next to the spoiler, I don't know what resides there
• now car will have to be towed to Porsche to see if they can figure out why the battery keeps draining. I'm NOT convinced that I need a new generator/alternator.

 

Obviously I'm at wit's end, if ANYBODY has any theories or is familiar with this situation I would love to hear from you!

 

Alex

[Loren]

The need to put an amp meter on the battery and measure the draw with the car parked (everything off). It should be 40-60 ma.

If it is not then they need to pull a fuse on each circuit until they find the circuit with the draw. When they do they need to look at what is on that circuit.

Most common is a 3rd party radio/amp that never turns off. But of course it could be a short of another component.

 

Any 3rd party equipment on the car?

[londoner06]

Thanks Loren. I hope that you're doing well!

 

There is no 3rd party equipment that I know of. The weirdest thing is that buzzing sound from the trunk hood next to the spoiler. The car also allegedly has a broken convertible top alarm sensor that causes the alarm to go off by itself occasionally when the car is parked. That was another $1,000 so I decided to live with the occasional alarm.

 

Thank YOU for your advise Loren! I will pass it along.

 

Alex

[Ahsai]

By trunk I assume you meant the rear engine lid. It's possible the diodes or the regualtor in your alternator fail, which causes the large parasitic drain and higher than normal 15v output.

 

The shop should not have let you keep driving the car with 15v charging voltage. It's dangerous as it overcharges the battery and boils the electrolyte.

[londoner06]

Thank You Ahsai. I will have the car towed to Porsche and will pass along your suggestion.

[DBJoe996]

A simple test of what Ahsai said is to leave the car overnight so it is stone cold, then place you hand on alternator.  If it is warm/hot, the diodes on the voltage regulator on the back of the alternator are fried.  You can replace just the voltage regulator.