Boat Project Solar Panels

Throwback Thursday: Solar Panels

Thursday, June 19, 2014S.V. CAMBRIA

Throwing it back to April 21, 2013, this blog entry goes over the costs and benefits of adding a solar panel array in the Pacific Northwest.

From April 2010, the newly installed side panels (with Sally photobombing off the stern)
If anyone tries to tell you that investing in solar panels in the Pacific Northwest is a waste of money, like they did us, they're wrong.  And we can prove it.

Three years ago we added a solar panel array and have been tracking the benefits ever since.  At the time, we only carried a single 32 watt panel (original to the boat and dating back to 1999) on top of our radar arch which put out a whopping 2 amps, if that.  Basically . . . a trickler.  Along with our wind generator, which is quiet but equally as ineffective, we could hardly call ourselves self-sufficient. 

Since the early 2000s, the price of solar panels has been decreasing at the same time the technology has been on the rise, along with fuel prices.  So the timing was ideal for making a change.  After (what seemed like) months of research, we purchased three Kyocera 135 watt panels measuring 60 by 26 inches and weighing approximately 30 pounds.  Needless to say, this required a bit of reconfiguring. 

The dodger and bimini on Cambria are canvas and would have required substantial stainless work to accommodate the weight of the panels, one of which would have been shaded by the boom most of the day.  In lower latitudes, shading wouldn’t make such a big impact; but here where the sun is at a 30° angle in the height of summer and approximately 65° in the winter, it does.  So we opted for the easier and (in our opinion) more practical installation and changed out two sections of lifelines (port and starboard) for a solid stainless bar which the panels are mounted on.  When conditions are rough, they lie flat.  But at other times of the day, we’re able to adjust them with several different props to maximize their output. 

Mounting the starboard side panel.
To control the system, we chose a Xantrex 60 amp MPPT with a battery temperature sensor, not because it was our first choice or that our system required the capacity (it’s much bigger than we need and has the ability to add other panels later on).  But because the company manufacturing the one we had originally wanted (a Morningstar 45) was experiencing difficulties sourcing components from their Chinese suppliers.  In the end, we were glad for the change and are very happy with the Xantrax’s performance.

Using the specifications provided by Kyocera, under optimal conditions the panels should generate 120 amp hours of power – 30 amps shy of our average daily consumption.  But we generally see more than that.  During the summer months, they produce 140 to 150 amps, with approximately 15 to 20 amps coming in during the peak hours (noon to four).  On our best day, we banked 172 amp hours and on our worst day, none at all.  But more important than the numbers, we’re not burning fossil fuels to compensate for our desire to watch movies or use the computer.  And equally as important, David’s now a free man and no longer held captive by the boat hour after hour in order to recharge the batteries – most days, the panels do the work for him.

We estimated that we’d recoup the cost of the system after three years, but our expectations were, once again, surpassed.  By the middle of last season, the savings on fuel surpassed the price tag and we’ve been living free (give or take) since then.  One of the greatest expenses to recover was the MPPT, with the materials for mounting coming in a close second.  The panels themselves were the least expensive components, costing around $330 a piece.

David has a meticulous personality and has been tracking their performance for the past three years:  Over the period, they produced a total of 35,815 amp hours (482 kWh).  To date, we estimate that we saved over 900 hours of engine/generator use and approximately 850 gallons of fuel – a monetary savings of $4000.  An excellent investment . . . for the boat as well as the environment.

* Looking at the three graphs, you can clearly point out the days when it rained . . . particularly late in the season.  The mid-range days were generally ones in which we were moving.

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  1. Thanks for this post. I am researching solar panels for our new yacht. We were thinking of getting a frame over the transom to mount them to - but having them on the life lines like you have looks great. Do you find they get in the way at all there?
    Love following your blog!
    Cheers Viki

    1. No. We really like having them on the side rails (which we had to install) because they don't see as much shade from the boom there and we can adjust them through out the day to make the most out of the sun. I just realized I didn't include a photo of the props we use to hold them out. Basically, we use a metal rod that inserts into a holder mounted on the lashing board and one on a support rail that we added to the panel to hold it out. We have 3 different lengths so the panel can either lie flat, at a 45 degree angle to the sun or at 135 degrees. So far, it's been working really well.

  2. Love seeing these kinds of details. We have solar panels on Galapagos but they are old and probably do not work. We'll be replacing them with new ones. Ours are mounted on top of the hard dodger. I'll bookmark this post for reference later.

    1. David did the research a few years ago and things have changed a bit; but if you want his notes, let me know and I'll email them to you. We're probably going to add one more panel to the array over the winter. We installed a portable freezer this year and the panels can only keep up with our energy demands on a sunny day. We're pretty greedy though and use about 150 to 175 amps in a 24 hour period.

  3. It is really interesting and fun to watch the process............... solar panels cost

  4. I really like the information provided in this article. And I really like the way you have explained each and everything so well. Very well done with the article. thanks

    1. You're welcome and thank you for taking the time to read the post! We really do appreciate it.

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