Simple, lightweight kits that top off batteries while on a mooring to more robust systems with rigid modules that can fully recharge batteries and supply extra power for running lights and appliances on board are all available as solar systems for maritime applications. Larger systems are often employed to lessen the need for engine power recharge, however boats without engines are capable of running entirely on solar power. Most systems are straightforward enough for do-it-yourself installation, and standard marine solar is 12-volts.
Boat modules are available in a wide range of kinds and sizes to accommodate a wide range of installation possibilities. Small units come in rigid, foldable, and rollable varieties and are designed to be portable and easy to store. You just remove them as needed and place them in a sunny location. Typically, modules that produce less than 1 amp can be connected to battery terminals for trickle charging or inserted directly into a 12-volt outlet. There should be a fuse in the circuit close to the battery. Depending on the size of your battery, select a module size for trickle charging:
module output (in milliamps; mA) ÷ 2 = battery capacity (in amp-hours)
For instance, a 200mA module can be used to gradually charge a 100 amp-hour battery (which requires about a 3 6-watt module). Rigid framed panels or flexible modules, often with 30 or 36 cells, are options for larger modules for boats. Typically, rigid modules are attached to rails or posts with specific fittings or are permanently fixed to metal racking. Additionally, they are suspendable by wires, enabling the module to be oriented in any direction toward the sun. Flexible modules are simple to move and store as needed since they can be fastened down practically anyplace. On the other hand, flexibility comes at the expense of efficiency, necessitating bigger or more modules to provide the same output as rigid ones. Modules may be connected to a 12-volt circuit with fuses close to the battery and the module, or they may connect to a circuit breaker in the vessel's DC distribution panel, depending on the module output and the layout of bigger systems.
Charge Controllers & Batteries
For solar panels with an output of 1 amp (12 watts) or higher, a charge controller is advised. To match the overall module output, charge controllers are rated in amps. Small controllers, also referred to as "regulators," are frequently made for charging a single battery or small bank of batteries. Larger units typically include features like maximum power point tracking (MPPT) to increase the charging current and enhance the charge during relatively low production times. They can typically charge one or two battery banks.
True deep cycle batteries are the finest kind for solar systems since they have the most storage capacity and longest lifespan of any battery-based solar systems. Many boats feature two battery systems: one that uses a deep-cycle battery to power the "house" and another that utilizes a starting battery to start the boat's motor. A dual-purpose battery, which provides the high starting amperage of a starting battery and can sustain severe discharges like a deep-cycle battery, is typically used in boats with only one battery system and one kind of battery. Dual-purpose batteries are only advised for small boats with low home power loads and for boats that utilize two dual purpose batteries for both starting and house power since they have a lower capacity than deep-cycle batteries.
Be Out of the Shape
On the open sea, there is a lot of solar potential. There are no problematic trees, and boats or modules may frequently be relocated to maximize production by facing the sun. However, it might be challenging to locate a location on a boat that isn't at least partially covered by a canopy, sail, mast, rigging, or other piece of necessary gear. Due to the tiny modules (and hence reduced energy margins) of the majority of naval systems, even a little degree of shadowing may significantly alter the amount of power produced. Here are some pointers for increasing output when it matters.
Keep portable modules out of the shade by moving them as often as necessary to keep them in the sun for the entirety of the day, especially during the two to three hours before and after noon. Fixed module mounting positions should be carefully chosen to prevent shade. Use adjustable mounts: You can tilt and rotate rigid modules of various sizes to face the sun by using adjustable mounts. Spread out flexibles: Although a module that is wrapped around your sail is conveniently out of the way, it won't be as effective at absorbing solar energy as one that is set flat. Module cooling: When solar modules heat up, they all lose efficiency (rigid lose more than flexible). In order to promote airflow that helps keep temperatures down and reduces this efficiency loss, leave ventilation space behind modules.