Which Solar Panels for this giant hardtop?

[rslifkin]

Originally Posted by Lost Horizons

Is there a particular reason, other than a desire to sell a “project,” why large solar panels are not sold to end consumers? The highest capacity panels available on Amazon are 200 W, and there are not many choices there in this size, the vast majority is 100 W. I suppose, shipping can be a problem, but then local marine stores like Fisheries do not carry them either. I would like to get a couple or maybe initially just one 400 W panel, but it looks like it is not going to happen. Will probably go with three 200 W panels from Amazon, which I hate to do, but there seems to be no alternative. Am I missing something?

It's definitely possible to buy large panels, but it seems like there a limited number of places that sell them. And some places or panels have a minimum quantity, requiring you to buy 6 of them in some cases. The selection is limited as well, as some manufacturers don't seem to like their panels being listed online with prices and a "buy" button. Feel free to PM me and I'll share the places I've found so far.

[Scott Berg]

We just did a cat with 12 Solara 150w walk on panels and 6 Victron controllers (we put two panels each in series); amazing, flush mounted, walk on, etc. SunPower cells. Hard to imagine a better installation. Not cheap. On my boat's hard top I have 2x Kyro 315 and 2x SunPower 327 for 1.3kw with 4 dedicated controllers but we're a sailboat and shade is the enemy. We'd love the walk on panels but left a narrow walking path and we had these left over from jobs and couldn't beat the price! Whatever you do you'll love!

[Lost Horizons]

Originally Posted by rslifkin

It's definitely possible to buy large panels, but it seems like there a limited number of places that sell them. And some places or panels have a minimum quantity, requiring you to buy 6 of them in some cases. The selection is limited as well, as some manufacturers don't seem to like their panels being listed online with prices and a "buy" button. Feel free to PM me and I'll share the places I've found so far.

Thanks, I saw some specialized vendors with the larger panels. Still wonder why places like Amazon, Defender, Fisheries, Home Depot, etc. do not carry them. The answer may be as simple as the shear bulk of those panels or a code requiring certain proficiency from installers.

On a second thought, I may be better off installing two or three 200 W panels above the bimini, which already has rails for this purpose. Its 1.25” frame will probably support the weight of three 200 W panels. Placing two 400 W panels there may be tricky due to their dimensions. I may attach an additional 400 W panel to the dinghy arch later if I still need more electricity.

[rslifkin]

Originally Posted by Lost Horizons

Thanks, I saw some specialized vendors with the larger panels. Still wonder why places like Amazon, Defender, Fisheries, Home Depot, etc. do not carry them. The answer may be as simple as the shear bulk of those panels or a code requiring certain proficiency from installers.

On a second thought, I may be better off installing two or three 200 W panels above the bimini, which already has rails for this purpose. Its 1.25” frame will probably support the weight of three 200 W panels. Placing two 400 W panels there may be tricky due to their dimensions. I may attach an additional 400 W panel to the dinghy arch later if I still need more electricity.

For whatever reason, the smaller, lower voltage panels seem to get targeted at the off grid market and there's an assumption that the big, high voltage panels won't be used for that.

[Scott Berg]

There is also the shade issue; we prefer to install more smaller panels located so as to not "share the shade" with other panels

[SunPoweredYachts]

Originally Posted by Peeew

Try https://www.sunpoweredyachts.com/ for advice. They helped me a lot with my planning.

Thank you. appreciate you recommending us. We're here to help answer any questions on going solar aboard and highlight the SunPower advantages. With a good amount of 'roof space' aboard that can support the size and weight of the SunPower fixed frame panels I would recommend either the SunPower 370W or 410W.

Often with boats it's a case of checking the panel dimensions and choosing which panel will physically fit best. We can then also help with the other system components to get you up and running eg. MPPT charge controllers, circuit breakers, PV extension wire etc

I always like to also mention the Federal Tax Credits that you might be able to take advantage of, it's been extended for another 2 years at 26% on the total system cost.

