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Electrical needs

Jan 1, 2003

Thirty years ago we took our first year-long voyage - including the crossing of 2,200 miles of open ocean from San Francisco to Hawaii and a 2,500-mile return trip - in our 31-foot Mariner ketch. For navigation we used a sextant, a mechanical log line, and paper charts. We had ice to cool our beer and fresh vegetables for the first four or five days. For safety we relied on our eyes: our boat had no radar, no radar alert system, no radar reflector, no EPIRB, no GPS.

On that first major voyage, our boat was equipped with a single 110-amp deep-cycle battery. That battery powered everything electrical aboard the boat, including the starter on the Perkins 4-108 diesel. We had no facility for charging that battery except for the wimpy 55-amp alternator on the engine that began reducing output within minutes after we started up. Yet we didn't feel electrically deprived. We had equipped our boat exactly as did the majority of cruising sailors making ocean passages in those days.

The electrical usage on most voyaging boats today, including ours, has increased exponentially. Whereas our voyaging boat 30 years ago consumed five to 10 amps per day when we were making an ocean passage or hanging on the anchor, our current boat consumes about 150 amps per day. And, according to the boaters we've interviewed here in Mexico this season, our consumption is typical.

With such electrical usage, members of the voyaging community engage in frequent and lengthy discussions about the replacement of that energy to their batteries. While some voyagers we've met here in Mexico have expressed overall satisfaction with their electrical systems, most would make some changes in their charging systems were they to set them up again. At the same time, rare is the boater who talks of giving up any of the comfort and safety equipment that consumes all that electricity.

The problems resulting from the large amp requirements surface for most voyagers when they begin to linger for days at a time in one captivating anchorage after another or when they leave Mexico for a long ocean passage. Even a boat with a large battery bank will be unable to stay out for more than two or three days without putting some amps back into the bank. Replacing the 300 amps that most voyaging boats use over a two-day period requires hours, not minutes, of charging time, whether by engine, genset, solar panels, or wind generator.

None of the cruisers we interviewed see themselves as having the "right" solution, and most eagerly listen to what works for others. Nevertheless, despite the dissatisfaction with their electrical generating systems, their boats showcase practical solutions that could be instructive for those voyagers getting their boats ready for a long passage.

High-output alternators

Of all the voyagers we interviewed in Mexico, only one had not installed a high-output alternator before departing on the current voyage. When used in conjunction with one of the modern voltage regulators, these alternators do a marvelous job of refilling the batteries.

For example, when a voyager is sailing here in Mexico and stops in an anchorage at 1500 on one day, a high-output alternator will replace most of the energy used that afternoon and night within an hour after getting underway the next day. As long as that voyager runs the engine to move from anchorage to anchorage every day or two, the energy level stays up. But few voyagers want to leave a beautiful anchorage after only one day. And that's where the study of amp usage and replacement becomes important.

On a boat with the typical usage of 150 amps per day and an average battery bank of around 600 amps, for example, some of that energy will have to be replaced every two days to avoid damage to the batteries by drawing them below 50% of their total capacity. The first solution occurring to many boaters is to start the engine and let that high-output alternator fill the batteries. But that solution brings more than just recharged batteries.

When they were outfitting Tigger II, Roger and Jean Weiss decided to install five solar panels and a Four Winds wind generator so they could avoid using the engine or a genset to charge batteries. They pointed out that running the diesel for an hour or two raises the temperature in the cabin 10° F or more. In Mexico, and in tropical destinations in the South Pacific where they're planning to go, cabin temperatures typically reach into the high 80s during the afternoon; adding more heat seems like a bad idea.

A second reason not to run the engine to charge the batteries has to do with the potential damage to the engine itself. When boaters charge the batteries at anchor, they typically run the engine at a fast idle, say at 900 rpm. At that engine speed, the engine does not have a load on it, and some diesels do not warm up sufficiently without a load. As Scott Harkey, on Viva, noted, running a diesel engine for long periods without enough temperature can cause excessive wear, glazing of the cylinder walls, and carbon build-up inside the engine. Although Viva has a high-output alternator, Scott and Debra do not use it to charge batteries when they're at anchor.

A third consideration for voyaging sailors on boats with small fuel tanks is fuel consumption. Though the amount of diesel used to run an engine for an hour may be less than a gallon, running an average of an hour or two a day for any length of time can clearly affect how frequently one must go in search of a fuel source. In Mexico, both along the Pacific coasts of Baja and of the mainland as well as up in the Sea of Cortés, fuel stops are few.

