Solar system install

L

localboy

New member
After being on the hook for three days, and having to start the engine every morning to charge the group 31 house battery, I finally thought about solar. RVs use them. Sailboats use them. Why not? After reading too many articles, blogs etc and watching hours of Youtube videos on the subject, we took the dive and I installed a simple solar system. Our main draw is the refrigerator (and the Eberspacher heater, but only in winter/fall, so it's not a real issue). Every light is LED and we have no other huge draws.

I'm starting with one flexible 100w solar panel and if it isn't sufficient, I can add another panel easily enough. The panel is not hard installed; I plan to put it out only when we need it, either on the roof or the Bimini-top. We probably will not make runs with it "up there", since the alternator is charging during that period. But to not have to run either the engine or gen-set, will be nice. Plus, it's "free" power...

Rich Solar 100 watt panel: $160 on Amazon
https://www.amazon.com/Bendable-Fle...ds=rich+solar&qid=1564272946&s=gateway&sr=8-9

Renogy "Adventurer" 30 watt controller: $40 on Amazon
https://www.amazon.com/dp/B015DDVDQS/ref=twister_B07BDDC7HY?_encoding=UTF8&psc=1

Rich Solar 10 gauge 20 foot cables w/ MC4 connectors: $27 Amazon
https://www.amazon.com/Richsolar-So...h+solar+wires&qid=1564273000&s=gateway&sr=8-3

15' of 10 gauge tinned marine 2 in 1 wire: $21 from Harbor Marine, Everett

Various connectors, fuse holders/fuses, nylon wire sleeves, hardware etc: ~$75

So for about $325, and perhaps 8 man-hours total, we have a system. Curious if it will "keep up" with the fridge, which is the only real energy hog on our boat. Pics in our album.
 
Our CD25 is set up to run the whole boat for a week or more at anchor. This includes our new more efficient Isotherm fridge, Engel freezer and Spectra watermaker, and everything else. I installed 2 Sunpower 110 watt semi-flexible panels permanently on the cabin top, a perfect fit, expensive but designed for salt water marine use. I fabricated aluminum brackets that attach to the radar arch and extend back over the bimini and just yesterday set up a removable 170 watt Sunpower panel (25% efficiency) that will only be put up on long cruises. The total watt potential is almost 400 and runs through a Morningstar 30 amp marine grade MPPT controller that can convert excess voltage into watts unlike conventional old style controllers. We have two deep cycle group 31 house batterys. We have used variations of this type of system in our last two boats in the Sea of Cortez and I have found with a little research solar systems are an easy install. We have also used moveable panels on one of our boats to add or subtract watts as needed. I put up a photo of the panel I put up yesterday in my Sierra album.
 
If possible you want to leave a little air space under the panels to keep them cooler (and more efficient) (for "local boy". Probably 200 watts is necessary to keep up with the refrigerator. But 100 will cut the engine run time down considerably. As the sun gets lower, there will be less solar energy up North--you are just beyond the "peak" now.
 
thataway":1vbhfuch said:
As the sun gets lower, there will be less solar energy up North--you are just beyond the "peak" now.
Click to expand...
That's correct, but the days are also longer farther north and that, apparently, makes a substantial difference. I attended a solar seminar at the Seattle boat show where the presenter claimed that the PNW yielded more solar watts for boaters, over the course of the summer months, than for those in the Bahamas. Of course the reverse would be true in the winter, but we (in the PNW) don't go boating then.
 
IME, a flexible solar panel means it's kind of bendy, but not something you can roll or fold up.

How are you going to store your solar panel when you are not using it?
 
ssobol, we just bought a Renogy 100 watt flexible solar panel. It is made of a very stiff and durable hard plastic. We store ours along the settee. It is stiff enough to lay on the port side and not fall over while being supported by the seat.

We have not used it yet, but I have a question to you brats that have experience or knowledge with solar panels. Should I install a charge controller on this panel before using it. I figure that it will only put out about 2 1/2 to 3 amps of power and was thinking that I did not need a charge controller. I don't want to damage the battery or the panel so I thought I would ask you C-Brats before using it.

Thanks. Gary.
 
Day Break, with that size panel (100) you do need to regulate it with a controller to protect your batteries from overcharging.
Bob is right about allowing airspace under the semi-flexible panels, excess heat can cause loss of efficiency. I siliconed small dot spacers under mine.
At first I was going to find a way to tie the large, removable 170 over the top of the bimini but as Sunbrella easily suffers from chafe problems it would have had to be removed each time we were underway. Semi-flexible panels are not as rugged as ridgid ones and I worried the it would be damaged by too much handling. That is why I mounted it on a thin aluminum sheet and bracket that can be added or removed easily extended back off the radar arch.
When we did our shakedown last April on lake Shasta we found that the 2 110 panels kept the fridge and electronics up but was borderline with the little freezer turned on during cloudy days.
Our last two solar supplied boat worked out so well that I am really excited to see how this one will work out down in Baja on our winter cruise.
 
pcg":3q7lz61e said:
thataway":3q7lz61e said:
As the sun gets lower, there will be less solar energy up North--you are just beyond the "peak" now.
Click to expand...
That's correct, but the days are also longer farther north and that, apparently, makes a substantial difference. I attended a solar seminar at the Seattle boat show where the presenter claimed that the PNW yielded more solar watts for boaters, over the course of the summer months, than for those in the Bahamas. Of course the reverse would be true in the winter, but we (in the PNW) don't go boating then.
Click to expand...

The physics, astronomy and geography suggest that this may not true. One factor is that as the angle of incidence is decreased (less than 90*) the panel is less efficient. .

The amount of solar radiation is measured by "Insolation" which is the incident solar radiation in watts/sq meter per day. . This depends of the position of the sun, which goes as far North as the tropic of Cancer (23.5*North). The attitude of Vancouver BC is about 49* N, and Nassau, Bahama, is about 25* North. So at astronomical noon, the sun is almost directly overhead at Nassau, but still at 25.5* South of being overhead at Summer Solstice. I added Juneau @ 58*N with even longer day. (June 21, 2019)

A panel facing Due South in watts/m2/day:

Vancouver.............Naseau....... Juneau
Jan:......1.1............ Jan 3.9....... 0.4
April:... 4.5............April 6.5
May...:..5.4............ May 6.9
June......5.9............ June.6.5......5.3
July.......6.0.............July 6.8........4.7
Aug.......5.2............ Aug 6.2
Sept...... 3.9............ Sept 5.5......2.5

Having spent time at both attitudes, it is my impression that Nassau has more sunny days (despite afternoon thunderstorms) than the PNW, for example Vancouver BC). The above figures do not take into account cloudy Skys, but do length of day.
 
DayBreak":2f7sg8js said:
Should I install a charge controller on this panel before using it. I figure that it will only put out about 2 1/2 to 3 amps of power and was thinking that I did not need a charge controller. I don't want to damage the battery or the panel so I thought I would ask you C-Brats before using it.

Thanks. Gary.
Click to expand...
Gary, I'm no expert by a long shot, but everything I read/watched said a controller is required. Due to variations in sunlight, panel efficiency, wire length/gauge etc, the power (voltage) the panels send to the controller varies. The controller monitors all this so you don't send too much voltage to damage the battery(ies). Conversely, it sends all it can to a battery that requires it, assuming the panel is providing enough volts/amps.

There are two popular "types" (I eliminated a shunt):
PWM (Pulse Width Modulated) simple, inexpensive and sufficient for small systems. I chose this, as the system now is only 100 watts and I don't foresee more than 150 more, should I need to add another panel.

Maximum power point tracking (MPPT) newer technology, more expensive but for larger systems, worth it.

https://www.elprocus.com/solar-charge-controller/

I placed a 10 amp fuse, in a MC4 fuse holder, from panel to controller and 30 amp fuses at each end of the controller to battery + wire.

Again, I am no expert. I read a lot, talked to some people that have installed simple systems and watched myriad videos (which honestly, became overwhelming & confusing, as there is lots of opposing opinions out there; Caveat emptor). As I stated, I'm hoping this will suffice for simplicity/cost. Time will tell.

ssobol":2f7sg8js said:
How are you going to store your solar panel when you are not using it?
Click to expand...

I'm hoping it will fit under our V-berth cushions. Haven't tried it yet. Seems to be the popular storage option on boats.
 
thataway":16qe4dp6 said:
If possible you want to leave a little air space under the panels to keep them cooler (and more efficient) (for "local boy". Probably 200 watts is necessary to keep up with the refrigerator. But 100 will cut the engine run time down considerably. As the sun gets lower, there will be less solar energy up North--you are just beyond the "peak" now.
Click to expand...

