Articles about Catamaran Electrical Systems

If the AC electrical load on your boat is large enough, you'll probably need to look beyond the capabilities of DC-to-AC inverters.  Even if you have a large inverter that can handle a large AC load at any given moment, in most cases the charging system needed to replace battery drain becomes impractical unless your large AC loads are used primarily when plugged into shorepower. A good example of an AC load too large for most inverter installations is air conditioning.  The instantaneous AC current draw from air conditioning ranges from fairly modest to high, depending on.....

While it's easy to cruise successfully with only DC electrical appliances, it's natural to want the option of using inexpensive household galley appliances, power tools, and work or entertainment electrical devices on board.  Imagine a silent, lightweight, affordable AC power system on a sailboat.  A few years ago this was unthinkable, but the new generation of efficient DC-to-AC inverters have made these type of AC power systems a reality, creating a quiet revolution in the way multihull owners use electrical power.  There are two basic methods for supplying AC power.....

When laying out our electrical power system we often neglect the AC side things. AC here refers not to air conditioning, which many modern multihulls choose to include in their list of appliances, but to alternating current, the same type of power found in a house or dockside. In this series of articles we'll review the various options for providing AC power and the system components needed to make your system functional and safe.Let's begin with the Shorepower supply, since almost most cruising multihulls have provisions for hooking up to dockside power. The simplest type of system has one.....

You're heading offshore and have come to realize that almost every important system on your boat depends on a steady supply of electricity. You find yourself asking, "will I have enough electrical power on board, especially when I really need it?" Good question. To answer it you first need to take a close look at your projected daily electrical load and see how that compares with the amount of electrical power you can reliably provide on a daily basis. Most multihull sailors preparing for blue water cruising these days find their electrical power situation is unbalanced-too much load for t.....

Multihull sailors attempting to make and manage their own electrical power supply must have some way of storing electrical power for later use. With renewable power sources such as solar, wind and water chargers it's essential to take advantage of favorable charging conditions while they last. And with engine-driven charging sources it's best to be able to charge at the highest rate possible while the engine is running, then tap your stored electricity until it's time to generate again. Although many energy storage mediums have been proposed over the years, lead-acid batteries remain the most.....

Multihull sailors need adequate charging sources to routinely replenish the battery power they use, and the proper controls for those charging sources to protect and extend the life of their battery banks on board. In this two-part column we'll review the charging controls on the market and their operation. Each charging source you install on your boat must have some sort of charging control to limit or shut off the current once the batteries are full. Alternators and other charging sources are designed strictly to provide power, a given amount for the conditions they operate.....

Those sailor's building a new multihull or renovating an existing one are eventually faced with the task of wiring from scratch or rewiring the DC side of the boat's electrical system. This process can be less daunting if you understand what DC circuits are all about, and spend time planning for a proper installation. Think of a circuit as a path that, if followed completely, leads back to the starting place. In this column we are concerned with electrical circuits that provide a reliable path for direct current (DC) on a sailing multihull. While there are definite rules to foll.....

There has been growing interest in electric propulsion for sailboats. The lure of clean, silent electric motors capable of replacing the diesel auxiliary inboard(s) seems to be especially strong for multihull sailors, but then they have always been able to think outside the box and are, in general, more open to new concepts than their single-hull counterparts. Despite their forward thinking and willingness to embrace new technologies, however, they ultimately want equipment and systems that work well. And they are, in general, quite willing to spend some extra money on elegant solutions on.....

An electrical power system on a boat is comprised of various electrical circuits. A circuit can be thought of as a path that if followed completely leads back to the starting place. An electrical circuit refers to a complete path for electrical current flowing through wires. An electrical circuit is formed by connecting a voltage source such as a battery bank or AC power source to one or more electrical loads (appliances that use electricity) by means of a conductor, typically copper wire. In a DC battery circuit battery voltage pushes electrical current through various electrical loads w.....

If you have a large AC electrical load and spend time away from dockside shorepower, you'll probably need to look beyond the capabilities of DC-to-AC inverters and start investigating gen-sets. Even if a properly sized inverter is capable of handling your load, the charging system needed to replace battery drain may well be impractical. A good example of an AC load too large for most inverter installations is air conditioning. The instantaneous AC current draw from air conditioning ranges from fairly modest to high, depending on the BTU rating of the unit. But it's not the curr.....

Beyond the glamor of high-output alternators, solar and wind chargers, battery banks and system monitors are the hidden essentials of any respectable marine electrical power system, those heavy-duty DC circuit components that provide safe, efficient wire termination points and switching ability. Long ignored by boat owners, boat manufacturers and electrical system suppliers, these important pieces of gear are now standard equipment on most high quality marine installations.I use the term "heavy duty" to describe this class of electrical devices, not to imply that they all have the same degree.....

