Stereo help
 

I bought this boat a few years ago and never had a reason to investigate the stereo system. The other day curiosity got the best of me and I pulled the sub enclosure out and discovered I have a second battery and lots of other stuff I didn't even know about. I understand most of it (I am not a stereo guru) but the 200 amp isolators have me stumped. Does anyone know why there would be 2 of them? Also, I know both batteries should be charging when the ignition is on, but if hooked up to a battery charger, only the battery I have access to in the bow will get charged, right? Thats pretty much the point of the isolator I think.

Disregard the wiring mess...maybe someday I will clean that up.