Battery electrical mystery

[ZnAlloy]

I measure a current from the battery of my 1991 911 Turbo, when all of the fuses are removed (including those in engine compartment). This current is about 0.5 amp. This is presenting a battery drain problem. When used normally the battery requires a charger about once a week. Has anyone encountered this?

[911pcars]

Originally Posted by ZnAlloy

I measure a current from the battery of my 1991 911 Turbo, when all of the fuses are removed (including those in engine compartment). This current is about 0.5 amp. This is presenting a battery drain problem. When used normally the battery requires a charger about once a week. Has anyone encountered this?

I assume you've connected an ammeter between ground and battery ground cable. Since you removed all the fuses, I might suspect a current drain somewhere in the alternator/charging system. To isolate the alternator, temporarily disconnect the alternator wire at the starter motor, then see if that affects the current draw. Any other non-factory accessories connected to the elec. system?

Until you find the cause, keep a battery maintainer on the battery or disconnect the ground cable. Don't allow the battery to cycle between charge and discharge. It will reduce battery life.

Sherwood

[ZnAlloy]

Thank you for the input. Yes, the ammeter is connected between the ground cable and battery ground post. What you suggest about the alternator seems like a fertile area to explore, since replacement alternators (2) have been installed over the last 2 months.

[ZnAlloy]

And on your question about nonstandard equipment, I believe the answer is that there is none. There is the period radio and amplifier, which seem to be fused properly and part of the original equipment. The alarm/door locking is also part of the original package.