Argo FET Battery Isolator 100-3 3 Batteries - 100AMPSimilarly to diode battery isolators, FET isolators allow simultaneous charging of two or more batteries from one alternator (or a single output battery charger), without connecting the batteries together. In contrast with diode battery isolators, FET isolators have virtually no voltage loss. Voltage drop is less than 0,02 Volt at low currents and averages 0,1 Volt at higher currents.Please contact your dealer for any returns, repairs or support issues related to this product.