Large solar array support beams

[CaptainRivet]

Originally Posted by s/v Jedi

Okay, laptop does attachments so here they are

Nick that broken part looks like a 90 degrees alu part to connect two pipes with grub screws. So that was the lower part/frame of alu tubes where the solar panels were directly connect to, correct?

[CaptainRivet]

Originally Posted by sailingharry

Ouch! Big flat surfaces with big winds make really big loads!


My new arch is being built with stainless mounting tabs directly welded into the arch, built for the specific panels (great for this round, let's not think about a future upgrade....). But, those loads are why I really struggled with my choice of panels -- 50% of my panels will be aft of the main arch structure, and 30% will be aft of the solar support extensions. I have serious concerns about the ability of a panel to self-support nearly 2' of surface aft of the last support. But in the 15 years I've owned a cruising sailboat, I've never seen winds over maybe 60 kts -- so the risk is fairly low...hopefully...LOL

That overhang depends on the panel itself, especially the alu-frame around it. If its a cheap L shape i would have concerns.
Best in this case are bifacial panels as both sides are supported by the glass and additionally all quality bifacial panels have rectangle tubes of 3 till 5mm of alu with a lip. The also produce backside 20% which is on arches reachable. My longli 365W bifacials have a sturdy 35mmx15mm thick frame incl a lip in 3mm alu. I connected them directly by drilling additional holes into the frame with M6 big head bolts, isolation washers and nuts to the stainless steel structure underneath and also connected the panels directly to each other all 30cm with m5 big head bolts isolation washers and nuts to each other, so they support each other too. Thats also acts as roof for the dingy on davits underneath so rain doesn't fill it up.

Downside of bifacials is they weight more but that gives them also the stability. As always compromise on a boat....

[Pete7]

Originally Posted by s/v Jedi

PAlso, a test of the lashings to be used for mounting to the arch. It is actually a whoopie sling from 2.5mm Amsteel Blue that is tightened with a lashing from 2.2mm Lash-It.

Looks like someone has been reading the late James Wharram books

[s/v Jedi]

Originally Posted by sailingharry

Ouch! Big flat surfaces with big winds make really big loads!

My new arch is being built with stainless mounting tabs directly welded into the arch, built for the specific panels (great for this round, let's not think about a future upgrade....). But, those loads are why I really struggled with my choice of panels -- 50% of my panels will be aft of the main arch structure, and 30% will be aft of the solar support extensions. I have serious concerns about the ability of a panel to self-support nearly 2' of surface aft of the last support. But in the 15 years I've owned a cruising sailboat, I've never seen winds over maybe 60 kts -- so the risk is fairly low...hopefully...LOL

That last array I had was setup like what you describe. I had 40% of the panels overhanging the aft most support… or at least visible support. All along the long side of the panels I added aluminum angle profile -inside- the solar panel frames and riveted them on both sides of the angle. This extended the frame invisibly all the way aft. This was very strong and didn’t even fail when hurricane Ian started smashing it around.
Also, I added small pieces of VHB tape in between the panels at the back and that held too.

We had had up to 80kts gusts with that array while at anchor without problems. Now with Ian we only had 45-50kts but we were on the hard so much higher up and the wind came from the back quarter, somehow the ground and stern allowed the wind to come up under the array.

Now I get these carbon fiber beams all the way aft of the panels and with the sliding panels in stored position, it’s only 2/3 of the surface area.

The lashings will be much stronger than metal/stainless tabs welded. Not just because the tensile strength is higher but also because they wrap all around the arch tubes.

[s/v Jedi]

Originally Posted by Pete7

Looks like someone has been reading the late James Wharram books

I have read every word written by James Wharram, Brion Toss and Evans Starzinger

I saw Wharram do the lashings with an eye at one end but it was Starzinger describing the perfect lashing which is tightened by another lashing

[sailingharry]

Originally Posted by CaptainRivet

That overhang depends on the panel itself, especially the alu-frame around it. If its a cheap L shape i would have concerns.
Best in this case are bifacial panels as both sides are supported by the glass and additionally all quality bifacial panels have rectangle tubes of 3 till 5mm of alu with a lip.

