Victron Argodiode 140A 3-Battery Isolator

The Victron Argodiode 140-3AC charges three banks from one alternator using Schottky diodes, with a built-in compensation diode.

The compensation diode is what distinguishes the AC versions, and it corrects for the voltage the isolator itself loses. Fitted into the alternator's sensing circuit, it makes the regulator see a lower voltage than actually exists, so the alternator raises its output to compensate and the banks receive what they should.

Without that compensation a diode isolator leaves every bank charging around half a volt short. Over years that shortfall is what sulfates a lead-acid bank and costs capacity permanently.

Schottky diodes reduce the loss to around 0.3V at low current and 0.45V at rated output. A hundred and forty amps across three outputs suits a standard alternator, and the FET-based Argofet range avoids the drop entirely if compensation is not practical. Explore more battery isolators and charging relays.

• The compensation diode corrects the isolator's own loss
• It makes the regulator raise the alternator's output
• Without it every bank charges half a volt short
• That shortfall sulfates a bank over years