Boat Battery Isolator or VSR? | Boat Wiring - Easy to An isolator is much easier to install on an inboard engine. The alternator wiring is much easier to access. As for the confusion in terminology, BEP Marine calls their device a VSR. Blue Seas call the device an ACR. Both do the same thing and connect the same way. Hope this helps Battery Management Wiring Schematics for Typical The following basic wiring diagrams show how batteries, battery switches, and Automatic Charging Relays are wired together from a simple single battery / single engine configuration to a two engine, one generator, and four battery bank system.