Author Topic: Solar panel arrangements  (Read 543 times)

Jackrabbit

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Solar panel arrangements
« on: October 18, 2019, 03:34:13 PM »
Hi folks

I thought it might be interesting to compare notes on solar panel installations for A32s - my wife and I installed two flexible 65 W panels on our bimini - feeding into two 110 Ah 1V AGM batteries connected in parallel - and would be interested in seeing ideas for adding an additional hard panel, say, 180 W.   I have ideas, but would like to see what others have done to get an impression of how the boat's appearance would be affected. Does anybody have photos of their installation they'd like to share?

Holdech

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Re: Solar panel arrangements
« Reply #1 on: October 20, 2019, 10:32:24 AM »
We completely rebuilt our DC system this year in readiness for a long trip south in the near future.

I'll give a quick "brain dump" and if you have questions or want more pics just let me know (curious, where are you located).

After doing an energy audit we went with 300 amp capacity true deep-cycle flooded batteries. The difference in longevity, as well as charge acceptance over "group" batteries (six times CA), is phenomenal. But you do need to adjust your charger to the correct charging voltage which is much higher than group batteries.

Monitoring is via a Balmar SG200. The Balmar is the ONLY monitor that gives true SOC and SOH continuously through the entire battery lifespan, at any temperature and even during the charge cycle.

A 100 amp Balmar alternator and external regulator provide charging while the engine is running. This puts a continuous 80 amps into the house bank until about 97% SOC before it tapers off.

For solar we did not want semi-flexible. I have spent several thousand dollars over the past few years with disappointing results. They integrate well with the boat (we also do not want to turn our A32 into a "sputnik") but they are not designed for repeated flexing - even a little. Yes, there are many people that have had no problems. Me, I've had five panels die. Two of them shorted and melted holes right through the panel and backing! I tried backing with a corrugated Lexan material but the end result was not much lighter than a rigid panel.

So we went with rigid panels. Three 100 watt panels fit over the back half of the bimini and around the split backstay. I came up with a design that extended the bimini frame with minimal added tubing. I also strengthened the bimini considerably with added supports to the stern railing. It still takes a lot of tubing and fittings. If you are close to Hamilton Ontario get everything from Brewers. They supply just about every chandlery around Lake Ontario. Tubing was one third the best price I could find anywhere else and fittings wer less than half. Saved a ton of money. I

Panels are series-connected which lets me use smaller gauge wiring back to the controller. With most panels you do need to make a small modification to prevent one shaded panel from wiping out the entire array's output. This entails adding a bypass diode (Shottkey type) across the panel output. Many panels still have a blocking diode that can be removed. These are only needed if you do not use a controller and cause about a 4% reduction in energy. I did all this in the connection box on each panel.

The solar controller is a couple-year-old Epsolar MPPT unit. It's fully encapsulated into a huge heatsink case and can be mounted anywhere (it's designed for outdoor use). It has a remote display at the nav station.

We used the system heavily this summer as we were without power for half the season, due to the high water levels. We also went on a six-week cruise where we were only plugged in once. On a sunny day, the house bank was back at 100% before noon and if overcast, by 2 or 3 in the afternoon.

Very happy with both the way it looks and how it performs.

Chris
Chris, Teliki, A32

Jeff.

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Re: Solar panel arrangements
« Reply #2 on: October 20, 2019, 03:07:06 PM »
We added three 100W semi flexible panels onto our Bimini.
Notice the bolt rope and track method of installation.
I went with semi flexible primarily due to their low weight. We wanted to attach them directly to the bimini.

I installed a victron smart solar controller and a BMV battery monitor. These have pros and cons. The best feature is the Bluetooth capabilities and the useful smartphone app. Your can change many settings and monitor the charge real time.
I'm not a fan of the victron charging algorithm, it's different than every one else's and has some issues.
I feel the ease of use and monitoring with these two Bluetooth devices and the victron connect app outweigh the cons. The company also updates and improves the products frequently. They appear to listen to user feedback.

If I had to start over I would consider rigid panels. With the curved shape of the bimini I rarely got close to full output. I feel that flat panels would yeild a higher average output.
Longevity is another consideration. The centre tube of the bimini structure created a pressure point and has started cracking the side of one panel.

That's all I have for now
Jeff
Aloha 32 Elixir V

Jackrabbit

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Re: Solar panel arrangements
« Reply #3 on: October 20, 2019, 07:01:56 PM »
Wow!  Lots of great ideas here.  I get the feeling that my flexible panels may not be long for this world, and when they do go I would go for adding a ss tube arch over the bimini and installing rigid panels.  We sail "Escapade" out of Bath (just West of Kingston), and I am thinking of eventually switching her to a wet mooring at Prinyers Cove, where electrical self-sufficiency would be paramount.

Burton
S.V. Escapade (A32)

Holdech

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Re: Solar panel arrangements
« Reply #4 on: October 20, 2019, 08:30:38 PM »
Friends of ours just bought an Ontario 38 that’s at Bath.
We were by this summer on our way to CORK in Kingston. Took a swing through Prinyers - there was an A32 on a mooring near the entrance to the cove. Lots of mooring balls there.

