Installing solar panels

[John Langford]

I'm just finishing up a project that might interest other owners. I wanted a bit of protection from the sun while sailing and I also wanted to use solar power to keep up the batteries while cruising. So, instead of getting a professional to build me a Bimini and then putting expensive flexible solar panels on top of expensive Sunbrella cloth, I decided to build a smaller Bimini frame (two flat horizontal tubes instead of the normal three tubes with a curved crown) to support two 150 watt Renogy hard panels. As you can see from the Photo, I have left the Centre portion between the bridle wires open for the moment but may fill it with smoked plexiglass or even a piece on Sunbrella with a clear panel to allow me to see the sails. Since I spend most of my time when sailing sitting on the port or starboard coaming , I may end up doing nothing.

My Bimini frame attaches to the push pit rail just like a regular Catalina 34 Bimini frame. I needed two 20 ft lengths of polished 304 SS 1" .065 tubing for the two horizontal elements and the vertical stiffening on the port and starboard pushpit rails. Another 6 ft of tubing were required for the side-to-side stiffening visible just over the top of the green Sunbrella wheel cover in the photo. The structure is very rigid and there is minimal drag from the panels themselves. A local metal shop did the four bends. With the various fixed and hinged rail mounts, end cap fittings etc. The frame construction was around $600 Canadian. A local Bimini maker quoted around $3000 merely to build the frame. I can provide more details re the lengths of the horizontal and vertical sections and the stiffening elements etc if anyone is interested.

Because of the potential for shading (radar mast and dome, backstay bridle wires) I decided to use a separate Genasun 10 amp converter for each panel. Therefore, I led the package of four 10 gauge solar panel wires down the inside of my radar mast through the starboard lazarette locker under the reefer compressor and along the big PVC tube carrying the reefer lines forward to the evaporator. Not a process without moments of trauma. That PVC tube terminates in the space just above the aft starboard dinette seat where the batteries and water heater are located. I then led the wires down to the "Starboard" converter panel visible in the second photo.That photo shows the two Genasun converters, the two studs collecting the positive and negative output of the two converters and an on/off switch on the positive cable to the battery bank. The red 10 gauge wire is protected by a 30 amp cube breaker on the positive battery stud. That breaker also protects the positive wire from the 120v AC Xantrex battery charger.

Everything is up and running. I can't report reliably on results and performance as I turned on the system on December 21, the day with the least sun of the year and all of that at a very low angle through the rigging of other sailboats on my dock. The batteries were already fully charged so at this point my battery monitor tells me that all the batteries are asking for is a trickle charge to keep them at 13.50 volts or so. The experts say that on sunny days in the spring and summer I should expect to be able to easily replace the 60 amp hours I use in a normal 24 hours at anchor or sailing. We will see.

Everything include, this project cost around $1600 Canadian. The two panels were under $600 and the converters were $130 each.

Let me know if there are questions or suggestions.

[Jon W]

Hi John, I plan to do the same thing for the same reasons you describe. Nice job and it's nice to see an example. Thanks for posting it.

[Noah]

Nice install. I saw another approach to panel install that I thought was interesting. The boat RAN (Ransailing, a well followed youtuber) has two ridged panels mounted on lifelines that are (manually) adjustable to track sun angle. Not a bimini solution but something to consider. They swivel flat against lifelines/stanchions when not deployed. They have sailed from Sweden to Panama so far with this configuration. Don't know the (+/-) of it, but apparently it has worked so far for them, on a budget.

[John Langford]

I gave some thought to side mounting two panels. It would work but there are some negatives to consider. First, I couldn't see mounting more than a 50 watt panel on each side without extending beyond the stern or over the lifelines and interfering with the stern seats when horizontal. 100 watts wouldn't make a large dent in daily amp hour usage. Second, only one side could be oriented towards the sun unless it was directly overhead. Third, and perhaps most important, if you have a bimini or use some other form of cockpit sun cover at anchor, one or both of the panels  might be very shaded. Finally, heavy users suggest that constantly adjusting the panels becomes a drag. I opted for a 'fit I and forget it' approach with enough wattage hopefully to overcome shading and second best panel angles.

[Noah]

Good points. Their solution was just another way for a 40-footer with no bimini, plus they have a wind and towed turbine generator, as well. I like your fixed panel "leave and forget approach", too. I have rebelled  against getting a bimini, as they seem claustrophobic to me and kill the lines of the boat. Felt the same way about my dodger and was going to remove it when I bought the boat, until everyone got cold and wet and complained!

