Victron Argofet 100-2 100A FET battery isolator for 2 batteries

Argofet 100-2 Two batteries 100A from Victron

Similar to isolating diodes, FET isolators allow two or more batteries to be charged simultaneously by a generator or charger connection without connecting the batteries to each other. A discharge of the on-board battery does not lead to a simultaneous discharge of the starter battery.

In contrast to isolating diodes, there is practically no voltage loss in FET isolators. The voltage drop is less than 0.02 volts at low currents and only 0.1 volts at higher currents.

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

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

Generator starting excitation
Some types of generator require a direct voltage at the B+ pole for starting excitation. On the one hand, the connection between the battery and the generator provides a direct cable connection. On the other hand, however, the isolating diode prevents the current from flowing back, so that the generator does not start. The new Argofet battery isolator has a special current-limited connection for the starting excitation when the generator is started.