KICKING IT UP A NOTCH

Meeting higher-voltage onboard needs requires systems changes that are underway now.

- ED SHERMAN

For years, I've been touting the advantages of 24-volt DC systems on boats. Higher voltage equates to lower current and less electrical resistive loss in an onboard electrical system. Boatbuilders say that the primary reason they have not adopted 24 or higher voltages is a lack of available components. Well, rest assured, that is rapidly changing.

As with many marine systems, much of what we see on boats gets its start in much larger industry sectors, primarily automotive and recreational vehicles. In this case, the movement to all-electric or hybrid-electric propulsion systems in cars and light trucks is a primary driving force. Consumer demand for onboard equipment with functionality similar to a new Audi or Tesla plays a part as well. So, with that said, let's look at where we are today, and at how to think about upgrades on an older boat or accessory choices on a new one.

ELECTRICAL FUNDAMENTALS

One big worry about cruising boats and their wiring has to do with voltage drop, where battery-level voltage doesn't actually reach the appliance the battery is supplying. Boats will often have longer wire runs than automotive applications. All wire has some inherent electrical resistance that will lower the voltage at the appliance. This is acceptable, to a point.

The American Boat and Yacht Council and the International Standards Organization identify two levels of acceptable voltage drop for battery-powered direct current (DC) systems: 3 percent and 10 percent. The bigger the wire diameter, the less inherent resistance it will have. As for voltage, higher voltages mean that lower amperage is required to achieve the same level of power (watts).