[bayates]

We installed our 2 100W panels into the bikini. The. Admiral sewed the Velcro on and it works great. Installing 3rd panel over the davits to give that little extra. 

[John Langford]

Brian, I would like to see a photo of the two panels sewed into a bikini. Or maybe not😬😬

An update on the solar panel project. I couldn't figure out why I was getting readings of 15 volts during the absorption charging phase and 14 volts during float phase. The controllers' advertised maximum values were 14.4 for absorption and 13.5 for float. A query to the very helpful Genasun tech support folks set me straight. The converters are temperature sensitive which is why Genasun recommends installing the converters in the same compartment as the batteries. The temp in my battery compartment in mid-winter is the same as the water in the chilly PNW, F46 degrees. The advertised values are for a battery at 75F. As the temp goes down the charging voltages go up. All I have to do is keep an eye on the water level in the 4 Trojan T105s.

With more and higher angle sunshine I have been running the fridge overnight and the panels are keeping up with the demand even on mixed sunny/cloudy days. It looks very promising for spring and summer.

[Jon W]

That's great news. Do you have a wiring schematic for your system that you can post with gauges, fuses, etc? Thanks for the help.

[John Langford]

Hi Jon
I don't have a schematic but if you have any questions about the setup after reading my account I would be happy to answer them.

[Jon W]

Ok a few questions, may have more later-

What is the voltage drop running 10 AWG from the panels to the controllers?

Why use a controller for each panel instead of combining all panels to one controller like a Blue Sea 3024i like Blackdragon did?

What is a "30 amp cube breaker on the positive side of the battery" Is that a 30 amp MRBF fuse, or an actual circuit breaker?

Is the switch to shut off the charge current from the Solar panels? Is it under the starboard salon seat?

Do you have a remote panel for status or do you rely on a battery monitor?

[DaveBMusik]

Ok a few questions, may have more later-

What is the voltage drop running 10 AWG from the panels to the controllers?

Why use a controller for each panel instead of combining all panels to one controller like a Blue Sea 3024i like Blackdragon did?

What is a "30 amp cube breaker on the positive side of the battery" Is that a 30 amp MRBF fuse, or an actual circuit breaker?

Is the switch to shut off the charge current from the Solar panels? Is it under the starboard salon seat?

Do you have a remote panel for status or do you rely on a battery monitor?

I also chose to put in two MPPT's (Blue Sky). My panels are canted a bit to each side with the contour of the bimini and I am always amazed at the difference in energy the two panels are putting out. My theory was, with limited real estate for mounting, I wanted the most efficiency possible. I use their iPN remote to monitor http://www.blueskyenergyinc.com/products/details/ipn_proremote

[John Langford]

I haven't kept all my worksheets but I needed 30 ft of 10 gauge cable (120 ft in total) to get to my controller panel  in the starboard battery locker. I have never seen less than 17 volts being delivered to the controllers measured with my multimeter at each controller.

Dave answered the question about using two controllers where shading or panel angle is an issue.

I am using a 30 amp Blue Sea MBRF terminal fuse block on the house battery bank.

The on/off switch on the controller panel is to turn off the solar panel current.

I do measurements using the battery e-meter and a multi meter to check accuracy and test input and output at the controller

Hope that helps

[Mick Laver]

Not to get too off-topic, but I'm also considering a bimini (or bikini - don't you love auto-correct?) solar panel installation but I don't necessarily want the panels up all the time. The clean solution would seem to be to plug the panels into bulkhead connectors such as those offered by Solbian (https://www.solbian.eu/en/electrical-connections-and-accessories/53-deck-seals.html). However, given the options for mounting locations I think these wouldn't survive getting kicked or sat upon or having lines drug over. I'm looking for something a bit more robust, and it seems any 2-pin bulkhead connector of sufficient gauge would do the trick. Any experience or suggestions? Thanks.

[Paulus]

Mick, you might go back(4yrs) on this message board and look at the pic of my solar panel on top of the bimini.  This May will be the beginning of my 5th. year.  My panel, not the bimini stay up year around. Most people do not realize that I have a solar panel, it is out of the way and it has stood up to some very robust sailing conditions.
Paul

[John Langford]

Mick
One option might be to lead the solar panel wires through the starboard ventilation hose clamshell (or a smaller dedicated clamshell vent) to a bus bar in the starboard lazarette close by the reefer. Then you could just detach the wires from the bus bar, pull them out and take the solar panel away.