Dead battery - Is the alternator bad?

[dghii]

Originally Posted by Ian c

Ahhhh ....
The good old "diagnose with your wallet" theory

No. A 3 time Boxster owner who had the EXACT same problem 3 months ago and who fixed it after diagnosing the problem.

You want to verify you have a bad regulator? Get an oscilloscope and look at the output of your alternator. You'll see that you're missing (at least) one of your diodes.

[Ian c]

Ive had a bad diode draining the battery , also a bad connection on the alternator , a bad battery connection , bad radio , bad ground , bad ignition switch , bad alarm , bad immobiliser , bad door switch etc etc etc .

You could well be correct , you could well be wrong .
You could scope it to test , or you could meter it .

I too had the EXACT thing happening within the last 3 months on my boxster ....
It was the ignition switch ...

I'm used to diagnosing before ordering parts and scheduling labour ....
It's what I do for a living , and have a huge amount of test gear at my disposal ( each Instrument tech working for me carries about 20Ks worth in their toolkit)
If I did it by guesswork and throwing money at it , no matter what past experience tells me , I'd be claiming unemployment

This is me diagnosing using experience .
Just a pity the guy had allready been to the main dealer , then 2 specialist that diagnosed with his wallet first ....
http://www.volkszone.com/VZi/showthread.php?t=850130