Solar panel wiring question

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Mike GB32

Senior Member
Joined
Oct 18, 2018
Messages
158
Location
USA
Vessel Name
Giddy II
Vessel Make
1974 Grand Banks 32
I've searched high and low for the answer to this question and found nothing. I'm hoping someone here can help.
I'm installing 340 watts of solar on the bimini. I know that I need to use MC4 connectors and PV cable from the panels.
My question is:could I run the PV cable to the interior of the boat, end at a terminal strip or junction box and then continue with marine duplex wire to the controller?
I'm thinking it would be easier to run the duplex wire through the boat instead of the heavier PV cables. I'll be using 10 gage wire to carry about 60 volts at 6 amps.
Is there an ABYC standard for this?
 
There's no reason you need to use PV cable at all for a low voltage solar install. In terms of ampacity and voltage drop, I determined my 410w panels were fine with 12ga (separate run for each panel as they each have their own controller). So I just ran 12/2 marine duplex to both panels from the controllers and crimped on MC4 connectors at the panel end (full power is just under 10 amps at 40 - 50 volts). The wire is rated for 600 volts, so no issue there.
 
I'm obviously not an expert. I just found this from a company called Coastal Climate Control:
"The wires or cable connecting solar panels to a controller should be dedicated solar products that are sunlight, UV, and ozone proof, rated for wet locations, and must have at least 19 copper conductors to be ABYC compliant."

https://www.coastalclimatecontrol.c... Systems - Planning and Installation V3.5.pdf

Seems like there is a standard for it but I can't find it.

I'm still searching...
 
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I'd run PV cable at least till you get inside. It seems to be much more UV resistant than marine duplex, which is really meant for indoors. Once inside, anything with a proper rating for the current.
 
Following. I also used marine duplex (8/2) direct to the MC4 panel connections. Honestly hadn't thought of the UV exposure; mostly inside or under the bimini but I wonder if a bit of conduit might be in order for the balance.
 
So far after 2 summers I've seen no noticable UV degradation to the outer jacket on the duplex cable I used. Ancor claims the jacket is UV resistant and it's suitable for wet locations and finely stranded. So I can't see a reason why it's not suitable.
 
Mike GB32 said:
I'm obviously not an expert. I just found this from a company called Coastal Climate Control:
"The wires or cable connecting solar panels to a controller should be dedicated solar products that are sunlight, UV, and ozone proof, rated for wet locations, and must have at least 19 copper conductors to be ABYC compliant."

https://www.coastalclimatecontrol.c... Systems - Planning and Installation V3.5.pdf

Seems like there is a standard for it but I can't find it.

I'm still searching...
Click to expand...

Sent you a pm
 
Well, FWIW, it seems there is no requirement to use PV cable. The ABYC requirement is to use marine wire. Not necessarily PV.
I'm thinking I will go ahead and use the marine PV for the exterior portion just for the extra protection. And then transition to marine duplex once inside. I'll use a terminal strip mounted in an electrical box because of the high voltage.
Thank-you to those who replied here.
 
Mike GB32 said:
Well, FWIW, it seems there is no requirement to use PV cable. The ABYC requirement is to use marine wire. Not necessarily PV.
I'm thinking I will go ahead and use the marine PV for the exterior portion just for the extra protection. And then transition to marine duplex once inside. I'll use a terminal strip mounted in an electrical box because of the high voltage.
Thank-you to those who replied here.
Click to expand...

You mention a electrical box. Are you referring to a breaker box? I just installed solar and I had the same question. I plan on putting a cover on the wires as they exit the panels to the mast. Not only for looks, but for UV protection. I am running them to a breaker box. Can't remember where I read it, but it was stated you need a means to turn off the power created by the panels. Not necessarily for breaker protection, but to be able to switch them off.
 
What I plan on doing is installing a terminal strip inside a plastic box https://www.trawlerforum.com/forums/attachment.php?attachmentid=132425&stc=1&d=1664317892
(with a cover) only because I can't find a suitable terminal strip with a cover. I don't want to leave the terminal strip exposed with 60 volts running through it. If you should know of something more appropriate please let me know.

For the breaker (actually its a disconnect), the way I understand it is- you need to break both positive and negative at the same time. I agree-not as thermal protection but as a way to disconnect the panels from the charge controller if needed. I got mine through Explorist.life.
https://shop.explorist.life/shop/all-products/switches-disconnects/solar-isolator-disconnect/
He has a great series of videos on solar power for campers. The tech is very similar.
 

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Mike GB32 said:
What I plan on doing is installing a terminal strip inside a plastic box https://www.trawlerforum.com/forums/attachment.php?attachmentid=132425&stc=1&d=1664317892
(with a cover) only because I can't find a suitable terminal strip with a cover. I don't want to leave the terminal strip exposed with 60 volts running through it. If you should know of something more appropriate please let me know.

For the breaker (actually its a disconnect), the way I understand it is- you need to break both positive and negative at the same time. I agree-not as thermal protection but as a way to disconnect the panels from the charge controller if needed. I got mine through Explorist.life.
https://shop.explorist.life/shop/all-products/switches-disconnects/solar-isolator-disconnect/
He has a great series of videos on solar power for campers. The tech is very similar.
Click to expand...

