solar panels?

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duetto
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solar panels?

Post by duetto »

hi all,

has anyone mounted solar panel(s) on mv? if so, i' appreciate a post with details.

we anchor out much of time and electrical power is borderline.
john & diane cummings
duetto mv34 #23
deising
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Re: solar panels?

Post by deising »

Diva Di hard solar panels 1 - Copy.jpg
I am going to post the details of our solar panel installation as requested by Mac Carter.

At first, I was intrigued by the setup used by another Powercat owner to mount semi-flexible panels (very inexpensive) to lightweight polycarbonate stiffening board and then secure to the aft Bimini. Unfortunately, the inevitable flexing in strong winds caused all 3 panels to go open-circuit just weeks after installation. That was an expensive mistake as I had also permanently ruined the Bimini to secure the panels.

So, I got a new Bimini made and went the tried and true path of SS tubing above the aft Bimini to mount 2 hard solar panels. I bought 2 180W (nominal 12V) monocrystalline panels by Solar Cynergy and mounted them with U-bolts to the tubing. Since I was using the wire (10 gauge) that the old panels used, it forced me to have the wire exposed on top of the Bimini for several feet. If I were doing it today, I would try to ensure the wire was enclosed within the zippered folds of the Bimini all the way. The tubing and hard panels add abouty 40 pounds of weight, but I consider that trade-off acceptable.

The panels are connected in series, which means that the wire is carrying at maximum 36V at 9A. The current stays the same as with 1 panel, but the voltage doubles. That allows for less voltage drop due to the lower current. I would pick a different controller if I were to do it again. I think m/v Gusto picked a good one (need to search here for that). I mounted my rather large Midnite Solar controller at the intersection of the overhead on the starboard side so I could can read the display standing forward of the lower helm.

By adding a shunt to the house battery wiring, my controller can act as a battery monitor (counting amp-hours in and out to give you a state of charge). That was one redeeming feature of my controller choice. I ran the wiring from the Bimini panels through the hole forward of the RADAR mast and through the wiring chase to the controller.

The output wires go down the chase to the electrical compartment, which is a real pain as you have to remove the overhead in the starboard stateroom to get access. The output wires terminate on the positive and negative busses. There is no need to go directly to the batteries, although you certainly could if you chose a different spot for your controller.

I am happy with the performance of the panels/controller. On a sunny day in winter, we can run the generator about 45 minutes in the morning to bring the batteries up from their -100Ah overnight to about 90% charge, and then the panels will carry all our daily loads plus bring the batteries to 100% before sunset. Our house bank has 4 T-145 wet-cell Trojans with 520Ah total capacity. I don't like to bring them down to less than 70% charge if I can help it. The lower you go, the more life expectancy you lose.

Once, on our recent cruise to Maine, the generator inlet got completely plugged with weeds and I could not get to somewhere where I could unclog it for several days. Having the solar panels sure helped with no generator, but I realize we could have just as easily had overcast conditions at that time and got no help from the panels.

I share these details, but I would not suggest trying to mimic my setup. I am only familiar with Heron's and Gusto's installations and I would look at those first.
MPPT controller - Copy.jpg
Duane Ising
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2006 PDQ MV 34 - hull 91, 75HP, 3-blade
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Re: solar panels?

Post by Expatriate »

Since I put a hardtop on the flybridge, I decided that I might as well cover it with solar panels. We have a 300 watt panel on the aft bimini, but is often shaded part of the day by the flybridge bimini. I put two 300 watt panels on the flybridge hardtop. I wired them in parallel, but I could have wired them in series for 72 volts and half as much current. The controller I picked is made by Victron. It will accept 100 volts and has WiFi. The company provides a free app for your phone or iPad. It tells you everything you might want to know about how the panel is charging the batteries. Of course, it does not tell you how much energy you are using. The existing controller on the aft panel had somehow been damaged, so I replaced it with a smaller Victron controller. I'm still at the dock, but I turned off the battery charger two months ago. My batteries are charged up each day by noon. The fridge is on all the time and we are there every day for various projects. Our power usage will increase when we head back to the Bahamas, but we are pretty confident.

Two panels and two charge controllers cost about $900. The panels have come down in price since I purchased them. They are made by Canadian Solar and now cost $201 each.

Tim
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Re: solar panels?

Post by Expatriate »

Just an update. We are in the Bahamas now. Battery chargers are in float mode (charged up) every day by about two PM. It has worked out nicely.
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Re: solar panels?

Post by Expatriate »

Just an update. We are in the Bahamas now. Battery chargers are in float mode (charged up) every day by about two PM. It has worked out nicely.
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Re: solar panels?

Post by Expatriate »

Sorry about the duplicate post. Slow response here.
deising
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Re: solar panels?

Post by deising »

Good news. It is hard to beat the quiet efficiency of a good solar panel installation.
Duane Ising
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Re: solar panels?

Post by boatpf »

Solar panel install sounds great!
Are you happy with the 2-300watt panels?
Anything you would do differently on your hardtop install or amount of solar power?
Any issues with drilling in the fiberglass hardtop to screw on panels?
Did you through bolt or just screw into fiberglass top ?
Also did you ever find a controller that will display usage/draw as well ?
Thanks
David
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Re: solar panels?

Post by Expatriate »

David,

The hard top has aluminum ribs across about every two feet. I drilled and tapped (threaded) into the ribs and screwed brackets made of 90 degree aluminum to the top and same thing to the panels. Did not thru-bolt and put sealer between the brackets and top. No problems, leaks, or regrets. I agree with previous post, higher voltage is better. My Victron controller will take 100 volts and put out 14.4. My panels are 36 volt nominal, about 40 volts open circuit. I could have run them in series for 72 volts, but did not want to push my luck.

Tim
M/V 068
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