Isolated DC/DC Converters are a cost method to draw 12 V power off the entire pack and maximize not only the life of the batteries, but also the range of the vehicle. Some battery manufactures will not warranty batteries for early failure unless 12 V loads are powered by a DC/DC converter.
Isolated converters are appropriate for wet, corrosive or dusty environments. They protect the converter from damage due to inadvertent shorts to frame and they can help protect the 12 V loads against a single point of failure.
There are a number of isolated models to choose from:
46/36 VDC Input
16 Amps constant, 20 amps intermittent
With input& output fuses in harness, PN 30100
Fully encased in metal and connectorized with Deutsch Connectors, PN 14165