Victron Argofet 200-2 200A FET battery isolator for 2 batteries

Victron Argofet 200-2 Two batteries 200A

Similar to isolation diodes, FET isolators enable the simultaneous charging of two or more batteries by an alternator or through a charger connection without connecting the batteries to each other. A discharge of the onboard electrical system battery does not lead to the simultaneous discharge of the starter battery.

Unlike isolation diodes, FET isolators have virtually no voltage loss. The voltage drop is less than 0.02 volts at low currents and merely 0.1 volts at higher currents.

With ARGO FET battery isolation, no voltage increase is required. However, one should pay attention to short cable lengths and sufficient cross-sections.

An example:
A 100 A current with a cable length of 10 m and a 50 mm2 cable cross-section has a voltage loss of 0.26 volts. With 5 m of cable at 10 mm2, a 50 A current causes a voltage loss of 0.35 volts!

Alternator starting excitation
Some alternator types require direct current at the B+ terminal for starting excitation. On the one hand, there is a direct cable connection due to the connection between the battery and the alternator. On the other hand, however, the isolation diode prevents reverse current flow, so the alternator does not start. The new Argofet battery isolation has a special current-limited connection for starting excitation when the alternator is started.