2005 Boxster: Battery dead every time!

[stalkey]

Hi,

I have a 05 boxster. I dont drive it and keep it in parking garage at

work and I start it up every day and every time I need to get it

jupmed, the battery is dead. ive gone through three new batteries. Its

at the dealership now and they cant figure it out. Something unknown

is draining the battery. Does anyone else have this problem? Thanks.

[Loren]

:welcome:

This sort of thing has been covered here a few times.

The need to put an amp meter in series with the battery. Then remove a fuse at a time until they find the circuit with the drain.

Once they find the circuit they need to trace down the cause. Many times it is a 3rd party device that is causing the drain.

[JeTexas]

Check the alternator. Sometimes they develop a short which will actually drain the battery when off.

[Glyn]

The alternator has diode packs - a diode only allows current in one direction. If a diode pack breaks down power will be routed to the alternator in the opposite direction which will then try to turn like an electric motor, however it cant because of the drive belt, this will drain the battery very quickly.

Put a clamp meter over the positive cable with everything turned off and the vehicle left for at least 20 minutes to ensure all components have ceased to draw power and read the drain in milivolts, over 40 and you have a problem.

Pull the fuses one at a time and see which circuit is drawing the power