Battery Hookup Question

Since I have read that having so many battery's hooked up to be charged by the boats alternator, I am wondering about this idea:

Have 2 AGM battery's wired together but not on any Perko. Have them as stand alone. Keeping the two battery's that I currently have now as starting but keeping the remote wire for the amps connected to the switch on my dash so that I can turn off and on as needed. Then I have my Prosport 12, onboard charger, plug it in each night to recharge the battery's. So the radio will be hooked up to the starting batts and so will the helm as it is now from the factory, just the two Syn 4's will be hooked to stand alone batts. Anyone see a problem with this idea?

I need to know soon as I will be working on the boat again this weekend. David E.M., Tim? Any thoughts?

So you only have to batteries wired in parallel or you have 2 in parallel and another battery or 2 for starting/running the critical systems?

David,

No can do!
The two isolated banks will predictably be at different levels of charge at different times. The RCA ground shield between the source unit and amplifiers will be the sole route for circumventing the isolation. Even though the ground shield is technically 'above ground' (typically 1000 ohms (this represents the least path of resistance for a difference in potential to flow and any difference in voltage will attempt to correct itself. This can result in noise induction and can possibly even cause damage to the preamp drivers.

There are much better solutions in protecting your alternator from a substantial load beyond what it was intended for.

David E.M.