I like how your complain about dimming lights and everything, then you finally come out and tell us that you have a crap battery, leaking at that. 500ca is not much now and days as well. You haven't done the big three upgrades.
No wonder your lights are dimming. I have a Red Top Optima, Upgraded Grounds, a 200watt RMS Class D mono Amp pushing a 12, and a 40x4 rms EQ amp pushing 6 speakers, and at night with fogs and headlights on, my fans can kick on and my lights will not dim while listening to music. And the biggest part, I only have a 90 amp Alternator.
By the way, you can overcharge a battery btw. Having the proper equipment, done right, you shouldn't have charging issues.