ProMariner 130A Single Alternator 3-Battery Isolator

The ProMariner 130A Single Alternator 3-Battery Isolator lets one alternator charge three separate banks, with gold-plated terminals.

Three banks from one alternator suits a boat carrying starting, house and accessory batteries separately. The isolation is what makes that arrangement work: a heavily discharged accessory bank pulls hard on the alternator without dragging the starting battery down with it.

Keeping the starting battery separate is the whole point, since it is the one that has to work when nothing else does. A bank that shares its charging path with a flat accessory battery finds itself lending current rather than receiving it.

A hundred and thirty amps is the alternator capacity the isolator can handle, and it should exceed what the alternator produces. Gold-plated terminals resist the corrosion that quietly raises resistance in a high-current connection over years. Explore more battery isolators and charging relays.

• Three banks from one alternator
• For starting, house and accessory batteries
• A flat accessory bank otherwise borrows from the starter
• 130A should exceed the alternator's output