As the launch date of your offshore adventure draws near, you finalize those decisions about your vessel’s alternative power sources, which up to this time may have been limited to an array of solar panels mounted on the stern arch or some other convenient horizontal surface. Adding one or perhaps even two wind generators to the charging system will ensure your radios, navigation equipment, running lights, refrigerator, watermaker and microwave have a steady source of amperage, drawing little from the engine alternator.
If you are in the market for a new wind generator, a handful of manufacturers produce some highly evolved systems, the best-known of which are Air-X, Ampair, Kiss, Red Barron and Rutland (for information about selecting a new wind generator, see “Power plucked from the air” in the May/June 2007 issue of Ocean Navigator).
Integrating a wind generator within the vessel’s charging system requires careful planning on two interactive levels, mechanical and electrical. I say interactive because where and how you install the system will have a direct effect on how well the turbine converts wind power into electrical energy. On the receiving side, the amount of battery storage available and the types of controls you install will affect how efficiently you can take advantage of generated power that otherwise could be wasted.
Deck and arch mounting
The basic rule governing the positioning of a wind generator is simple: make sure there will be an uninterrupted flow of air from all directions to the turbine. If the boat is swinging at anchor without a stern anchor set, wind will nearly always come from within a few degrees of the bow. On the other hand, strong tidal flows may alter the direction of the apparent wind, causing the vessel to lie broadside and roll in a heavy chop. The wind turbine will be less efficient while rolling, but since it pivots 360 degrees, it can still remain directed into the oncoming airflow and continue to generate power. When deploying the wind generator in marinas where shore power is not available — especially in Med-style marinas outside the U.S. — the vessel can end up lying in any direction with respect to the wind, all the more reason to keep obstructions, such as a mizzenmast or a wind steering air vane, as far away from the unit as possible.
A stroll through any marina frequented by voyagers will reveal a variety of mounting techniques for wind generators. One may be mounted atop a dedicated mast cut from aluminum, stainless steel or galvanized tubing, while another might be suspended from the inner forestay, or mounted on a stern arch — or even perched on a pole attached to the bow pulpit! Imagine trying to fly a drifter or a spinnaker with a 4-foot propeller whirling away 8 feet above the bow stem. This is fine for a live-aboard boat that never sails, but not for an offshore voyaging vessel.
Some vessels offer no alternative but to mount the unit to the mizzenmast head of a ketch or yawl rig. This approach seems admirable enough as long as the extra weight aloft does not interfere with the vessel’s righting movement. Another, more pragmatic concern looms over this installation: how easily can crew gain access to the generator, especially while offshore in unsettled weather, if the unit sits above the masthead?
The two most practical mounting strategies appear to be either on a vertical tube solidly affixed to the arch, or atop a dedicated mast tube, the latter being by far the most common solution.
The only potential problem with the arch installation is the difficulty in installing rubber mounts to absorb sound and vibration from the turbine at high speeds. Most of the wind generators available on the market today have undergone extensive redesign in recent years to alleviate excessive vibration, but at high wind speeds, especially above 35 knots, some turbines are still liable to scream from air cavitation. As long as the crew can live with the possibility of vibration at high speeds on an older model, the arch provides a solid base, keeping the deck clear of extra mounting tubes.
For deck installation, you will need to find a properly sized length of pipe and mount it solidly in either corner of the stern, making sure to buttress the main mounting pole with at least two diagonal support tubes. The connection between the diagonals and the main tube will probably be a custom fitting, while the anchors for the diagonals are typically swivel bases used for dodgers and biminis. Assuming you are preparing for an offshore voyage, securing the main pole with hose clamps is not advisable. Even the best-made hose clamps are bound to snap from constant twisting and vibration after a few thousand miles of hard sailing.
Veteran offshore sailor Dick Verbeck used a pair of stainless U-bolts to secure his Red Baron to the stern rail of his 34-foot Bruce Roberts-designed cutter Beatitude, which is home-ported in Long Beach, Calif. He further secured the main mounting pole with a pair of highly polished stainless diagonal tubes connected to the side stern rails with swivel mounts. The finished installation is a glistening, attractive, unobtrusive complement to the overall rear deck layout.
For wind generators prone to a lot of vibration, particularly older models, some skippers install rubber sound-absorbing mounting pads between the mounting feet and the deck. A loud mechanical rumble reverberating through the hull is the last thing you want to hear while sipping cocktails and watching the sunset in some palm-fringed anchorage in your little corner of paradise.
One way to demystify the deck installation process is to find a model that comes with an optional mounting kit. Boost Energy Systems of Berkshire, U.K., offers the Scanstrut stern mount kit for its Ampair 300 generator. Company spokesman David Sharman says the installation kit “is well suited to larger turbines and ‘posher’ vessels.”
Sharman adds, “The Scanstrut consists of [an 8-foot]-long, 3-inch-diameter aluminum, white powder-coated pole which accepts the [swivel of the] generator. The base has a universal ball and socket for easy mounting to any deck angle on the stern of the yacht. Two adjustable stainless steel bracing struts clamp to the pole at their upper ends and mount to the deck at their lower ends. These resist the thrust and inertial loads of the wind turbine. A stainless steel guardrail bracing strut is also included.”
The Air-X mounting system features a nine-foot powder coat aluminum pole with a tilting mast base, plus a pair of stabilizer poles and swivel clamps. Both the Ampair’s and Air-X’s main mounting poles may be disengaged from their diagonal struts and swung down to the deck to allow inspection and repair of the generator and turbine.