For all these reasons then, most voyagers choose not to run their engines to charge batteries when at anchor. Though most have installed high-output alternators, they plan to use them for charging only when underway. When outfitting Harmony, an Orion 50, for a cruise through the South Pacific after visiting Mexico, Bob and Teka Walsh installed a large-frame alternator to replace the energy while underway without running the genset. They say that they use "at least 150 amps a day" when at anchor or on an ocean passage, and that the large-frame 250-amp alternator charges the 900-amp house bank quickly without overheating, as a small-frame alternator would do.

Solar panels

More than half of the voyaging sailboats in Mexico this season have one or more solar panels aboard. Although not every boater who has chosen to install solar panels is happy with the choice, most are. Nick and Carol Rau are typical of the latter group. They installed two 120-watt Kyocera panels on Mucho Gusto, their custom Mull 45, and report that the electrical needs on their boat are "100% supplied by solar power when at anchor and under sail."

When asked why they chose solar, most voyagers we interviewed replied they favor solar because it has no negative effects. Solar panels are quiet, they add no heat to the boat, and they consume no fuel. In addition, many mentioned that the installation of solar is easier than that of any other electrical producing devices.

But many we spoke with listed some disadvantages, too. The most obvious of the disadvantages is cost. Some pointed out that the purchase price is about $100 per amp delivered to the batteries hourly under optimum conditions. That $100 per amp may not seem expensive until one multiplies that figure by the number of amps required to keep up with the energy consumption on a typical voyaging boat.

Eric and Corrinn Bates, on About Time, installed three 120-watt Kyocera panels on their Michelson 50, hoping to keep up with electrical usage. Their panels produce a maximum of 21 amps under optimum conditions, generally between 1100 and 1500 in the spring and summer months. Between 0800 and1100 and between 1500 and 1800, production is less than 21 amps. The amount produced at any time of the day depends, of course, on cloud cover, the angle of the panels in relation to the sun, and shadows on the panels.

Aboard boats sailing Mexico, cloud cover rarely creates a problem since this is the land kissed by the sun. But keeping the panels aimed at the sun demands more attention than most of us want to devote to the electricity production on our boats. For that matter, few solar panels are mounted in such a way as to allow for the adjustment needed to achieve maximum production. Although some panels cannot be adjusted at all, most can be adjusted on a single plane; a few can be adjusted on both fore and aft and athwartships planes. This lack of adjustment significantly reduces solar productivity in the early and late hours of the day.

Solar energy production in the fall and winter months also suffers if the panels cannot be fully adjusted. On our boat, our production is typically 19 amps during the peak hours during the spring and summer but only about 16 amps during the fall and winter months, at least partially because they are not fully adjustable.

Of all the variables affecting solar production, keeping an unobstructed path between the solar panels and the sun requires the most attention. Even the shadow of a mast across a panel reduces its output to almost nothing. On a sailboat at sea or at anchor, keeping shadows off panels becomes almost impossible. On New Adventure, Gerry and Michelle hoped their two large Siemens solar panels would meet their energy needs. But when we last spoke with Gerry, he was discouraged with solar power, saying that shadows reduce the output of one or the other of their panels during the majority of the day.

The solar panels that appear to be the least affected by shadows are those mounted on the transom of the boat. Unless the boat has a windvane or mizzen boom that casts a shadow over the stern, such panels will be free of shadows except early or late in the day, when the mast gets between the panels and the sun. By contrast, as in the case of the two panels on New Adventure, when a boat has panels on each side, one or the other will often produce less amperage because of shadows.

In spite of the practical problems with solar installations, many voyagers count on getting 80 to100 amps a day. And, given the typical consumption of about 150 amps daily, their boats are going into the minus range at a rate of only about 50 to 70 amps per day. The Bateses, on About Time, for example, have a house battery bank with about 700 amps and can generally sit in an anchorage for at least five days before they have to start their diesel or genset to charge batteries.

A large percentage of the voyagers we spoke with were glad they had invested in solar panels, but regretted they hadn't installed more. Harvey and Chris Duryee, on Malocclusion, a Catalina 42, have the typical daily amp usage of approximately 150 amps. Because they like to use their 12-volt fridge, their watermaker, their SSB, their stereo, their computer, and their microwave when at anchor, their two Siemens 75-watt solar panels cannot provide enough energy to keep their batteries full. Chris and Harvey commented that they wish they had understood solar power more fully when they were outfitting their boat.

