power problem

ok guys need some advice. I have a 2000 cavalier and this is what I have in it: 1200wt JBL amp, 400wt Crossfire amp, Air ride compressor drawing 17amps, PS2, power converter, and a 7" screen for the PS2 (obviously) now this is my issue every thing runs and works except my monitor. I shouldn't say that when I'm parked (car running at idle) watching a movie or whatever the screen works good for about 5 min then it gets a bunch of lines and goes blank; untill I put my foot on the accelerator and raise the RPMs then it pops back on clear as a bell. Now obviously a power problem. Now I do have an optima yellow top up front, no second battery, and had my alternator rebuilt from 120 amps to 180amps. I imediatly thought I just need to put in a 2nd battery, but then by friend pulls up in the exact same car with a $30 wallmart battery and factory 120amp alt. and he's running 2 Crossfire 2000D amps and a 23amp air ride compressor. A HELL OF ALOT MORE DRAW THAN WHAT I HAVE. And he has no problem at all. So I'm a bit confused on what to do. Like I said my monitor is the only thing that malfunctions and thats drawing the least power I don't get it. Now when I got my car out of storage after sitting 6 months (I live in Wisconsin) the battery was dead but I just got a jump and let the alternator charge the battery I never trickle charged it and I know the alternator wont "fully" charge a battery it more or less charges to a point then maintains, could that be my problem, that I never had a fresh battery to start this show season with? Would it help to pull it and give it a full charge then see what happens? Cause with my boy have 4000wts knockin in his car on a cheap battery and doing fine me getting a 2nd doesn't sound right at all. Thanks for taking the time to read this and for any advice...go custom or go home!!

Sorry bout that concerning the yellow top, guess it shows you how knowledgable I am didn't mean to affend anyone. But anyway I got my Alternator tested and battery today, both are fine however the voltage from the alternator to the battery read 12.1 at idle (600 rpms), and 14.8 at 1000rps (give or take). I thought at idle it should still clear 14 maybe I'm wrong there as well, the shop that rebuilt my alternator said that with high output alternators they wont start working for you until the rpms are up. What do you guys think about that? Truth or BS? I then asked what I could do to solve my "idle" power problem they all looked at me like deer starring into headlights and nothing solid to say. So after testing I'm still stuck with my problem, any other thoughts guys? Thanks a lot again!!go custom or go home!!

ok got it figured out I'm adding another battery. DYohn, I need it at idle for show purposes, at a show I like to have a video playing or play a video game and ofcourse play with the air ride, and I usually always have the car running when doing so. Now it isn't for the whole show maybe an hour at a time here and there and for maybe a total of 4hrs through out the day. Thanks alot again I really apreciate it!!go custom or go home!!