Victron Argo Fet Isolator
Victron Argo FET Battery Isolators allow simultaneous charging of two or more batteries from one alternator (or a single output battery charger), without connecting the batteries together. Discharging the accessory battery for example will not result in also discharging the starter battery.
In contrast with diode battery isolators, FET isolators have virtually no voltage loss. Voltage drop is less than 0,02 Volt at low current and averages 0,1 Volt at higher currents.
When using ARGO FET Battery Isolators, there is no need to also increase the output voltage of the alternator. Care should take however to keep cable lengths short and of sufficient cross section.
Some alternators need DC voltage on the B+ output to start charging. Obviously, DC will be present when the alternator is directly connected to a battery. Inserting a Diode or FET splitter will however prevent any return voltage/current from the batteries to the B+, and the alternator will not start.
The new Argo FET isolators have a special current limited energize input that will power the B+ when the engine run/stop switch is closed.