All too often voyagers equip their boats with solar panels that are adequate at the time, but, as they install more and more equipment, their panels can't keep up with their consumption. For example, Stef and Marilyn Thorvarson, aboard Circe, a Panda 40, installed four Siemens 75-watt panels as they prepared for their current cruise. The boat has a 600-gpd watermaker, a refrigerator, a freezer, a microwave, VHF and SSB radios, and a few other items that voraciously consume 12-volt energy. As a result, their boat uses about 200 amps per day while their solar panels produce less than 100 amps per day, leaving them unable to keep up with usage. After being out on this cruise for four years, Stef commented, "You can't put on too many solar panels."

Gary Cook on Navigator, a 46-foot Beneteau, agrees with Stef and Marilyn. He and Diane installed three 90-watt Siemens panels, hoping these would meet their electrical needs. If they were to outfit their boat again, they would install two more 90-watt panels. They now believe two more panels - bringing their output to more than 25 amps during the peak hours of the day - would meet their boat's 150-amp daily usage.

Wind generators

The percentage of voyaging boats in Mexico equipped with wind generators this season appears to be close to 20 percent, a noticeable increase over past years. Although wind generators are increasing in popularity, those voyagers we interviewed gave them mixed reviews.

Some boaters expressed complete satisfaction with the amount of energy produced by their wind generators. Those who appreciated them the most didn't expect them to supply all the electrical needs of their boats. Most of these boaters had installed wind generators to supplement their other electrical-generating devices. Since the winds typically blow gently during the day in Mexico, wind generators produce a modest amount of electrical energy between sunrise and sundown. In many anchorages, however, the winds blow briskly during the night, making wind generators most effective when the solar panels are inactive.

Wind generators differ greatly. For example, some are virtually silent. Sailors around our boat regularly comment on how quiet our Four Winds unit is. Unless the wind is blowing at more than 20 knots and the air brake kicks in, no one can hear it. Other units, even other Four Winds units, can be noisy enough to be objectionable, both to their owners and to other boaters anchored nearby.

Most wind generators begin to charge when wind strength reaches six knots or slightly more, but charging remains modest until winds exceed 15 knots. At that point, serious charging begins. Some units charge at a consistent 10 amps or so when winds blow that strongly; thus the batteries could receive something in the neighborhood of 80 amps of energy in a single eight-hour night with fairly consistent 15-knot winds. Most of the voyagers we interviewed who had wind generators also had solar panels aboard. They state that the two together have reduced their need for engine charging while at anchor to nearly zero. Gary and Diane on Navigator installed an Air Marine unit on their boat to supplement the output of their solar panels. So far the combination of solar and wind power has produced enough energy to supply the demands of their equipment.

The cost of wind generators has dropped significantly over the past few years, perhaps explaining the increased number seen aboard voyaging boats. While the installed price of the Four Winds unit on our boat was close to $2,000 about 10 years ago, a boater can install the new Air Marine wind generators for slightly more than $1,000, according to the voyagers we've interviewed. Considering that most wind generators are capable of producing significant energy, we think they're a wise investment for most sailors.

AC gensets

The number of gensets aboard the voyaging boats this season has increased, just as the number of solar and wind units has. As with all other methods of generating energy, however, gensets do not make everyone happy.

The first objection to gensets is the initial investment cost. One voyager told us the replacement seven-kW genset in his boat represented a $9,000 investment. Two voyagers cautioned sailors against trying to save money by buying a unit smaller than they need. Both these sailors said they made that mistake. They advise voyagers who are setting up their electrical systems with gensets as major charging components to spend whatever they must to have a generator adequate for the system.

Just as alternators, solar panels, and wind generators have changed over the last few years, so too have gensets. Criticized as too noisy for years, gensets on modern boats are often quiet enough that few other boaters in an anchorage know when one is running. Even aboard a boat with a modern genset, the noise can be reduced to an acceptable level. We recently sat aboard Wally Schrick's Blue Tango, a Valiant 42, while the genset was running. Unless we stopped talking and listened carefully, we couldn't hear it because Wally had installed it in the extreme stern of the boat under the cockpit, separated by two insulated bulkheads from the boat's cabin.

The second common objection to gensets is that they increase the heat inside the cabin of a boat. Since most gensets are installed in the engine room, often in the center of the boat, increased cabin temperature during and after the genset use has been run is almost unavoidable. On Blue Tango, however, Wally has observed no increase in temperature as a result of running the genset, again because of its location at the extreme aft section of his boat and because of the two insulated bulkheads separating it from the living area.

Some who have gensets aboard worry about fuel consumption. Although a five-kW unit may burn only 2/3 gallon an hour, that amount can create a problem for a voyager who wants to spend day after day anchored out or one who wants to make long ocean passages. This fuel-consumption problem worries Wally because the tanks on Blue Tango hold only 90 gallons of fuel. He typically runs his genset at least two hours daily, using more than a gallon of diesel a day.