These are no-name panels, which has me a bit nervous, but they are the ONLY panels I found that met my objectives (fit in the space, 400W or more, and don't extend too far back for aesthetics (and support).
They are still in the box (I pulled them out to take some detailed measurements for the arch builder -- shout out to Klacko in Ontario, incredible work -- and put them away for safekeeping until installation).

They are bifacial, but I think the back side is NOT glass, but clear plastic. That was mentioned in a review, with the additional comment that solar degradation on plastic on the back side is likely to be very minimal.
Dimensions indicate that it is a box-beam. The lower flange is 1.25" wide, but the inside lip is only .75" wide, meaning the box is about 1/2" (12mm) wide.
https://www.amazon.com/dp/B0C5R7R4C9 -- I did some metrics comparison to try and validate the product, and $/W, W/M^2, lb/W all seemed in line (all REAL panels will mostly line up on those metrics, as no one has any "secret sauce" and wild variations are all.... optimistic).

[sailingharry]

Jedi, Earlier in the thread, you indicated that your stern was only 3M wide. That makes your stern even thinner than mine -- my 43' boat is not much narrower! I see you hang a dinghy back there -- which means like me, you are constrained on dinghy size. How big is your dink? I've got a 2.8M, and wish I could fit a bit more.

[s/v Jedi]

Originally Posted by sailingharry

Jedi, Earlier in the thread, you indicated that your stern was only 3M wide. That makes your stern even thinner than mine -- my 43' boat is not much narrower! I see you hang a dinghy back there -- which means like me, you are constrained on dinghy size. How big is your dink? I've got a 2.8M, and wish I could fit a bit more.

We have a Highfield Classic 320. The cassette is 240cm wide in retracted state. The panels I have are 44” wide with the two fixed panels on top almost touching each other in the middle, but the sliding lower panels further apart so that when they slide out 44” they have some separation from the upper panels to prevent shade from those. Also, this gives some space between them underneath for securing them. I mounted small cleats on them.

The Renogy 450W bifacial are a good amount shorter than the 550W but my beams are longer and I could build a new cassette back rail to fit the 550W panels instead…. if I ever feel crazy enough

[s/v Jedi]

Funny, uploading pictures from the iPad works again.

So the beams are finished with two coats of polyurethane. The cassette rails have two coats on the inside but only one on the outside so here I’m about to sand them for their second coat, while the beams will be curing for another day to get the paint harder.

[CaptainRivet]

Originally Posted by s/v Jedi

We have a Highfield Classic 320. The cassette is 240cm wide in retracted state. The panels I have are 44” wide with the two fixed panels on top almost touching each other in the middle, but the sliding lower panels further apart so that when they slide out 44” they have some separation from the upper panels to prevent shade from those. Also, this gives some space between them underneath for securing them. I mounted small cleats on them.

The Renogy 450W bifacial are a good amount shorter than the 550W but my beams are longer and I could build a new cassette back rail to fit the 550W panels instead…. if I ever feel crazy enough

Top notch work....i would have just taken the 550W right away from the beginning. You can never have enough solar

[s/v Jedi]

Originally Posted by CaptainRivet

Top notch work....i would have just taken the 550W right away from the beginning. You can never have enough solar

The other array is currently 2x 375W LG NeonR panels where there is no possibility of mounting anything larger than the 450W Renogy panels.

So when the time comes to replace those two LG’s with four panels in cassettes like on the arch, I may move the 450’s there and get 550’s.

But for now we have enough power. The old array on the stern was 3x375W LG’s and together with the other two for a total of 1,875W we had enough power for everything incl. A/C. Now we get about 2,750W so a substantial upgrade and we should be able to live in luxury so we’ll first see what comesof that

[s/v Jedi]

All painting finished incl. a test cockpit table top in white Awlgrip. We will test a Lagun 3D adjustable table leg with that.

Now we start coating the backs of the slides with cosmoline.

[CaptainRivet]

Originally Posted by s/v Jedi

The other array is currently 2x 375W LG NeonR panels where there is no possibility of mounting anything larger than the 450W Renogy panels.

So when the time comes to replace those two LG’s with four panels in cassettes like on the arch, I may move the 450’s there and get 550’s.

But for now we have enough power. The old array on the stern was 3x375W LG’s and together with the other two for a total of 1,875W we had enough power for everything incl. A/C. Now we get about 2,750W so a substantial upgrade and we should be able to live in luxury so we’ll first see what comesof that

Ok thats serious solar power on a mono :-)
Did you test the renogy panels? Will Prowse was not so happy with them...not the exact same model you have. Undertaking the huge effort you do top 5 makers or LGs top model whould have been just good enough for me to use...why renogy known for being acceptable budget with average reliability. Using their 60A DC2DC (and only this model as you can reduce it to 30A and supercheap compared to Victron) but only this and bought over amazon knowing about their shitty customer service...i posted about renogy being good and cheap for what they deliver as having good experience with this 60A DC2DC here and got a shitstorm back how bad they are in general and quality.

Also to sailingharry i believe the ratings of Longli, sunpower, LG and other top 10 makers as they are always within whats speced mostly overdelivering like LGs.
If a smaller panel gives you a bigger rating its 99,9% purposly overspeced. So when eg you sailingharry said its the only above 400W in that measurement, then its 99,9% overspeced and won't deliver the 400W.
@sailingharry: If i would be you i would unpack and test them for some time exactly the way you install them bevor you do the huge effort addapting the ss arch, re-enforcing and then later wake up (hope not) that they deliver much less. Also the difference between cheap and top 10 is lowlight and the angle when they start producing. Means under perfect conditions (which are seldom there) they deliver equal to top 10 but in not ideal they deliver almost nothing while eg an LG or Longli deliver 60% of its rating and start much earlier. Additionally top one have more diodes and busbars means are much less affected if a part of the solar panel gets shaded.
Also all the top 10 with bifacials only the frontside is rated eg my Longli are HIMo4 365 means 365W rated but in real life they deliver up to 450W as the add on come from 20% backside which eg Longli state in a different table on the spec sheet. Cheap noname often state and spec the combined power.

[CaptainRivet]

@sailingharry: Just read/checked your panels.

https://www.amazon.com/dp/B0C5R7R4C9 --

My longli HIMo4 365 are 173cm by 103cm, your 10BB 182x182cm so even 10cm less length and 70cm smaller but Longli HIMo4 365 speced 365W delivering regularly 450W on very good days, average on anchor between 10 and 5o'clock is over last 5 month is 330W of 365W rated =90% of its rating due to my victron MPPT and CerboGX.
Reading the reviews these noname panels even do their rating under perfect condition and eg stating 2400W installed delivers peaks of 2500W (means their rating is front&back combined) but average 1800W=75% of their rating means your 182cmx182cm panel 400W will deliver 300W...10% less then my significantly smaller Longli for 183Euro per panel.
Means 3xlongli would be 173cmx 309cm deliver 1350W peak and 990W average while 2 of yours are 182cmx364cm deliver 850W peak and 600W average means 3 Longli deliver 1/3 more on a smaller surface.
Thats worldmarket leader Longli via noName...
If i would be you, sell them and look for quality that are as close as possible to that measurements. The longli are 144 half cut cells panels and are standard size for this class 72cells or 144 half cells class. Advantages if they break you most likely find similar size to replace without changing the arch. I had the same LG 375W then Jedi before, very good panels too and quite equal on anchor but big difference due to shading when on passage...my longli do 700-750W on passage while LG where in 400-450W range due to more prone to shading then bifacials. Just replaced because another sailor couldn't berth his boat properly and killed 2 of the 3 panels, no changes to arch. Wanted to have the LGs but they were not available and Longlis were a lucky punch and a bragain with pavkage offer 600Euro for 4, sold one for 200Euro so my 3 panels actually cost me 400Euro...thats what nearly one LG cost here 338Euro.

[Pete7]

Originally Posted by sailingharry

They are still in the box (I pulled them out to take some detailed measurements for the arch builder -- shout out to Klacko in Ontario, incredible work -- and put them away for safekeeping until installation).

Seems quite normal for the large panels and caught me out when we moved from 150w to 300w as I didn't realise the frame edge is a box so less area to apply bolts on the inside. I ended up having to file dozens of stainless steel penny sized washers taking the edge off them.

Suddenly there is a dearth of bi-facial panels in the UK unless you go to 550w or so. I get the market isn't big because they would be a fat lot of use on a roof, but still all gone?

Pete