Victron Energy DC-DC Converters

Sizing a DC-DC converter correctly

A DC-DC converter earns its place wherever two circuits run at different voltages, or where you need to charge a battery bank from an alternator or another bank without the voltage sag of a straight cable link. The two figures that matter most are input voltage range and continuous output current: undersizing the converter against your alternator's realistic output leaves capacity on the table, while oversizing it without adequate cable and fusing risks nuisance tripping or overheating.

Isolated converters break the electrical connection between the two circuits, which is usually the safer choice where a lithium bank and a lead-acid starter battery share the same vessel electrical system. Non-isolated units are simpler and more efficient but only suit systems that can share a common negative safely.

Cable gauge and fuse rating both need to match the converter's rated current, not just the battery size, and the converter should be mounted somewhere ventilated, since most units derate their output as ambient temperature rises.