New Alt New Battery 2000 740i

[FABOCH]

I am a N00bie. hello all, I owna 2000 740i sport. 108 k miles on it. I recently had a major issue. My car ran like a champ until 1 night I started driving down the street and my dashboard lights lit up like a xmas tree. My tranny went to trans fail safe mode. I knew I had something going on. the next morning I went to Pep boys bought a New battery. I hooked it up and then the errors were gone and my tranny back to normal...1 prob...battery light remained lit
I took to German Tech in Thousand Oaks, ca Mirek told me that the prob was the alternator. :mad:
$800.00 later:thumbdwn:.....im up and running:thumbup:
Now my prob is Why is my battery going Dead??
i unplugged my Jl Audio System<-------why my alt went bad...my dumb ass didnt use a capicitor like I was told
So why is my New battery going dead?
Dome lights are not on I also dont lock my door so the alarm doesnt suck up the juice.
Any help thnx:tsk:
FABIAN

[FABOCH]

:):)..WELL THANK YO GUYS FOR THE QUICK REPLIES......:tsk:
i FIGURED IT OUT, after I installed the new battery the neg terminal - even though it was tighten- Never had a good ground.......It wasnt draining...it was just not secure around the Neg nipple good enough........I hammered a nail inbetween the nipple and the neg cable clasp.......SOB tight now and no more empty start-ups