My cap has two positive terminals and two negative terminals. Put the 4ga from battery to one positive and then the wires to my amps in the other. Do i need to ground both negative terminals or just one or what? Does anyone know?

 

Only one! You can use the other negative as a grounding post for something else, if you want. What kind of cap is it?

 

its a power acoustik. So run one power wire from bat to terminal, then pos terminal to my amps. So I will have a 4 awg and 8 awg wire coming out. So use an 8 and 4 ground out of one slot? So then can I ground my amps to the other terminal on the cap? And just have one ground on my car? Or should I just make three grounds on my car. One from each amp and one from cap?