Victron Argofet 100-3 100A FET battery isolator for 3 batteries

Victron Argofet 100-3 Three batteries 100A

Similar to diode isolators, FET isolators allow two or more batteries to be charged simultaneously via a generator or charger connection without interconnecting the batteries. A discharge of the onboard battery does not simultaneously discharge the starter battery.

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

With ARGO FET battery isolation, no voltage increase is required. However, you should ensure short cable lengths and sufficient cross-sections.

An example:
A 100 A current for a 10 m long cable with a 50 mm² cross-section results in a voltage drop of 0.26 volts. For a 5 m long cable with a 10 mm² cross-section, a 50 A current causes a voltage drop of 0.35 volts!

Generator starting excitation
Some generator types require a DC voltage at the B+ terminal for starting excitation. On the one hand, the connection between the battery and the generator provides a direct cable connection. On the other hand, the isolation diode prevents current from flowing back, preventing the generator from starting. The new Argofet battery isolation unit has a special current-limited connection for starting excitation when the generator is started.