Solar Panels on Boats
Posted on Marine equipment
Advantages of solar panels on boats include their ease of use, lack of maintenance, and longevity (some types last 20 years or more). Disadvantages include difficulties finding places to mount a large array, their weight (depending on the type chosen), and their bulk. In addition, large solar panel arrays require extensive electrical wiring and a solar regulator to prevent excess current from overcharging the boat’s batteries.
Solar panels produce DC electricity, so boats that require household-type AC electricity to run microwaves, stoves, or other systems (such as marine air conditioners and heaters) would need either generators or inverters to convert their solar-generated DC power into AC.
Rigid Solar Panels Feature Long Life Spans
In considering whether to add solar power to a vessel, boaters can choose between two main types of solar panels: rigid crystalline panels and flexible panels.
Rigid panels such as those produced by Kyocera Solar Energy, BP Solar International Inc., and Sharp Electronics Corp. are standard equipment in shore-based solar panel arrays. These solar panels generally are made of heavy glass and aluminum; because they are so large, bulky, and inflexible, they can be difficult to mount and to stow. Most boaters mount them permanently on a fixed structure such as a deck or a cabintop.
However, rigid solar panels require no maintenance beyond occasionally checking the electrical connections for corrosion, and they have a very long lifespan — warranties typically run two decades or more. In addition, they are less expensive than newer types of flexible solar panels, and they are more effective in bright sun conditions.
Flexible Solar Panel Benefits: Light Weight, Stowability
Development of flexible “thin-film” solar panels, such as those produced by PowerFilm Inc., has accelerated in the past five years, and the larger sizes now offer electricity generation that’s comparable to rigid solar panels in an extremely lightweight, easily stowed package (PowerFilm’s largest panel weighs just 2.6 pounds and will fit folded into a bag just three inches high by one foot square).
Flexible panels also are more effective in cloudy conditions than crystalline panels. However, convenience comes at a price: they are up to twice as expensive as rigid panels for the same output, and they wear out far faster. Warranties for thin-film solar panels generally only cover two to five years.
Solar Panels Measured in Watts
Manufacturers report solar panel size in watts and amps, which can be confusing for those who aren’t used to the terminology. For example, a large Kyocera 65 panel (one that measures 30 inches by 26 inches and weighs in at more than 13 pounds) is rated at 65 watts and 3.75 amps, and retails for under $400.
In practice, this large solar panel might produce about 3 amps of 12-volt electricity per hour for five to eight hours on a typical sunny day. This is enough to power a laptop computer for up to four hours to run navigation software, or to run four halogen lights all evening. Two of these panels could run a very small, extremely well-insulated marine refrigerator, although more typical marine refrigerators likely would require three or four of these panels to stay cool.
PowerFilm’s largest foldable solar panel, which measures 60 inches by 42 inches, is rated at 60 watts and 3.6 amps — about the same output. It weighs 2.6 pounds and retails for about $700.
This explanation from boater advocacy group BoatUS illustrates how to determine solar needs on a boat.
Marine Solar Panels: A Do-It-Yourself Project?
It’s certainly possible for a handy boat owner to install and wire solar panels. The first step is to determine whether to purchase flexible solar panels (which can be thrown over a bimini cover or rolled out on deck) or rigid solar panels. If the choice is rigid panels, then the boat owner will need to devise a mounting system.
Most systems also require a solar controller. The solar controller, which may not be necessary for tiny “trickle charge” solar panels but is needed for any array larger than about 10 watts, will moderate the electrical current produced by the solar panels so that the batteries do not become overcharged.
All in all, solar panel installations can be complex and costly. However, once the installation is complete, boaters can enjoy green, silent, simple electrical power, in some cases for two decades or more.
On smaller boats that spend significant time away from the dock, solar panels can produce most or all the energy needed to run the vessel’s systems. On larger boats, an extensive collection of panels can reduce or even eliminate the need to run the engine or generator. In addition, adding such energy-saving devices as LED lights can help make the solar panel system even more effective in meeting the vessel’s energy needs.