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Boats Shade straddles two panels (only 1 panel working): 9.5 amps. Credit: Road Less Traveled

Published on May 11th, 2013 | by Nicholas Brown

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Solar Power Installation On Sailboat “Groovy”

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May 11th, 2013 by
 
A sailboat named Groovy has been equipped with a solar power system that powers the boat’s refrigerator, freezer, laptops, a 22″ TV, a stereo, and more. And this isn’t the couple’s first solar-powered mobile home.

“My husband and I have been traveling full-time by sailboat and RV for the past 6 years, and we have lived entirely off of solar power in our trailer and sailboat,” Emily Fagan wrote in a message in CleanTechnica‘s Solar Energy Google+ community. Emily and her husband lived in two solar-powered RVs before the sailboat. Now that they live in the sailboat, Emily writes, “we haven’t plugged in to shore power since September, 2011.”

Solar-powered sailboat

Hunter 44DS Sailboat.
Image Credit: Roadslesstraveled.us

Groovy is a Hunter 44DS sailboat. It is equipped with the following:

  1. Three 185 watt, 24 volt Kyocera solar panels, totaling 555 watts. These are wired in parallel to avoid the impact that shading has on the solar panels. Great idea for this boat, which is shaded by a mast!
  2. Combiner box: This connects the three solar panels’s wires to one charge controller.
  3. A Xantrex 60 amp MPPT charge controller.
  4. A 600 watt pure sine wave inverter. Pure sine wave inverters are the best and can successfully power everything, including refrigerators, fans, air conditioners, and other items which rely on AC-powered electric motors. The other common type of inverter (modified sine wave) doesn’t work well for these appliances. When using DC refrigerators, this problem vanishes, as no inverter is needed.
  5. A Xantrex 2,500 watt modified sine wave inverter/charger.
  6. Mastervolt AGM 4D batteries, (1) Group 27 AGM battery (710 amp-hours)
Image Credit: Road Less Travelled

Image Credit: Road Less Traveled

While the application is fairly unique, this article is relevant to most people interested in solar power because it specifies important facts that you should know before setting up a solar panel system.

The first fact to know is that the slightest bit of shading significantly affects the power output of solar panels, especially if your solar panels are wired “in series.” The solution is to wire them “in parallel” and, of course, to try to make sure your panels get shaded as infrequently as possible. (On a home, this is done by putting the panels where there isn’t any shade from trees or other objects.)

Since this solar setup is for a boat project, there is the possibility of shading caused by the mast and other parts above the solar panel, so the owners were happy they had learned that lesson from their solar RV projects, but Emily and her husband Mark were still shocked at how much shading affects solar output. There’s a section all about this in their article about the boat.

Full sun & no shade (3 panels working): 22.5 amps. Credit: Road Less Traveled

Full sun & no shade (3 panels working): 22.5 amps. Credit: Road Less Traveled

One panel partially shaded (2 panels working): 15 amps. Credit: Road Less Traveled

One panel partially shaded (2 panels working): 15 amps. Credit: Road Less Traveled

Shade straddles two panels (only 1 panel working): 9.5 amps. Credit: Road Less Traveled

Shade straddles two panels (only 1 panel working): 9.5 amps. Credit: Road Less Traveled

And, if you’d like a full rundown of how to set up solar in an ideal way on an RV or boat, they also have a multi-part Solar Installation Tutorial for RVers and sailors.


Groovy Notes

Mark and Emily added several notes about the project, as well as a ton of pictures. Some of the notes are below.

(1) Our odd collection of panels on the Hitchhiker was due to the Kyocera 130 panels not being available at the time of our installation (we brought one over from the Lynx).  (2) Our switch from the Outback to the Xantrex charge controllers between the Hitchhiker and the boat was due to the Xantrex being cooled by non-moving fins rather than a fan. In hindsight I would probably use the Outback charge controller in the future only because it displays more information on its screen rather than having to scroll through multiple screens to get the voltage, amperage, watts and charging stage.  (3) Our Group 27 start battery on the boat is isolated from the set of 4D house batteries only when the voltage of the bank drops too low.

Combined, the DC refrigerator and DC freezer draw about 100 to 120 Ah (Amp-hours) of current per day. Solar panels generate DC, and batteries supply DC as well. DC refrigerators can be powered without inverters for this reason. This can save plenty of money, which is why solar lights always contain DC LEDs.

Assuming this is a 24 volt system, the refrigerators consume 2.4 kWh to 3.1 kWh per day. (To calculate power consumption in Wh, multiple the voltage by Ah figure.)

In full sunlight, the solar panels generate 22.5 amps. When one panel was partly shaded, they generated 15.5 amps, and when two panels were slightly shaded, they generated 9.5 amps. In the winter, the system generated about 170 amp-hours a day, while it generated about 250 amp-hours a day in summer. With a typical daily amperage use of about 180–250, the duo concluded in retrospect that they should have gone with a more powerful setup.

“In December, around the winter solstice, on the southern mainland of Mexico (Zihuatanejo) our solar setup collected about 170 amp-hours per day. In June, around the summer solstice, in the middle of the Sea of Cortez (San Carlos) our solar setup collected about 250 amp-hours per day. In hindsight, it would be nice to have at least 750 watts of solar power to meet our power demands in winter.”

Again, to check out a lot more about this project, head on over to Road Less Traveled.

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About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is: Kompulsa.com.



  • http://twitter.com/eurolinesolar Chris Aloise

    To eliminate the “auxiliary sails”, you can also use a semi-flexible panel like the ApolloFLEX Mono that get glued down on the decks.

  • Mark W

    This is good off grid system which can apply to homes as well.

  • Bob_Wallace

    Using individual panel inverters would help a lot with shading problems. And shading is a real problem on sail boats.

    Many of us were using solar panels on our cruising sailboats 20+ years ago. Not to run refers, at $12+/watt solar was too expensive for that.

    (Having all those panels mounted up there as “auxiliary sails” looks really scary to me. Perhaps these people have never been in heavy weather.)

    • C02 up

      Hay Bob solar is not working Oceanography California measurements showing atmospheric carbon dioxide at 400.08 ppm under the CSI did not work.

  • Alicia Cox
  • RobS

    Umm, there’s pretty much not a sailboat around that does NOT have 2-3 solar panels to run the navs, electric refrigeration and entertainment systems. This has been entirely routine for about 10 years now, the alternative is diesel generated power and at marine diesel costs that comes to about $1/kwh which meant solar was competitive from very early on.

    Marine systems have been proving the potential of off grid solar for years now, I cant see anything about the boat discussed in this article that is even vaguely unusual.

    • Ronald Brak

      True, but still of some interest to landlubbers. Mind you, my father was a sailor. He used to travel from port to port, eating spinich and getting into stupid fights.

      • Bob_Wallace

        Have you had a DNA test? Ol’ Bluto got some Olive action from time to time….

        • Tina

          If a boat can setup an off grid system, why then are we
          spending on grid rooftop solar power
          system which has not reduced C02 emissions in the world .

        • Ronald Brak

          Tell me about it. My father was constantly beating off Bluto. If either one of them got their hands on Olive Oil it was on. It could take a dozen men to pry them apart.

          • Bob_Wallace

            Your father did what to Bluto?

          • Ronald Brak

            Everything.

          • Bob_Wallace

            We only got the G-rated stuff in our comic books….

          • http://zacharyshahan.com/ Zachary Shahan

            Oh my…

          • Bob_Wallace

            Are the boy-children getting a bit out of hand?

  • Elias

    Check out this ingenious electric engine for sailboats that can also be used to recharge batteries:

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