The Victron Argofet 200-3 is a FET-based battery isolator that charges three separate battery banks from a single alternator or charger, with no voltage drop penalty. It suits marine, vehicle and off-grid systems where independent battery banks need to stay isolated from each other while sharing one charge source.

Key features

• Three isolated outputs, charges three independent battery banks from a single input, with full isolation between banks so a fault or discharge on one cannot affect the others.
• FET technology, MOSFET switching removes the 0.6V to 0.7V drop found in diode isolators, so batteries receive the full charge voltage.
• 200A rating, continuous current rating suited to high-capacity alternators and multi-bank systems.
• Alternator voltage sensing, compensates the alternator output so charge levels stay correct across all banks.
• Aluminium body, includes an integrated heat sink for passive cooling, no fan required.
• 12V and 24V compatible, weighs 1.37 kg, straightforward to mount in an engine bay, battery compartment or distribution panel.

How it works

Diode-based isolators lose around 0.6V to 0.7V on every charge path, so batteries never quite reach full charge voltage over time. The Argofet 200-3 removes that drop with MOSFET switching, so each bank sees the same voltage the alternator or charger produces. Each of the three outputs stays isolated from the others: if one bank faults or discharges deeply, it cannot pull down voltage on the rest. That separation matters on a vessel or commercial vehicle where a starter battery has to stay protected from domestic or auxiliary loads.

An alternator voltage sense connection lets the regulator see actual battery voltage rather than the voltage at the alternator terminal, correcting for cable resistance on long runs.

Applications

Used on marine vessels needing separate starter, domestic and bow-thruster banks from one alternator; on HGVs, coaches and commercial vehicles with multiple auxiliary banks alongside a starter battery; in motorhomes and campervans keeping a leisure battery isolated from the vehicle starter; and in off-grid installations with one charge source feeding several battery banks.

Installation notes

Fit by a qualified electrician or marine electrical engineer familiar with high-current DC systems. Mount in a well-ventilated location on a surface able to support the unit and its cable connections. Size cabling for 200A continuous current and fuse both input and outputs. Connect the sense wire to the alternator's sense terminal per Victron's wiring documentation, and avoid enclosed spaces with no airflow around the heat sink.

What's in the box

• 1 x Victron Argofet 200-3 FET battery isolator