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Case Study: Time to Go Solar by Ed Eisen

Time to Go Solar

by Ed Eisen

It's midsummer. We're at our favorite anchorage, and it's another perfect day on the water. What makes it even better, is waking to the smell of coffee my wife started a few minutes ago. I crawl out of bed and slither up to the cockpit, cup in hand. What a view. We can see the mainland and a few boats throwing spray on a glassy blue ocean. Just as I raise my cup I think, “Damn, I forgot to start the generator.” The ole Honda 2000 is fairly quiet, but it is still not my favorite sound as I enjoy the morning. The other time I have to hear the generator is when the sun has transited to the other side of the boat, and I'm ready for happy hour. We bought the Honda when they were all the rage, and it has been a wonderful alternative to charging with the boat's diesel for the last ten years. Lately, I have felt a growing envy of my fellow boaters with solar power. So, after our typical family debate on cost versus benefits, my wife and I decided to add solar and more silence to our 2005, 43 foot Jeanneau.

We started from scratch and spent many hours studying the concepts and equipment necessary. We are far from solar experts, rather just retired boat owners who wanted a quiet way to charge batteries. If you are a first time, solar-do-it-yourselfer like us, I hope this short story of our installation will be of interest.

Sizing the system

While at the San Diego Boat Show, we visited the Sun Powered Yachts booth. We learned about their panels and reviewed a list of possible power requirements on our boat to determine how much solar wattage we needed. For us, the big items are the refrigerator and freezer. We use the freezer more as a beverage cooler, still two refrigeration units are the biggest draw on our boat. All lights are LED's so not much draw there. The other considerations were that we had easy space for two panels on our bimini and two were all we had budgeted for. With little more thought to sizing, we purchased 2x SunPower 110 Watt panels that we were optimistic would satisfy our needs.

Acquiring parts and a plan

The panels were our major single purchase, but we soon realized much more is needed to complete an installation.

1. How will the panels fasten to the bimini?

2. How to position the panels?

3. Will they connect in series or in parallel?

4. What size wire do I use