Overview

The Victron Energy ARG080202000 is an Argo Diode 80-2SC battery isolator for charging two 12V or 24V battery banks from a single alternator while keeping the banks electrically separated. It is rated for 80 A maximum charge current and 80 A maximum alternator current, with M6 stud connections and a 6.3 mm Faston connection for the compensation diode.

This isolator suits boat electrical systems where a starter battery and a house or accessory battery share the same alternator. Both banks can receive charge at the same time, but discharge from the service side will not also drain the starter battery. Schottky diodes keep the voltage drop low, at approximately 0.3 V at low current and approximately 0.45 V at rated output.

Key features

• Charges two battery banks from one alternator while keeping the banks separated from each other.
• Suitable for nominal 12V and 24V battery systems.
• Rated for 80 A maximum charge current and 80 A maximum alternator current.
• Schottky diode design keeps voltage drop to approximately 0.3 V at low current and approximately 0.45 V at rated output.
• Compensation diode connection can be used with alternator voltage sensing to help offset isolator voltage drop.
• M6 stud main terminals support secure high-current DC cable connections.
• Compact housing measures 60 x 120 x 75 mm for installation in tight electrical compartments.
• The 80-2SC model does not include an alternator energize input, so alternators that need B+ excitation should be checked before installation.

Installation and setup

The isolator is installed in the positive charging path between the alternator and the batteries. The alternator positive output connects to the isolator input, and the positive feeds for the two battery banks connect to outputs 1 and 2. The battery negatives should return to a common negative bus.

Before working on the DC system, the battery negative cables should be disconnected. Cable runs should be kept short and sized for the charging current, as voltage drop in long or undersized cable can reduce the charge reaching the batteries. The unit can become hot in service, so it should be mounted only on a non-flammable surface with enough space around it for heat to clear.

Marine use

On a powerboat, sailboat, or fishing boat with a separate engine start bank and house bank, this isolator helps preserve starting reserve while still allowing alternator charging to reach both banks. It is a practical fit for straightforward dual-bank DC systems where the goal is separation rather than battery combining for shared loads.

System protection, battery switching, fusing, and cable sizing should be handled as part of the vessel's overall DC installation. For alternators with external sensing, the compensation connection can help account for the diode voltage drop so the charging system is set up more accurately.