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Once the generator project was finished, I was able to tackle the installation of the solar panels. Back in October we’d purchased (4) 113w semi-flexible solar panels from Aurinco at the Annapolis Boat Show. We opted for the thin flexible type so we could still use the hard-top above the cockpit as a sundeck and diving board.

The panels were backordered, so we didn’t get them in the mail until mid-January. As is typical on a boat project, there was a little bit of project creep. As I was measuring up the hard-top to figure out where to put the panels, I noticed a crack in the gelcoat that had allowed water to seep in and rot some of the wood between the layers of fiberglass.

I can’t readily explain to you how much I’ve learned in the last two months. I’ve always heard about this magical “epoxy” stuff that boats are built with, but I’ve never used it myself until December when we were building a battery box.

As goes that old saying about how a hammer sees everything as a nail, I’ve been looking all around the boat figuring out what I can fix with epoxy. This stuff is amazing, and pretty easy to use once you get the hang of it. The base of the hole thing is literally as easy as 1 pump of liquid from the can of “resin” and another pump from the can of “hardener”.

But back to the solar panels. I decided the best way to attach them to the roof would be with 6 screws per panel and a dose of the butyl tape recommended by this guy in Maine who really knows his stuff.

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The roof appears to essentially be a giant piece of balsa wood with a layer of fiberglass on the top and on the bottom. So I started drilling holes in the roof where the screws would go. I over drilled the holes so I could fill them with epoxy. That way, when I installed the screws, the screws wouldn’t be touching any wood that could then get wet and rot…it would be surrounded by rot-proof epoxy.

In the gallery, you’ll also see where I drilled a bunch of holes in the area where the wood was already rotten because of that gelcoat crack I mentioned earlier. It hadn’t gotten so bad that it was a dreaded “soft spot”, but I’m sure that would have happened eventually if left unchecked. Using a syringe I filled all the holes with thickened epoxy. After the first batch of epoxy dried, I mixed in some “fairing filler” (a maroon colored powder) to a peanut butter consistency to make the cured epoxy easy to sand flush with the rest of the deck.

Then I added a touch of white paint to make the changes blend in, even though all the holes will be covered with the solar panels anyway.

On the electrical side, I drilled a 7/8″ hole for the electrical leads to go through the roof. I then wired the panels so the both port panels were wired in series, then both starboard panels were wired in series. I then wired both pairs in parallel.

The panels output somewhere around 17 volts each, so by wiring each side in series, the voltage jumps up to 35v, but the amperage stays the same. This helps because I don’t have to use giant wire. 8awg wire is the largest wire I could run from the roof into the boat, so upping the voltage to 35v helps prevent too much resistance and power loss.

That’s what I understand from the people who know these things, anyway.

On the inside of the boat, the wires run to a breaker, then a Morningstar Tristar MPPT 60 amp controller that has a fancy readout to tell me exactly what the panels are doing and how much power the batteries are receiving from them.

From the controller, there’s another breaker, then a 2awg wire run to the batteries.

Final result? 4 panels screwed into the fiberglass hard-top that should be solid and rot-free for years and years to come and a fancy controller that will satisfy my dorky desire to know how many amp hours we’re sucking in on the daily. Based on the first two semi-sunny days that I monitored, we were averaging 75ah received from the panels per day.

Want to see a video of the installation? [Click Here]