battery drain

I have a '97 C5 Corvette. Last spring I installed a stereo with no problems. I ran the car all summer with out any charging issues or the battery going dead. Here is the list of what I have: Rockford Fosgate deck 4 Infinity Kappa Perfect Series 6.1's (2 in front, 2 in rear) 1 JL Audio 10W7 1 JL 500 x 1 amp (powering the sub) 1 JL 300 x 4 amp (powering the kappa perfects) 1 Tsunami X15HCAP-20 capacitor (20 farad) This spring I go to start my car and the battery is dead. I charged the battery and thought nothing of it. I took it for a 2 hour drive the other day and never shut the car off. I got home, turned the car off, started it again with no problems. Two days later I go to drive the car again. The battery is dead. I charged the battery again and got out my fluke for some diagnostics. First thing I did was check out the alternator, which is working fine. Without the power wire (for cap) hooked up I was drawing 87 milliamps which I believe is acceptable (maybe a little high). With the power wire hooked up I was drawing .3 amps. So this lead me to believe that the cap was the problem, but why did the battery go dead so soon? Do you think the battery just went bad over the winter?

If you didn't have a battery tender on your battery keeping it charged all winter it doesn't take a rocket scientist to tell you your going to kill your battery. You have to keep automotive batteries, or any battery for that matter charged or else it will eventually die and gain a memory. Pick up a new battery and a battery tender for next time you store it, you'll be fine. Now, you say you tested the current draw with the cap connected and it was 300 milli amps, but with the cap bypassed your getting 87 milli amps? If thats the case, it sounds like the dielectric is breaking down causing more current draw, and less storage, if you down want to get a higher output alternator, I would recommend finding the biggest spiral cell battery you can fit in the car at least.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.