cutting wires.......
Dude, you got to solve the problem, not create another one. If your trying to run a 5000 watt system, then you'll need to carry a portable generator!
Boat charging systems and 12 volt batteries are not meant to out play the next guy down the street.
But, a way you can help yourself out is to install a battery isolation switch. That way, when the boat is off, on a sand bar or something, you can switch to battery #2 or which ever you have your stereo connected to, then play away but remember, the more power you put into the spearkers, the less time you'll have listening to your music. The speakers and amps are 90% of the stereo's system, the actual tuner uses zilch. WHen you go to start the motor back up, switch to #1. Once you start, switch the selector to "ALL".....I would have the stereo system on a direct lead to that dedicated battery and when the boat lanyard is pulled or everything is powered down, you'll still have the music.........
There are marine inverters and hi power systems available but will cost in the thousands to do it right. :cheers: And if your wasting your battery with your music, I hope it's to something good like "Distrubed" or the new "Lincoln Park".........!:rofl: