In 2014 we kitted out JollyDogs with cruising gear, and we got our hands on 4 new 230 watt Sunpower solar panels. Sunpower dealers and installers weren’t allowed to sell them, but the economy had been tough on some small businesses and I found some on Craigslist. Same way I found the Xantrex pure sine 2000 watt inverter/charger. Brand spankin’ new and about 1/3rd the price of a retail unit. We spent about 5 months at Cruiseport marina in Ensenada, Mexico installing all kinds of new gizmos, and fortunately we got to do business with the best stainless steel fabricator in the area. When we were done we had 2 panels on the stern mounted over the dinghy davits and we had 2 panels over the soft cockpit tops, one each side. A single Morningstar MPPT60 solar controller managed the output from the four panels, wired in parallel. In sunny Mexico our 920 watts of solar power kept our LiFeP04 cells charged pretty well. However, Isabel warned me that where we wanted to cruise in the South Pacific there be clouds, and believe it or not, rain.
During our refit in 2018 I found a deal on some “never installed, no warranty” Sunpower panels from a salvage business. I took them out into the parking lot for a quick test, and they met or exceeded factory spec, so I took home 2 of the monstrous industrial size 470 watt panels and 2 of the 250 watt panels which were the same form factor as the 230-watt panels already installed over the soft cockpit tops. Bill Prokes, the best man from our wedding helped me fabricate extensions to the dinghy davits and a highly skilled Mexican welder in the yard helped by building sway supports in-situ to complete the structural installation. In the end we had an array of 1440 watts total spec output, each with its own Victron MPPT Smart controller.
Now we’re in French Polynesia not terribly far South of the equator where there are sunny days and days of blinding rain. On the brightest days with sun overhead, I’ve seen 115 amps output at 13.6 volts, well above factory spec power. On the most heavily overcast and rainy days I’ve seen less than 5 amps output at the same time of day. I’ve learned that really lousy solar conditions can turn solar equipment into “useless weight”, however those conditions are fairly rare. So now we have an optimally managed solar array, installed to minimize shading by bits of boat structure. Combined with 720 amp-hours of LiFeP04 battery power, we can generally get through a couple of miserable solar days without resorting to generating electricity with fossil fuel. However, I have been known to run the port engine to make a tank of hot water on 1 or 2 of those really gloomy days, as a hot shower on a chilly windy rainy 25 Celcius day cheers us both up. A 30-minute engine run will also net us about 60 amp-hours of charge, but that’s just a bonus.
We think the solar panel installation looks just fine on JollyDogs and doesn’t detract from her lines. Perhaps beauty is in the eye of the beholder, but what we don’t see is diesel jerry cans secured the length of the safety lines on both sides of the boat. Can’t say that for folks who have diesel generators as their primary charging source. We also don’t have gasoline cans all over the place, nor the safety risk created by storing and handling lots of gasoline on board like those folks who use the ubiquitous Honda EU2000i generators. We don’t have the maintenance hassles of keeping generators alive and we don’t have to listen to them run. We made a SWAP (size, weight and power) trade-off and went with solar, and the outcome has been very satisfying.
Don’t underestimate how much solar or battery capacity you should really install. Don’t cheap out on the controllers, and don’t do silly things like installing equipment that can cast shadows on your solar panels
You’re welcome.
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