car battery problem

Hi there, I have a question regarding my car. Now here's a little prelude, my car is currently under construction (91 Grand Am) as in overhaul. Everything electric was ripped out because of the plethora of problems I've been having with it. So I tore out the ECU and all that just so I could rewire it, do custom lighting/fiberglassing, and put in my 4x 15" subs and 3x 10" subs without running into anymore constant fixes (the wiring was literally duct taped together so I solder/heatshrink it. I have done the big 3 already BUT here's what it boils down to. Since my car has not been running for a while, I always listen to the car radio when I work on it. I got the stereo system wired, windshield wipers, and lights almost finished. But the only thing connected to the battery + is the subwoofer amps and the radio. Now the sub amps don't ever get turned on as a good 35-40 amp draw will discharge the battery quickly. But I do turn on the radio when I work on the car. To keep it charged I run a 1.5 amp trickle charger to the battery. Yet the real issue steps into play. The battery I have is less than 5 months old and now when I connect the charger it says the battery is charged. I plug in my radio and boom it doesn't work. There is enough water in the battery so I'm thinking that because I've been running on a trickle charger (12v) that the voltage may have gone too low for anything electrical to work. I have tried disconnecting all leads and grounds and nothing has worked. It's not my radio either and my lights don't turn on. So my question is am I right or if not tell me what the issue is or can I just fix it by running it on a regular 14.4v alt for a while to bring the voltage up? I have searched long and far so I've finally come here. Thanks in advance! :D -Josh

have the battery load tested before going any further. since the battery is only 5 months old you should be able to get a new battery without being prorated if no good.This information is provided only as a reference.

All circuits should be verified with a digital multi-meter prior to making any connections.