964 Car Alarm & Battery

[mcgc0]

A bit of a problem on my hands; Only recently, I was awoken in the middle of the night by the car alarm (roughly 20 secs of a weak horn blasting off - a short break then repeated once again and that's it). Not a big deal I thought, as it's locked in the garage and the air temp during the day was over 30oC, so put it down to weather sensitivity etc.

Now, with the car unused for a couple of days, I then found the whole thing electrically dead - no juice at all. Re-charged the (2-year old) Bosh battery then locked/alarmed the car. Flip me - a couple of days later, no juice again! I have now charged up again, but this afternoon parked in the street the alarm repeated the cycle again... I will leave in the garage unlocked/unalaramed tonight for a couple of days to see if the battery drains again.

Beyond this I have no idea. Done the voltmeter check with engine idling, and then again with headlights full beam and all fine at 13.7v, so hopefully alternator is ok (might perform same check again with all electrical items on).

Only other security feature is a Clifford Eagle II mobiliser, but that I believe is not the problem (unless anyone can correct me).

Any ideas or similar stories? Does the Porsche car alarm play up a bit?

Marcus

 

[mcgc0]

Can report that it isn't the car alarm, as with the doors unlocked and unarmed the battery was dead again after a couple of more days. Thinking more now that simply the battery is duff. I also remember from a friend that the car alarm sounding off ad-hoc in his car was the duff battery or supply was weak - a change of battery fixed his problem. An often topic discussed on other forums with many suggestions and opinions. Probably the quickest (and cheapest) elimination is to replace the battery and take it from there. Know a reasonably priced Bosch (or matching) battery seller? I believe the specs should be: - 75Ah capacity - 800 EN cold cranking Are these minimum? A case of the more the better?