Electrical Drain

[CTScott]

Originally Posted by birdman

The weird thing is that my first battery lasted 16k miles while the second lasted 3 weeks. What ever it was that started malfunctioning started well after I bought the car.
The dealer says they have done all they can and cant find the cause of the problem. Could it be a failure of the diode bridge or voltage regulator in the alternator that causes it to intermitantly stop charging?

I think the key is to first figure out if the issue is lack of charging or excessive "off" current draw. The charging one can easily be checked out by measuring the battery voltage while the car is running. If it is greater than the voltage when the car is off (and is fairly steady {i.e. not bouncing from 12 to 15 volts}) then your charging side is probably fine.