The Victron Argofet 200-3 is a MOSFET-based battery isolator that charges three separate battery banks from a single alternator or charger at up to 200A continuous current, without the voltage drop penalty of a diode isolator.

Key features

• Battery isolator switch for three independent battery banks from one input source, rated at 200A continuous.
• MOSFET technology removes the 0.6V to 0.7V drop typical of diode isolators, so batteries receive the full charge voltage.
• Voltage sensing feeds actual battery voltage back to the alternator regulator, preventing undercharging.
• Aluminium heatsink body dissipates heat with no fan or active cooling.
• Full output isolation stops one battery bank discharging into another when the input source is disconnected.
• Compatible voltages: 12V, 24V and 48V systems. Weight 1.37 kg.

How it works

Diode isolators drop roughly 0.6V to 0.7V on every output, which leaves batteries chronically undercharged unless the regulator is adjusted manually. The Argofet uses MOSFETs in place of diodes, so the drop in conduction is negligible and the full alternator or charger voltage reaches each bank.

A dedicated sensing wire carries true battery voltage back to the alternator regulator, correcting for the difference between alternator output and battery terminal voltage. This keeps charge termination accurate without extra wiring changes elsewhere in the circuit.

Applications

Fits marine vessels with separate starter, domestic and bow thruster banks; motorhomes and campervans isolating a starter battery from leisure batteries; commercial vehicles running auxiliary equipment such as refrigeration or tail lifts; and off-grid setups where one alternator or DC charger feeds multiple banks. Also used as a retrofit replacement where a diode isolator has caused persistent undercharging.

Installation notes

Fit by a qualified electrician familiar with high-current DC systems, mounted on a flat metal surface for heat dissipation. Connect the sensing wire to the alternator regulator per the Victron installation guide, and use cabling and fusing rated for the full 200A load.

What's in the box

• Victron Argofet 200-3 FET battery isolator unit