The Benefits of Solar Power for Boats

Looking for an innovative way to recharge the batteries on a boat when away from the marina? The technology for solar power for boats has matured in recent years and can help top off batteries to increase reserve power for later use.

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Modern electronics for navigation and communication need plenty of juice, especially considering people's desire to be constantly connected online. To power these instruments, deep cycle marine batteries are needed to store enough power until the boat has reached the next marina to recharge and refuel. Solar cells can help extend the duration between marina pit-stops.

Considerations - Is Solar Power Right For Your Boat?

  • Rigid solar panels provide more power than flexible solar panels.

  • Permanent mounting. There's only limited area on the deck to permanently mount panels (i.e. near the front of the mast or on the side of the hull). Commercial panels are sturdy but are not designed to be constantly stepped on. More ruggedized units are available but are very pricey.

  • Holes in the hull. Extra mounting holes in the deck are required, but drilling through the hull is what all boaters try to avoid.

  • Flexible (and semi-flexible) solar panels. Flexible units can be temporarily rolled out on the deck but they do not provide as much power as solid units.

  • Temporary mounting. Flexible solar panels are lightweight but may not withstand the wind or water on the open deck. And although these units can be rolled up like blankets, they will still take up valuable indoor storage space.

  • Needs full sunlight. Solar panels need full sunlight to work at peak performance. A shadow from a jib or main sail will reduce its efficiency even if only a portion of the solar cell is blocked from the sun.

  • Charge controller. A charge controller with Maximum Power Point Tracker (MPPT) is needed to optimize the current/voltage ratio from the solar cells. These units are small but the power cables will still need to be sized appropriately for the panels. Another hole in the hull will be needed for these cables.

Drawbacks of Using Solar Power for Boats

  • Only rigid panels should be permanently installed on deck as they can handle the pitch and throw of a vessel underway. Flexible solar panels do not provide as much power and can become a hazard on a moving boat.

  • Panels take up valuable space on the deck and may be damaged by accidental tromping. Smaller units may not provide enough power for the ship's needs and must be sized appropriately for the intended load.

  • Connectors must be waterproof since the panels will be exposed to waves and rain. Adding an extra layer of plastic protection to the panels will reduce their already low efficiency.

  • If the panels will be exposed to salt water, stainless steel frames and connectors need to be used to avoid premature rusting.

  • Solar panels must be regularly cleaned of dust and water marks to retain maximum efficiency.

  • The charge controller, batteries and all connecting wires must not be exposed to water.



Benefits of Using Solar Power for Boats

Despite the disadvantages, the convenience of being self-sufficient while at sea may be worth the extra cost and effort. Some features and benefits include:

  • Quiet operation. On-board generators (and the extra fuel) may be eliminated. Solar power is pollution-free.

  • No moving parts. Unlike wind turbines, there is very little maintenance required. Only a periodic cleaning is needed.

  • Scalable power. Available units are 50 W, 75 W and higher. Boaters can start off with a small system and expand as demand and confidence in the technology increase.

  • No need to haul extra fuel for the motor or a portable generator.

  • Except for clouds, there are no overhead obstructions on the water to cast shadows on the panels.

  • Solar panels will continuously recharge the batteries, even when the boat is moored & unmanned. A charge controller will automatically disconnect the supply when the batteries are at full charge.

  • When mounting solar panels directly to the deck, the brackets need to be securely fastened and weatherized. Since the frame will be permanently secured to the hull, the bolts should be well caulked to prevent water ingress.

  • Rail-mounted panels can be removed and installed as needed. However, attaching these frames to a rail may make boat maneuvering a bit awkward, especially on a sail boat with a low boom. As a bonus though, these panels can be frequently tilted to remain perpendicular to the sun to produce maximum power output.

Sailboats: The large open deck of sail boats makes it an ideal location for solar panels. However, these units should be placed out of the way to avoid being damaged when crew members venture up to the bow. Even though the side of the hull is open, solar panels can easily get crushed by the dock, by other boats or by rough waves.

Solar power for boats is not just environmentally-friendly, but some people might also consider it a necessity when on the high seas. Having extra charge in the batteries to run electronics may be all that's needed to prevent a mishap (or recover from one) when away from shore. It's also an inexpensive and easy option for boaters wishing to overnight at distant shores or at unserviced docks.