my battery discharges when its below 30 or so(long)

[Nick McCollom]

I dont get it, mycars battery dies every time its
cold. I can usually pop the clutch going down the hill
in front of my house. but today it wouldnt do it. I
cant even jump it. I usually can but right now its
12degrees outside.I let it charge for several minutes
off my grandpas buick and it would try to turn over
two or three times then it would start to click. I
tried the ground on the bat. and the chassis. when I
put it on the chassis the lights got dim. Is this an
indication of a bad gound connection? or is there some
dead cell(s) in my battery? I put a new alternator on
about 3-4 weeks ago, the battery I got last winter.
could my alternator going bad have killed the battery?
In the time frame that this has been going on I've put
on a PS header removed the cat with a test pipe and
the ground back there isnt connected. Is this
important? I've put the alternator on and pulleys(
Ihad the crank pulley on for a while but added a wp
pulley and alternator pulley. I've replaced an amp
with a new amp for the stereo and added a stinger
distribution block for my two amps. could something be
draing it here? I've pulled the fuse on it today too.
what can I do to narrow this down? Thanks for reading
my long rambling but I'm quite confused right now.
           Thanks again
              Nick McCollom 93 nx2000 with some of the
weirdest problems ever( And ask some of the people who
know my car how hard it is to make to the top of Nicks
weird problem list)