Shawn,
You asked for some opinions…Here are mine.
The best isolation system on the market is made by Hellroaring.
http://www.hellroaring.com It has battery charge sensing, and priority charging to the “engine start” battery that the other systems do not have. When you run a really big stereo system, this becomes important. Your system is huge! If you really use it turned up, you are drawing over 350 amps for the stereo alone. That is more amps than most starters use to start our boats – for just a second of cranking. No wonder you batteries don’t seem to last long.
Do not expect an isolator to make a difference in the time you can run your stereo. The best you can hope for is an efficient isolator that sends as much from the alternator to the batteries as possible. Most likely an isolator will allow less power to go the batteries than a “Perko” switch. Excellent isolators like the Hellroaring only reduce the charging by a tiny amount. Inexpensive diode type isolators reduce charging current and voltage by much more.
If you really want to use your stereo for more time, cranked up, you need to have more power available. You could either use more batteries, or upgrade your charging system, or both. A guy I know has a deck boat with a real monster stereo system – well over 10,000 watts. He sits on a beach all day and cranks the thing. He powers it with TWENTY 6 volt golf cart batteries. He pulls his boat out in the evening, and puts it on an industrial charger all night, so it is fully charged for the next day. The stereo system is not connected to his “boat” electrical system at all.
My stereo system is about 2000 watts RMS. I run three Optima batteries – 2 deep cycle for the stereo, and 1 starting for the boat. My stock alternator was only 51 amps. Turned up, my stereo alone draws over 150 amps – measured with a digital current meter. Because I boat where I cannot “plug in” my boat at night, I needed a charging system that could keep up with the draw. I installed two 105 amp alternators on my boat. With the boat running, the alternators keep the batteries fully charged, and with the Hellroaring isolator, I can run the stereo batteries completely flat (engine not running), and still have a fully charged battery to start the engine. No switches, nothing to think about, it just works.
I hope this helps.
Geoff