Offshore Sailboat Electrical Systems: What We Use Aboard One World
Since One World Sailing Academy is heavily focused on vessel systems, along with the operation, maintenance, and management of those systems offshore, the following article will discuss many of the electrical systems we currently use aboard our vessel One World, our Amel Super Maramu 2000. There are many good brands and system configurations available in the offshore cruising world, and there are certainly other systems that work well too. The purpose of this article is not necessarily to say one system is the only correct choice, but rather to discuss some of the systems we currently use aboard our vessel, along with why electrical systems become so important in offshore and blue water cruising. One of the first major systems aboard One World is the electrical system itself. From the factory, the boat was designed as a European-built vessel, so it utilizes a 24-volt DC electrical system along with a 220-volt AC system. In addition to that, we utilize 24-to-12-volt converters to operate many of the onboard electronics and accessories that require 12-volt power. That includes systems such as: Even on a 24-volt boat, there are still a significant number of components and accessories in the marine world that operate on 12 volts, so proper voltage conversion and power management become important parts of the overall electrical system design offshore. One of the questions people often ask is: why use a 24-volt system instead of a 12-volt system aboard an offshore cruising boat? One of the major advantages of higher-voltage DC systems is efficiency. As voltage increases, amperage decreases for the same power demand, which means smaller wire sizes can often be utilized throughout various onboard systems. In practical terms, many 12-volt systems require significantly larger wire sizes compared to equivalent 24-volt systems carrying the same electrical loads. That becomes especially important on larger offshore vessels where wire runs can become quite long and electrical efficiency matters. Overall, 24-volt systems tend to operate more efficiently for larger cruising boats with heavier electrical demands. Those remaining 12-volt requirements are easily handled through the use of DC step-down converters. On our vessel, we utilize Victron Energy 24-to-12-volt converters to power many of those systems. Over time, I upgraded the original converters aboard the boat from smaller 12-amp converters to larger 20-amp converters in order to increase system capacity and allow additional room for future system expansion and electrical demands. In addition to that, because the vessel was originally designed around European 220-volt AC power, there are some differences when operating the boat in the United States, where 120-volt appliances and utilities are far more common. For years, we’ve handled that by utilizing portable 220-to-120-volt step-down transformers plugged into outlets in various locations throughout the vessel, which then provide standard 110/120-volt power for U.S.-based appliances and equipment. That setup has worked well for us over the years, but we’re currently in the process of changing and upgrading that part of the system to create a more integrated onboard 120-volt solution. To improve that setup, I recently purchased a Victron Energy 3000-watt inverter system. The inverter utilizes 24-volt DC input and provides 110/120-volt AC output, allowing us to create a dedicated onboard 120-volt electrical system alongside the vessel’s original 220-volt system. That inverter will feed a dedicated AC distribution panel with three separate 120-volt circuits. One circuit will supply the aft cabin, aft restroom, and possibly the walkthrough cabin area. A second dedicated circuit will feed the galley alone, including multiple outlets intended for higher-demand appliances commonly used in the galley. And the third circuit will supply the forward cabin and forward head. All of those new circuits will be wired as dedicated 110/120-volt systems. So aboard the vessel, we will now have both 220-volt outlets and 110/120-volt outlets available throughout different areas of the boat. Regardless of the specific power requirements of onboard equipment or personal electronics, we’ll be able to accommodate both systems aboard the vessel. Our shore power system is configured around a 220-volt shore power inlet, which matches the vessel’s original European electrical design. We also utilize an onboard transformer system, which gives us flexibility when connecting to different shore power standards around the world. If 220-volt shore power is available, we can plug directly into that system. But we can also adapt the vessel to utilize 110/120-volt shore power by simply changing the plug configuration at the end of the shore power cord and switching the transformer input configuration accordingly. That flexibility allows us to operate the vessel in marinas and facilities utilizing either 220-volt or 110/120-volt shore power systems. We also carry multiple international shore power plug configurations that match various power systems used throughout different parts of the world. In most cases, we’re simply changing the plug adapter itself rather than replacing the entire shore power cord. In addition to that, the vessel is equipped with an Onan generator system rated at approximately 7 to 7.5 kilowatts. It’s a 50 Hz, 220-volt generator designed to support the vessel’s primary onboard AC systems and overall electrical demands while offshore or away from shore power. When operating, the generator is capable of powering virtually the entire vessel with some reasonable power management employed onboard. That includes systems such as: In addition to the generator system, the vessel is also equipped with three 475-watt SunPower solar panels. Those solar panels provide a significant amount of renewable charging capability offshore and have dramatically reduced our dependence on the generator during normal day-to-day cruising operations. Under typical sunny conditions, the solar array is capable of fully charging the battery banks into float mode on a daily basis. Because of that, the generator has effectively become more of a redundant backup charging system rather than a primary daily power source. That level of charging capability becomes extremely valuable offshore, especially during extended periods at anchor or while living aboard full-time. The vessel is also equipped with a 4,000-watt Magnum inverter system utilizing 24-volt DC input and 220-volt AC output. We originally installed that Magnum inverter