A more significant issue, according to some voyagers who have gensets aboard, has to do with depending too much on their units. One voyaging couple we know, Geoff and Yumi Curran, took their genset-equipped Norseman 447, Mandarin,from Honolulu to the Tuamotus, on to Tahiti, and back to Honolulu. Their genset, newly installed before they departed from Honolulu, went down on the first leg of their voyage. Since the refrigerator required 120-volt AC power, as did most of the other electrical equipment on their boat, they had to shut down the refrigerator, losing much of their refrigerated food.

At least a few of the boaters we interviewed in Mexico this season are also sailing boats with equipment set up to be dependent on the genset. Wally Schrick's Blue Tango is one such example. Even though his genset is virtually new, he does worry a little about the problem. As he put it, "This is an AC boat. The refrigerator, the watermaker, the battery charger, all run on 110-volt AC." But he feels fairly confident he will be able to get the genset up and running again if it goes down.

Many of the boats we saw with AC gensets had either an AC-powered refrigeration system or an engine-driven system. If their gensets run two hours each day, as appears typical, the batteries will be topped off and the holding plates in the fridge and freezer brought down to the ideal temperature on a daily basis. Ken Roth on Mariah, a Liberty 49, says such a schedule keeps everything aboard his boat running perfectly, but he still worries that his system is "too complicated" for him to keep it running while out voyaging. To avoid a total failure, he, too, has installed a high-output alternator on the main engine.

DC gensets

Though we saw only one example on the boats we visited in Mexico this season, the future of the DC genset seems promising. A number of manufacturers offer these simple units. Usually powered by a single-cylinder Kubota diesel or some similar engine, a DC genset drives a large-frame 160-amp alternator.

These units have one distinct advantage over AC gensets: they are cheaper. Scott Harkey and Debra Cutting installed one of the Power Genie units from PowerTap in Viva, their Saga 43, at a cost of about $4,000. (Apollo and Balmar offer similar DC generators.) When they start up their Power Genie, it both charges the batteries and runs the belt-driven watermaker. They installed their Genie far back in the engine room, just in front of the transom, and any heat produced while running it appears to be confined to the aftermost sections of the boat. Concerned about being dependent on their DC generator, Scott and Debra also installed a high-output alternator in case the Genie fails. Because this is their first season voyaging, they've not used their Genie enough to give long-term evidence of reliability. And since they have motored more than they expected to, their high-output alternator has kept their batteries so nearly full that the Genie has not been as important as it will be as they continue their voyage.

Other voyagers in Mexico have heard about the DC genset concept and are thinking about installing such a unit in the future. Gerry, on New Adventure, having tired of trying to keep his solar panels aimed at the sun and free of shadows, is considering building a DC genset. He believes he can get a small diesel, an alternator, and the remaining parts necessary for less than the cost of the three additional large solar panels necessary to make the boat entirely self-sufficient.

Because demands on the electrical system seem to increase every year, voyagers planning a passage should analyze their needs generously and then add more of whatever it is they plan to use to replace the amps in the batteries. Yet, despite careful planning and forethought, most of us who go voyaging find our attitudes about comfort items change as we go. When we interviewed Don and Judy Moomey, who sail Orioco, a Hans Christian 38 they've so far kept simple, they said they now want to add electrical refrigeration and an autopilot, even though they know these two additions will require more solar panels to supplement the single 95-watt Siemens they now have. They appear to be going the way we have all gone - for comfort and the inevitable complexity that supports it.

Even those boats that are already comfortable get more comfortable every year. Don and Tommy Hatten, on Wings, a Norseman 447, bought a boat already well equipped and then installed more comfort items, including two air conditioners. To be certain everything continues to work, they replaced the main engine with a new Westerbeke diesel and put in a new 7.5-kW Westerbeke genset. They also added two of the largest solar panels available. Their goal, like that of many voyagers with a genset, is to run it as little as possible, but they are willing to do whatever is required to be comfortable while voyaging.

Using the current fleet of voyaging boats in Mexico as indicators of the direction of the future, we've concluded that the majority of boaters want comfort along with their adventures. Most of these boats have GPS, computer navigation, radar, watermakers, autopilots, refrigeration, stereos, televisions, fans, VHF and SSB radios, lights, pressure water systems, and more, all run off the boat's batteries. The question for boaters heading out on a power will probably not be whether to add comfort items but how to supply the power for them.