Instead of the exposed terminal strip, I am using a circuit breaker made to go inside a circuit breaker protection box. Smseace makes them and they are around $20 on amazon. Different sizes depending on how many panels you have. The circuit breaker I'm using (dc miniture circut breaker for solar panels) has a connection for positive and negative wires. Pos and neg come in the top and leave out the bottom.
https://m.media-amazon.com/images/I/41TIW79uJHL._AC_.jpg
https://www.amazon.com/gp/product/B0957BWHGD/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&th=1
 
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Hi Mike
Just completed the same job. Was thinking the same but turned out just get 1 pcs wire twice the length of the run. If the panels are installed in series cut the #10 pv wire in half. Factory male/female to the panels cut end to charge controller. Was easier to run 2 wires than 1 heavier duplex. Saves a connection too!!
 
DDW said:
I'd run PV cable at least till you get inside. It seems to be much more UV resistant than marine duplex, which is really meant for indoors. Once inside, anything with a proper rating for the current.
Click to expand...


+1
 
Note. For long distance it is best to run at higher voltage and lower amps, otherwise very heavy cable is required. It is best to locate the controllers with their DC output close to the batteries and connect with heavy gauge wire. You will know the wire is too small if it feels warm when carrying a load.
 
Hello Mike,


My winter project is installing solar panels on top of my GB32 bimini. I'm curious as to which panels you're using. I need to make mine easily removable as the bimini (and mast) comes down for boathouse moorage. I'm thinking 2 X 175 watt flexible panels.


Keijo
 
I went with two 170w Sunpower flexible panels.
So far the setup is working really well. I haven't tested the output but I can tell you that I can now run my refrigerator full time and the two 8D house bank batteries are at 100%.
I will be at the boat tomorrow and I could take a picture of the panels mounted if you like.
 
Keijo said:
Hello Mike,


My winter project is installing solar panels on top of my GB32 bimini. I'm curious as to which panels you're using. I need to make mine easily removable as the bimini (and mast) comes down for boathouse moorage. I'm thinking 2 X 175 watt flexible panels.


Keijo
Click to expand...

My installation is designed around the same necessary dropping of both mast and Bimini, in order to have sheltered storage. In my research, I was cautioned to avoid flexible panels, as they don't survive a lot of flex, so won't last if you are constantly removing them for storage, and they have less output per sqft than rigid panels. The net seemed to be quadrupling the cost, for similar output, and shorter life.
Rigid panels are still a possibility for you, because you have rails around your FB, and most of that space is away from the Bimini, so you won't have much loss due to shading.
Check out my installation here: https://www.trawlerforum.com/forums/s31/my-new-solar-system-44588.html
 
Keith,


There should be very little flexing in my planned installation - They would be stored flat and deployed after the bimini is raised and removed before the bimini is lowered. I have seen a few of these installations (including on an identical boat) and all are said to work well. I'm reserving the side rail mount option in case I need more panels. I use about 50-60 amps every 24 hours in the summer.
 
Keijo said:
Hello Mike,
My winter project is installing solar panels on top of my GB32 bimini. I'm curious as to which panels you're using. I need to make mine easily removable as the bimini (and mast) comes down for boathouse moorage. I'm thinking 2 X 175 watt flexible panels.
Keijo
Click to expand...

Pv panels have been on my list for awhile as well. I am going with Solbian flexible panels on top of the Bimini and Victron controllers. The cells are made by Sunpower and they are assembled by Solbian in Italy. I spent quite a bit of time poking around on the web and on Cruisers Forum to find out what the sailboat cruisers are using and Solbian came up fairly often as durable and good yield for a flex (thin/light weight) panel. It has been interesting learning about the topic over the past few weeks. Overall, lots of good options out there when it comes to solar.
 
I made a hard top replacing the Bimini, hurricane Ian wrecked it.

Now I'm reinstalling the Bimini frame.

using two aluminum 1 1/2 X 1 1/2 angle bolted to the frame running fore/aft
the bolts have 3/4" spacers or standoffs to kept the panels from rubbing the against the canvas.

next the two 260 watt panels slide between the two alum angles, and fastened.

It's a work in progress at the moment, I'll post pics when done
 
Keijo-
As promised, a couple of (up-side-down) pictures of my solar panel installation.
The panels are mounted over two bimini frame rails so I attached the panels to corrugated plastic first to support them and help dissipate heat.
There is velcro on both top and bottom of the perimeter flap. An idea I borrowed from Rod at MarineHowTo.
IMG_5183.jpg

IMG_5184.jpg
 
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Thanks, Mike. Any idea how many amps you get on an average day?
 
Keijo-
Here's a screen shot from the battery monitor. It's been mostly cloudy lately.
IMG_5188.jpg
 
Your install looks nice. Those numbers are better than I would have expected for a cloudy day. For your 340W rated system, what are you seeing on a sunny day?
 
Fletcher500- This is from yesterday. I had the boat out on the water for a while. I agree, it seems to be charging well.
IMG_5193.jpg
 
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