Originally Posted by wakeboardhead84
I wasn't positive I needed the second battery but from what I have read it's not a good idea to have the amp powered by my 1 cranking battery.
Put a second battery in the machine. Can't go wrong. Wire them parallel.. no big deal and that is typically how the setup goes. The isolation switch will separate the banks when you turn the ignition off or to accessory. You will not be drawing anything from the start battery (while in accessory position) when you do the setup correctly.
When you start the engine, the isolation switch will fail closed thus charging both batteries during operation. When you go to accessory (for the tunes) the isolation switch will fail open and separate the banks. Exactly what you want.
Install two. Done deal and no second guessing when you are on the water.
Move the rear battery up front away from the fuel cell and add a second under the deck on up front. You add 3.5' of cable to the hot and the ground (compared to the original install). No big deal. I did re-cable my machine and started with new cable runs. I also upgraded the alternator and lead cable from it to the starter.