Regulators and controllers
The specific methods and electrical components you use in coupling your wind generator to the vessel’s charging system naturally will adhere to a combination of vessel needs and personal preference. Your wind generator may be integrated into a system that includes an extensive battery bank charged by two alternators, a bank of solar panels, a water generator and perhaps even a diesel genset. There are numerous ways to bring all of these devices together; as long as the overall system is safe and responsive to your charging requirements, your overall electrical system should serve you well.
As always with electrical work, the best strategy is to leave the job to a qualified marine electrician who knows the relevant U.S. Coast Guard requirements and ABYC guidelines. If you intend to do the job yourself, be sure to follow manufacturer guidelines in connecting their products to your vessel’s electrical matrix. The installation manual should include such details as recommended wire sizes and types of fuses and diodes to prevent fires and equipment failure.
Fortunately, most of the popular wind generator manufacturers offer controllers designed specifically for their units. A few offer a choice between a traditional shunt regulator, which uses heat dissipation to discard excess charging amperage, and a smart controller, which regulates both amperage and voltage through a microprocessor. If your wind generator does not come with its own internal regulator or controller, you will need to select a control system in order to prevent battery overcharging and further damage to your vessel’s electrical system.
In the case of an off-the-shelf controller or regulator, make sure it is matched for the maximum output of the wind generator, lest you fry the control device. Some controllers, such as those available from Sunsei, are designed strictly for solar panels, which generally produce less amperage and do not impose the powerful surges produced by wind generators.
Another problem to watch for is pre-regulating a wind generator that uses electronic self-braking technology, such as that found in Southwest Windpower’s Air-X. The Air-X’s internal controller dampens the turbine to a slow spin when the battery has reached its full charge or when wind speeds reach light gale force. If the battery is receiving a charge from more than one source simultaneously, the Air-X may read the other input current as battery charge and prematurely drop to a slow spin, having been pre-regulated by the interfering charge. Incidentally, this causes no harm to the Air-X’s alternator or controller. The company cautions the user to “test the possible interference by disconnecting the other charge sources to determine the possible interference source.” The easiest solution to pre-regulation is to run all sources, except the engine alternator, through separate switches so that the operator may select inputs manually.
Yet another danger to your charging system is a powerful surge emanating from the engine alternator and sizzling any controller or regulator not rated for the alternator’s output. Small, unprotected controllers for alternative charging devices have been known to burn quickly, spewing noxious smoke upon the engine’s starting. A switch, fuse, or protective diode — or better yet, all three — between the battery and the control device will safeguard the device from harm.
Combining energy sources
A convenient way to manage alternative power sources is to combine them in one controller. Boost Energy’s configurable regulator combines the Ampair wind generator’s input with a solar panel array and is adaptable to a 12- or 24-volt battery bank. In addition to two input ports, the system also has two output ports, allowing you to distribute power to separate battery banks.
The Rutland 913 Windcharger, a wind generator built by Marlec Engineering of Corby Northants, U.K., may be coupled with a solar panel of up to 50 watts with the optional SR200 controller. The SR200 is a shunt-type regulator housed with an ammeter, dual battery voltage LEDs, fuses, and a switch for charging one or two isolated battery banks.
SES Flexcharge of Charlevoix, Miss., offers a fascinating little apparatus they call the NC25A Ultra High Efficiency 25-Ampere Solar and Wind System Charging System Controller. Roughly the size of a single-patty cheeseburger, the NC25A combines alternative energy charging systems from 0.1 amp to 25 amps and is expandable to 35, 60 or 100 amps for larger charging systems. Flexcharge claims an incredible 99.9 percent efficiency rate for the NC25A. And rather than shifting through bulk, taper and float charge levels, the little controller adjusts itself gradually depending on the precise levels of charge demanded by the dual battery banks.
The NC25A’s charge-divert feature routes excess charging energy to other tasks, such as refrigeration or a water heater, or back to a permanent magnet charging source, such as a wind generator, in order to dissipate energy and, in this case, to reduce turbine speed in high wind conditions. The charge-divert feature activates only after the battery banks have reached their full charge.
The Flexcharge family of controllers has played a vital role in seismic and geological research, an industry that demands instruments of high precision and close-tolerance calibration, explains company founder Don Seelye. On A22A, an iceberg the size of Delaware in Antarctica, Flexcharge controllers regulate charging systems employed to power GPS tracking equipment. The company’s charge controllers are also at work on a joint project by the University of California, Jet Propulsion Laboratory and NASA, supplying power from solar panels and wind generators for equipment measuring tectonic deformation in the West Antarctic rift system.
The final touch on your multisource charging system should be a dual bank battery monitor, such as the Xantrex Link 2000, which indicates charge source output as well as battery charge. The Link 2000 includes an extra shunt for the engine alternator in order to bring battery charge to maximum capacity.
Voyagers Richard and Kathy de Grasse, who installed an Air-X on their vessel as an adjunct to the solar panels, offer testimony to the advantages of a well designed, properly installed wind generator. Richard writes, “When we are motoring, all three house batteries are being charged. In the event of low batteries, we could, with simultaneous wind and solar charging, shut off all electrical equipment on the boat and bring the batteries up enough in a few hours to start the diesel.” (“Voyagers recount wind generator installation,” Ocean Navigator, July/August 2002.)
As long as you are not using your vessel’s battery banks to run the anchor windlass or an arc welder with the engine off, you can expect your alternative energy sources and charging controls to keep the beer cold, the pressurized water hot and the cabin fans whirring with little or no maintenance for many years.
Bill Morris completed a circumnavigation, two-thirds single-handed, via the Suez and Panama canals aboard his 1966 Cal 30 Saltaire. He believes the main reason for the success of the voyage was his preference for manual systems wherever practical, and dependence on alternative energy to power a minimal array of essential electronics. Morris’ book, The Windvane Self-Steering Handbook, was published by International Marine in March 2004.