ProMariner ProIsoCharge 120A 2-Battery Isolator

The ProMariner ProIsoCharge 120 1-2 is a digitally controlled 12V isolator charging two banks from one alternator, rated 120 amps.

This is the two-bank version against the three-bank ProIsoCharge, and bank count is what separates them. Two banks covers the common starting and house arrangement. A boat with a separate accessory or thruster bank needs the 1-3 version rather than adding a second isolator.

Zero-voltage-loss isolation avoids the drop a conventional diode splitter introduces. That drop is around 0.6 volts, and it means the batteries never see the full charging voltage the alternator is producing. Over years it leaves a bank chronically short of a full charge.

The all-digital architecture protects the engine-start battery specifically rather than treating both banks alike. A hundred and twenty amps is the alternator capacity handled, and it should exceed what the alternator actually produces. Explore more battery isolators and charging relays.

• Two banks, against the 1-3 version
• A third bank needs the larger unit, not a second isolator
• Zero voltage loss against a diode splitter's 0.6V
• That drop leaves a bank chronically short