Aloha, Lyall

[Senojev]

I just looked up a couple of Home Depots located in AZ and they have a good selection of panels (free delivery) from Renogy and Grape Solar. I have had two of the 300W Grape Solar and have been please with their performance. In their 5th season with no issues.

[Jon Hacking]

Coder, As you point out, most quality panels have the same marine ratings, so probably not worth worrying about. They all seem to be glass with plastic backs, tightly sandwiched into an aluminum frame with a flexible gasket. Our Kyocera panels were still going strong after 11 years, mounted above the davits, about 10' off the water, so similar to yours, but ours were exposed on the bottom.

Physically, we didn't mount them to much of a frame, as their own frames are quite strong. We screwed the leading edge to our targa bar, which is pretty solid but shudders when we tack or gybe, as the mainsail track is on top of the targa bar. Our davits consisted of 2 horizontal bars extending aft from the targa bar, & to them we added an aluminum cross-bar as far out as we could, about 4' aft, but the panels extend out another 2', supported only by their aluminum frames. So minimal support, but no problems, & we used that setup to cross the Caribbean & Pacific, & the Indian Ocean twice. I think any support you have will be more than ours, so probably not worth worrying about either.

Perhaps more important is your other clutter up there. Note the long shadows in your photo. ANY shading will pretty much turn off whatever panels are hit. You don't lose just the output from that one cell, you lose much more. You *really* want to minimize shading on your panels. Also, the more MPPTs the better, as shade will affect the entire series string of panels, not just the panel being shaded. There are lots of discussions on how best to wire panels when shading's an issue.

Back in 2009, Kyocera replaced our (then) 4 panels for free, air-freighting them to us in Malaysia because they'd had a bad batch come out in 2001, when we first bought ours. Although this is rare, it's good to know.

In early 2020, we replaced our Kyocera panels with more efficient 400W Powitt panels. Yes, they're Chinese, & we've only had them a year, but Powitt produces a LOT of panels. More importantly, they guarantee them, with a 12-year materials & workmanship & 30-year(!!) performance guarantee (which is much like our Kyocera panels). And at only $0.50/W, so $200 for a 400W panel, they're a steal (& they're even cheaper now). OK, I mounted them myself, after buying some mounting hardware from my dealer, who usually supplies panels to land-based contractors here in the Philippines.

I think you know that bigger (more powerful) panels are more cost efficient. Our 3x400W panels are 72-cell, & each feeds its own MPPT. They're pretty close to 1x2m, so a bit bigger than our 4x120W Kyoceras, but they produce MUCH more power for us.

You seem more interested in getting them to fit than actual power, which is certainly your prerogative. But you should know that letting your panels overhang your space a bit, even by a foot or 2, is not really a problem.

Good luck!

[UFO]

I installed one of the following last year and am very happy with it - Similar size to the LG, but built incredibly well which will help withstand the trials of being on a boat. The panel is also split into to sections so if one gets shaded the other still cranks.


https://www.recgroup.com/en/alpha

[codingparadox]

Jon: I'm planning on changing literally everything on the roof. Pulling off the satellite dishes, the FLIR, etc. New tower from Seaview is on the way that angles way back. I'll be optimizing for lack of shading, and doing everything in parallel just in case I do get shading, to minimize the effects. So assume I'm doing the wiring right. I'm trying to get the most wattage on my roof while still being able to maintain things (i.e. walk around carefully.)

Basically all of the 60-cell panels seem to be pretty similar. 61-66" long, 40" wide. The 72-cell ones are 80" long which would be quite a lot of overhang on the boat, also picking up quite a bit of windage at the edges.

I checked out the REC. The double-area parallel thing is neat, but the rest of the specs of the panel look pretty identical to the LG. But an interesting option.

[LargeMarge]

2003, we converted a 1997 Ford CF8000 commercial truck to our concept of an ExpeditionVehicle.

We have six 305-Watt photovoltaic panels -- 1,830-Watts -- feeding our AGMs.

After nearly two decades of full-time live-aboard, I think your 'bonkers' idea is realistic.
But, then, we revel in weird, so there is that.