Mastervolt Battery Mate 1603 IG Isolator - 120A, 3 Bank 
Battery Mate 1603 IG Isolator - 120 Amp, 3 Bank
The Battery Mate is the ultimate solution for charging several batteries simultaneously and is compatible with any type of alternator/battery charger, in both existing and new systems. As the voltage loss between the alternator and battery is negligible, the Battery Mate performs far better than conventional battery isolators. This ensures fast and complete charging of your batteries without having to make additional adjustments to the alternator.
While battery isolators are conventional diode splitters, the Battery Mate's technology is electronic and includes mosfets (transistors). Its components compensate for variations in voltage and ensure that charging continues at the right voltage level, even with several battery banks. The input side on the Battery Mate is connected to the alternator and/or battery charger, while two batteries are connected to the output side. The Battery Mate is easy to install on a DIN rail (industry standard).The Mastervolt Battery Mate can be used in any application even if the standard alternator need external excitation or voltage sensing. In this case the additional IG contact can be connected.
WARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.
Quick Guide (pdf)
Owner's Manual (pdf)