Your gonna need a resistor or test light to charge it. And it must be wired in parallel as close to your amp as possible. Here: http://www.bcae1.com/ no. 46 on the right. It tells you how to charge and discharge it towards the bottom of the page.
I cant believe you of all people are asking me this:eyebrow: . If you have an already bad electrical system all they do is make it worse not better. Otherwise they dont do shit and you oughta know that. Allow me to quote somebody "ANYBODY come show me how one of these pieces of junk can actually help the power demands of a 12v system and i promise to go to IRAQ and stand in the center of Baghdad and curse Allah..............RC".