Get a High-Output alternator, upgrade your wires in your engine bay. If you have 2 runs of 0/1 AWG going back, get 3 runs of 0/1 AWG for your Big 3. And remember, it's always better to have a bigger ground than power wire in a DC Current system. Get more batteries to run in line, and make sure to get a battery isolator so your front battery has less chance of discharging. You can keep the cap if you want, but odds are it's not helping as much as you think it does.