Dead Battery, 92 e32 735i after 4 days?

I got in my car today; after it sat in the garage for 4 days; but the battery was nearly dead.
No lights were left on; but the key was in the ignition, but not on. '
I put a charger on and let it charge up -- so far so good, while it was charging up, if I turned the key to the 'on' position, the srs & antilock lights blinked;
Once charged up & started the airbag light remained flashing. I reset the error & it has not flashed again.
Questions: 1) can a low battery condition set off the srs warning system? 2) Any ideas on where to look for the drain? 4 days seems "quick", doesn't it? 3) What about those batteries that have a "switch" to enable an "emergency backup battery"? or something like: http://www.griotsgarage.com/catalog.jsp?&SKU6740
or maybe an optima battery? (the current battery is less than a few months old)
Thanks for your thoughts.
-josh
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Yes, and quite a lot more - transmission program for example.

Yep.
First you have to find out if the battery is leaking internally (new battery) or externally (fix it).
Use an ammeter to determine if there is discharge after about 10mins after switch off, and then pull fuses until you isolate it. There are lots of possibilities - stuck on electric fan, locking, windows, charging circuit for computer and radio back up batteries etc. etc.
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Thanks.. More info..
The heater fan switch did nothing -- It wouldn't come on at all -- then I hit the "recirc" button in kind of a spastic "I wonder if I can get it to come on at all" -- that got the fan going; and all appeared normal.
The clock was off (4am vs. 2:30pm) but the date & e verything else (radio) were fine.
Will check the ammeter & fuses....
Thanks -josh
On Sat, 4 Feb 2006 01:36:47 +0000 (UTC), "R. Mark Clayton"

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