The Victron Argofet 200-2 is a FET-based battery isolator switch that charges two separate battery banks from a single alternator or charger, with no voltage drop across the unit. It suits marine, vehicle and off-grid systems where independent battery banks need to stay isolated from each other during discharge while sharing one charging source.

Key features of this battery isolator switch

• Continuous current, 200A rating for high-capacity alternators and charging systems.
• FET technology, removes the 0.6V to 0.7V drop found on diode-based isolators, so batteries receive the full charge voltage.
• Dual output, charges two independent battery banks from one input with no cross-discharge between them.
• Low power loss, less heat generated compared with diode isolators.
• Housing, aluminium casing suited to engine bays and confined spaces.
• Compatibility, works with standard alternators and battery chargers, no modification needed to the charging source.

How it works

Diode-based isolators typically drop around 0.6V to 0.7V between the charging source and the battery, which leaves batteries chronically undercharged. The Argofet 200-2 uses MOSFET technology instead, so the voltage at each battery terminal matches the alternator or charger output directly. Current flows freely to each bank during charging while reverse current between the two banks is blocked, so a discharged starter battery cannot drain the leisure bank, or vice versa.

It's a passive device. No external control wiring is needed in most standard installations, and it responds automatically to charging voltage.

Applications

• Marine vessels with separate starter and domestic battery banks charged from one alternator.
• Motorhomes and campervans needing isolation between the starter battery and habitation bank.
• Off-grid vehicles and 4x4 expedition builds with dual battery setups.
• Commercial vehicles keeping auxiliary equipment batteries independent from the engine start battery.

What's in the box

• 1 x Victron Argofet 200-2 FET battery isolator

Installation notes

Fit this with a qualified electrician or experienced marine or vehicle electrical installer. Connections must be rated for 200A continuous current, with fusing on the input cable as close to the source as practicable. Mount in a ventilated location away from water ingress; airflow around the unit is still recommended even though heat output is lower than a diode isolator. Check compatibility with your alternator output and battery chemistry before fitting.