Originally Posted by VerdiRiverRat
So I was just talking to a friend and he suggested that I consider getting a deep cycle battery and just run my stereo through that. And in doing this I'll have to rewire it and that may inadvertently correct these other issues. I'm always nervous about running my stereo with the engine off anyway so I think this would alleviate that anxiety of dying in the middle of the water. Any thoughts or suggestions there?
Regardless of the type of battery, the wiring needs to be corrected. Also, that new deep cycle battery will need to be charged and running it all the way down isn't good for the electronics connected to it. You can do that, but be prepared to upgrade some other things.
If you do add a battery, it can be set up so the audio system and battery are totally isolated from the rest of the boat's wiring. The main thing to remember is how long that battery will last without being charged. They have a reserve capacity spec- how you use the stereo will obviously affect the reserve, but you should get a few hours if you don't crank it too loud.
If it goes totally dead, just remember that your alternator will hate you if you try to charge a battery that's stone dead.