P42 Bimini/Dodger Upgrade to Solar

[HandsOnTech]

Sunrise was at 7:30. Slightly later on the boat due to trees and buildings.

The Victron controller does not begin charging until the panel voltage exceeds the battery voltage by 5V. There is a YouTube video explaining the efficiency reasoning, however, it does not explain why it is still showing a bulk charge rate of 0.1A in the evening. Besides being functionally pointless, it probably throws off the ‘total hours’ statistic.

I believe the three spikes at start-up is the MPPT program testing for optimum current/voltage from the panels.

 

[HandsOnTech]

How a nerd sees clouds:

 

[HandsOnTech]

Here is the almost final version. The only thing left to do is shorten the fwd/aft length of the frame to close the gap. I have not fully tied down the wiring because I want to collect some data with all six in parallel and then see if there is a difference in wiring the fwd/aft pairs in series.

So far, 72 hours away from the dock with hot water, microwave, and fridge freezer and there has been no need for the generator.

 

[DArcy]

Holey cow that's a lot of power
I am happy with my tiny little 250W of solar panels
Looks like a nice install.

 

[HandsOnTech]

Holey cow that's a lot of power
I am happy with my tiny little 250W of solar panels
Looks like a nice install.

Thank you. My original intention was to mount four 150 watt panels to the outside of the frame. When I researched what material I would use to fill the center, I concluded it was easiest to do a few mouse clicks on Amazon to order two more panels, open the boxes and insert eight clamps and nuts and bolts. Done. I used weather stripping from Lowe’s between the panels. I used the same weatherstripping on my forward hatch after getting tired of trying to source the original seal.

 

[HandsOnTech]

Some additional notes:
I used light anodized 7/8” aluminum tube as my prototyping material. It was a good choice, given the price difference to stainless, but it is not doing well in the salt marine environment. The finish is marred everywhere that a fitting has been. I will be replacing the tubes as needed with stainless. I am still in the process of snipping off an inch or two here and there to get it just right.

An excellent investment was the Ridgid stainless tube cutter on Amazon for about $42. It lets me make accurate cuts with no burrs on the outside and I was able to salvage and reuse several pieces of the original stainless tube.

The 7 foot lateral supports at the center were sagging slightly under the weight of the panels (~25lb each). A local bimini shop curved them for me for $10 each. I asked for a 4 inch clearance at the center when both ends are on the ground. This solved the problem nicely. When installing, first place the curved tube on the ground and make a mark to show where the ‘bottom’ is. Comes in handy later, especially when installing single handed.

 

[HandsOnTech]

Update:
First serious sea trial was crossing to the Bahamas. Everything held up well. The crossing was smooth with negligible wind, to the point that the moon’s reflection on the glass-like surface of the ocean was blinding. The only incident was a near collision with an anchored sailboat. My 20 minute alarm went off and I opened my eyes to see the boat’s anchor light dead ahead. Thinking quickly, I disengaged the autopilot and swerved to port, narrowly avoiding a collision. Only then did I have time to process the question of why a sailboat would be anchored in 2500 feet of ocean. I believe that was Venus rising in the east.

The only observation is that the SS/rubber clamps shown in an earlier picture to attach the 7/8” tube to the arch tube are not as sturdy as they look. Because the clamp sizes I chose match the tube sizes, there is not much room for tightening the clamp. The first night on the Bahama Bank the wind seriously picked up and with spray and severe roll the clamps began to slide from side to side. No damage, just disconcerting to hear. I will have to come up with a sturdier attach method between the tubes.

At the dock in Florida, 2 kilowatt hours per day from the panels translated to about $0.25 from the power utility. Pulling up to the dock in the Bahamas, the ROI meter kicked into high gear. Water was $0.50 per gallon and electricity was $0.60 per kWh. This was the first time I had pulled up to a dock and said “no, thank you “ to water and electricity. The Pur-80 water maker had been producing about 24 gallons per day on sunny days. Even with making and heating water, my power usage was below what the panels were producing.