Dual battery isolators?


Hi PYS - As a new power boater, I've been loving your YouTube videos. Both the long form videos and the short Ask PYS series. Incredibly helpful. My question is, in doing an electrical audit of my new boat (2000 Regal 4160) I noticed that I have 2 battery isolators. Is this recommended? Is there a better way to do this?

One isolator that the 2 alternators are connected to, and another one that the inverter/charger is connected to, via fuse, then directly connected to the alternator isolator, presumably to pass on the charge to the 2 starting batteries?  I've attached a photo that I annotated to hopefully describe what's going on.  Any recommendations for improvement wouldbe greatly appreciated! - Chris


Hi Chris, Thanks for the feedback, and we are glad PYS content is resonating with you. The described, and pictured, arrangement is a bit unorthodox. The battery cable that is stacked on the inverter side of the fuse by-passes the fuse, so it begs the question as whether there is OCP for the inverter going to that battery bank. Further the output to the isolators is peripheral since battery voltage to those batteries is ‘unsensed’ since the isolator blocks voltage in the opposite direction.  - Jeff