My amps are going into protect from low voltage. How can I fix this?

I have a 220 amp alternator that runs at 14.2 volts, Big three in 0 guage, 40 farad cap, and an Optima Yellow top. My voltage drops down to 9.6 at the amps and they shut off. I only have about 1700 watts RMS so I don't get it. And for those that are gonna say ditch the cap. I tried it that way. Shut off quicker.