Part I - Do I need a high-put alternator? If your multihull has an inboard auxiliary engine and you want the most charging amps for the least expense and maintenance, you should consider replacing your standard alternator with a high-output model.  It's not unusual for sailor's to get four or five times the power output of their existing alternator for a relatively modest investment.  It helps to know that standard alternators are mass produced, adapted from the automobile industry with minor modifications for marine use.  They're fine if you use your boat like a car.....

The key to success with a boat, regardless of how many hulls it has, is a simple matter of balance.  Designers must balance sail area with stability and speed with comfort, just as owners must balance their time aboard with their time ashore and the gear they want with the design limits of their boat and the money they have.  The same applies to the various systems on a boat.  Problems arise from a lack of balance, and nowhere is this so evident as in the electrical power system. The peace of mind that comes from producing as much electrical power as you use is e.....

How many times have you heard that electricity is mysterious, unfathomable, beyond the ken of the average human?  The difficulty in understanding electricity is derived from the fact that we can't see it.  We can see its effect in a light bulb, hear its effect when a radio is turned on, or feel its effect when we operate a fan.  We can understand the work being done, but not the electricity itself.  For most of us, a great deal of the mystery surrounding electricity would be removed if we could see electricity as it was produced, directed into our batteries, and u.....

Last issue we looked at the charging power available from high-output alternators. While these units do produce a tremendous amount of power for the price, there are many multihull sailors who don't have an inboard engine or who would rather not put the wear and tear of routine charging on their inboard(s). Alternative engine-driven charging sources include self-contained portable generators and DC chargers. Their advantage is that they match electrical output with engine size, maximizing efficiency. Portable generators such as those offered by Honda and Kawasaki have been used ef.....

PV solar panels are now an accepted part of a cruising boat's electrical power inventory, and rightly so—they produce consistent power year after year with no noise, smell, or moving parts.  They are especially popular on multihulls, where panel mounting options are numerous. Unlike solar panels used for heating, PV ("photovoltaic") panels convert light energy directly into electricity through the use of thin, specially treated silicon cells.  When exposed to sunlight, each cell in a panel produces about 0.5 volts, regardless of cell size.  Roughly 36 cells are conne.....

One of the best ways to make sure there's always enough battery power on board is to reduce your electrical demand where possible. This doesn't mean you have to give up conveniences or safety gear you've come to enjoy and rely on. Most multihull sailors can reduce their electrical load significantly simply by choosing efficient appliances and operating them wisely. Reducing electricity use before selecting charging gear is similar to insulating a house before selecting a heating system. Reducing demand can get you most of the way toward self-sufficiency and the ability to use.....

Sailors in the North American market have become accustomed to the concept of having an inverter (a unit that takes DC battery power and "inverts" it into household AC power) and an AC-to-DC battery charger in one neat package.  At first glance these combination ("combi") units seem to have several main advantages over having a stand alone inverter and charger.  With a combination inverter-charger there is only one piece of equipment to purchase and install, and the cost is typically lower than for separate stand alone units.  Combi units also have an internal trans.....

Multihull sailors who intend to go cruising, but who presently use their boat occasionally or have dock space with shorepower available, should prepare for being able to make and manage their electrical power supply under cruising conditions.  There is nothing more frustrating than arriving at a great cruising ground only to realize that you are ill-equipped to maintain a reliable supply of electricity, and running the engine for hours on end in an idyllic anchorage can make you wonder why you bothered to leave home in the first place. When I design a power system for a sailor wi.....

These days the electrical power system on board a cruising multihull has to be rugged, reliable and, most importantly, easy for the crew to understand and operate. How hard is it to find a system that meets all these criteria? Easier than you might think, especially if you take the right approach to system planning. As a first step I recommend you assume the role of system manager of your own private utility company, for that adequately describes the situation you'll be in whenever you leave the dock. There are rewards and responsibilities that come with the territory. Your best chance of.....

Of the three renewable charging sources for marine use, water-powered generators are the most overlooked and least understood.  The fact is that they can be an important part of your independent power system, quietly, reliably producing large amounts of electrical power whenever you are under sail.  Water-powered generators take advantage of the relative motion between a sailboat and the surrounding water, and so actually use the wind for mechanical power, unlike land-based water-powered generators that rely on falling water under the influence of gravity.  Multihu.....

Sailors have known for centuries that wind energy can be harnessed to propel boats, but only recently has it become accepted that the energy in the wind can also be used to create clean, renewable electrical power on board.    Wind-powered generators for marine use were introduced in the mid-1970s, and they have been constantly improving since then.  Wind units currently on the market can produce a formidable amount of electrical power, but only you can decide if wind power is right for your needs and, if so, which particular model is best. All wind generators c.....