Oh and I should mention there are two other A32’s (both with solar) at our club in Scarborough. Not too long of a drive next season if you want to check them (and ours) out.

Chris
Chris, Teliki, A32

Jackrabbit

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Re: Solar panel arrangements
« Reply #5 on: October 21, 2019, 08:51:38 AM »
Might take you up on that, thanks.  Our friends at Prinyers often mistake the other A32 (a permanent resident of the cove) for us, as we like anchoring near her when we're there. 

Burton
S.V. "Escapade" (A3)

Jackrabbit

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Re: Solar panel arrangements
« Reply #6 on: October 21, 2019, 09:07:54 AM »
I've recently been told that mounting flexible panels directly on the bimini's Sunbrella can result in overheating due to lack of circulation underneath.  Mind, so far I've got two Summers in with them like that and no problems yet.   I do find that the way the wires are attached to the panels is quite flimsy, and I always worry they will come apart when I install and remove the panels each year, as there is a lot of torsioning of the wires involved in fishing them through the Sunbrella "frame" openings on the bimini top.  Can't think of the brand offhand, but it is the "kit" sold by Marine Outfitters which also includes the MPPT controller.  In any event, I wish I had gone with hard panels.  Building a stainless tubing mounting frame on the bimini would probably not be much more work than what my wife had to undertake in making the Sunbrella "frame" and bimini attachments (she followed the instructions provided in a Sailrite video).

Burton
S.V. "Escapade" (A32)

Bill Hutton

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Re: Solar panel arrangements
« Reply #7 on: October 21, 2019, 09:12:01 AM »
We have two 100W flexible panels but I added a pine frame around the border to give them more rigidity.  In the picture you'll see what they looked like without the frame.I think 200W is fine for a Canadian summer but wouldn't be enough down South in the winter months. But it will all depend on your needs and the efficiency of your fridge.
Bill Hutton

Bruce

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Re: Solar panel arrangements
« Reply #8 on: October 21, 2019, 10:42:30 AM »
I bought a system from Custom Marine Products ( check out WWW) which puts a rigid panel on a pole that can be swiveled and angled to follow the sun either on the anchor or while sailing.  I mounted in near the stern rail so I can adjust while sailing.  I have only a 90 w panel but it puts out about 8 amps peak in strong sun.  Any shadow ( eg. mast) kills the output but my mounting is outboard of most shadowing effects such as shrouds.  I could use a stronger panel but it tops me up pretty well unless we are at anchor for several cloudy days.  Coupled with a 120 amp alternator, I find that there are few days while cruising that we do not motor for an hour or so anyway.  I bought the system in 2013 so I am sure efficiency has improved since.   Bruce
Bruce,  OKAGA, A32

Jackrabbit

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Re: Solar panel arrangements
« Reply #9 on: October 21, 2019, 04:11:22 PM »
Those pole mounted kits look pretty slick.  How do they hold up in strong winds, etc?  I'm thinking that if the boat were left on her mooring unattended during the week the panel might be up and exposed to gusts.

Holdech

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Re: Solar panel arrangements
« Reply #10 on: October 22, 2019, 09:12:07 AM »
I thought of a few tips to pass on that may be of use.

If you really want to rigidly back a flex panel and provide ventilation, use the Lexan sheets designed for greenhouses. They are essentially a corrugated design so air can circulate.
Note that I'm not talking about the corrugated plastic (corplast etc) sold at the lumber stores. The Lexan is close to 1/2 inch thick and does not bend. The killer of semi-flex panels (this from a supplier) is continuous small flexation. The panels are not designed for that.

The Lexan backing is also excellent for lifeline mounted panels that you pivot up at anchor and stow down when sailing. Much lighter than rigid in this case. A few YouTubers use this arrangement.

Regarding pole mounting, the current generation of rigid panels has a very wide sun angle. Also, being flat and not curved with the bimini top effectively increases sun angle by close to 30 %.
I have experimented with tilting my panels and the difference was not nearly as much as I expected. Pole mounted doesn't work very well for anchoring or on a mooring unless you are there to constantly adjust it. My panels put out close to 50% output at 8 am (mid-summer) and the nightly energy used is replaced by noon on most days. If the boat is unoccupied then it's replaced much sooner. In my case, I prefer simple and automatic. But I do have a friend (liveaboard) who has four 100 watt rigid panels individually pole mounted. He insists the exercise he gets adjusting them throughout the day provides much-needed fitness. He has never had an issue in strong winds with his setup. I'll try to find a picture if I can.

Chris, Teliki, A32

Bruce

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Re: Solar panel arrangements
« Reply #11 on: October 22, 2019, 11:41:47 AM »
My pole mount has never been an issue in wind.  In fact, I leave it mounted over the winter with no ill effect!  As a type A, I quite like periodically adjusting the angle toward the sun but when I am not aboard, my boat is plugged into the marina grid and is shut off at that time.  I mounted a kill switch in the circuit for this purpose.   Bruce
Bruce,  OKAGA, A32