Dr Bob, I have read this, re: heat having an adverse effect on a panel's efficiency. Makes me wonder how panels work in say, Arizona.

As to my "plan", I prefer to have it on the Bimini (stern) and the wires are long enough. I'm going to try strong magnets to hold it in place there and we will remove it once we get under way. As to the power required, I'm trying to keep it at one panel but that may not suffice; our fridge is over 10 yrs old now, so probably not the most efficient model out there.
 
When I changed the first system on my sailboat from a PWM controller to the first generation MPPT controller I received a measurably increased output from my panels, a claimed 15%. Any panel with an open circuit voltage above about 20 volts should show an increase in watts output. Defanatly will have more output on panels 100 watts and above. Once you buy the controller ( marine grade with conformaly coated boards for salt water use) MPPT's give you free extra output. I like the ones with a small programmable readout screen that you can then monitor all aspects of your system and batterys.
Power on!
 
Thank you for the information and feedback. I just placed the order for a Renogy 10 amp controller for the 100 watt panel. I had a feeling it was the right thing to do. Glad I asked and so now I will sleep better. Thanks guys.
 
heat having an adverse effect on a panel's efficiency. Makes me wonder how panels work in say, Arizona.
Click to expand...
Yep, the air gap under the panel remains essential in any hot environment--there is cooling from the high temps reached on the solar panels surface. The air under allows it to be cooler and more efficient.

Yes a controller is essential in all but the smallest units--like a 5 to 10 watt unit which is a trickle charger.
 
ssobol":1qdteof2 said:
IME, a flexible solar panel means it's kind of bendy, but not something you can roll or fold up.

How are you going to store your solar panel when you are not using it?
Click to expand...

The bendy panels are usually called "semi-rigid" vs. Flexible.....
 
We strap our 100 watt flexible panel to the Bimini top using nylon straps attached to the corner grommets. When trailering we have found that it fits well in the head standing vertically against the back window. We unsnap one side of the privacy curtain, slide it in place and snap it back.
 
Micahbigsur@msn.com":141w1iqi said:
That is why I mounted it on a thin aluminum sheet and bracket that can be added or removed easily extended back off the radar arch.
When we did our shakedown last April on lake Shasta we found that the 2 110 panels kept the fridge and electronics up but was borderline with the little freezer turned on during cloudy days.
Our last two solar supplied boat worked out so well that I am really excited to see how this one will work out down in Baja on our winter cruise.
Click to expand...

Would love to see pictures of the mounting? Also the placement of the everything from Fridge to Controller to extra Batteries....etc.

Would love details on the Baja winter cruise...maybe not in 2019/2020 for us but some day :)
 
I am only using my phone to post, and apparently it can't post photos here but if you click on our "Sierra" album photos those will come up. I have an overall photo but next time down at the Marina I will take a up close photo of the extended panel. It is almost embarrassingly simple with no welding needed just some sheet, angle, u bolts and pop rivets. I upgraded from 1 group 27 house battery to 2 31's side by side up against the port transom, our boat is a 03 so it does not have the molded deck but an open gap above the deck all the way accross the back. My next project is to install a remote watering system as with Suzukis I can't use 0 maintenance glass mat batterys. I will put up a photo of that soon. On the fridge it is under the helm seat in the same place, I did have to enlarge the opening just a bit. The Isotherm cruise fridge is more efficient and slightly larger than the previous rv one. We bought one of the small Engel portable fridge/freezers that just fits into the portside cabinet inside the door, it is so small it is only really useful as a freezer. (2.5 amps per hour) we have had 2 larger ones on previous boats over the years and they have been exelent. Again I will add photos.
 
A word of caution: Reading on another forum about fires started by bendable solar panels on top of Bimini fabric tops. Most were limited to only the Bimini and extinguished before fully involved. However there have been some where the fire was out of control and the boat lost.

Several factors:
1. Allowing the panels to flex/bend, eventually causes breakdown of the matrix which the solar cell and the wiring connecting each cell to the other causes increased internal resistance. This causes more heat, and eventually to the point of combustion initially of the matrix, and extends to the fabric below.

2. Lack of ventilation accelerates the heat process.

Rigid frame also have had breakdown--especially in cheaper systems where aluminum wiring is used.
 
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