Vertical solar panel

[Graham_Wright]

I recently visited son at his girlfriends house. The garden is modest and the roofs not ideally angled for panels.
He has used the vertical panel garden fence for attaching the panels and it is very successful. If you do the trig, there is not a huge disadvantage and the panels he has installed run the wholc house ( in "summer").
That arrangement started me thinking about boat arrangements. I currently have two panels one each on the pushpit rails. There is no ideal additional space. However, I could hang a couple on the guard rails. They would be near vertical and thus far from ideally angled. BUT, as those who have been burned by reflected reflected from the water will know, there is a sizeable insolation available.
Perhaps worth an experiment.

 

[geem]

I recently visited son at his girlfriends house. The garden is modest and the roofs not ideally angled for panels.
He has used the vertical panel garden fence for attaching the panels and it is very successful. If you do the trig, there is not a huge disadvantage and the panels he has installed run the wholc house ( in "summer").
That arrangement started me thinking about boat arrangements. I currently have two panels one each on the pushpit rails. There is no ideal additional space. However, I could hang a couple on the guard rails. They would be near vertical and thus far from ideally angled. BUT, as those who have been burned by reflected reflected from the water will know, there is a sizeable insolation available.
Perhaps worth an experiment.

If you mount panels on the guardrails, you can have any angle you want. We have 2x180w of solar panels on each guardrail (720w in total). They function as spray dodgers at night in the down position. When deployed on anything from horizontal to angled they can collect the maximum amount of power when sailing or at anchor. We have done lots of miles with this set up and wouldn't change it

 

[TSailors]

If you mount panels on the guardrails, you can have any angle you want. We have 2x180w of solar panels on each guardrail (720w in total). They function as spray dodgers at night in the down position. When deployed on anything from horizontal to angled they can collect the maximum amount of power when sailing or at anchor. We have done lots of miles with this set up and wouldn't change it

How do you attach those panels to the guardrails?

 

[Graham_Wright]

If you mount panels on the guardrails, you can have any angle you want. We have 2x180w of solar panels on each guardrail (720w in total). They function as spray dodgers at night in the down position. When deployed on anything from horizontal to angled they can collect the maximum amount of power when sailing or at anchor. We have done lots of miles with this set up and wouldn't change it

They are only adjustable if you are on board. My question was aimed at the theoreticians to help with the trig.

 

[Sea Change]

Like geem, we have guardrail mounted panels. We angle them to catch the sun and then just leave them up, like wings. We only drop them to vertical when going alongside. Crossed the Atlantic with them 'deployed' without a second's worry.

I've seen all sorts of ways of arranging them, most people over think it IMHO.

Drill some holes in the aluminium frame, fit some bulldog clamps around your guard wire. Don't clamp them down too tight.
Use a stick to prop them up, with a light, tight line down to the toerail. Or if you're as lucky as me, just hang them from a convenient nearby point- we have a defunct wind gen pole on one side and an aerial mast on the other.

 

[geem]

They are only adjustable if you are on board. My question was aimed at the theoreticians to help with the trig.

We have just been in a marina for a couple of weeks whilst we hosted visitors. The panels were vertical but susceptible to shading from adjacent boats. We still had plenty of power for fridges and cooking on lithium. We halved our solar output but without shading I suspect they would have done pretty well

 

[oldmanofthehills]

At the equator 0 degrees the sun is at 90 degrees to horizontal at midday on the equinox. Panel ideal on that day =0 degrees to horizontal

Very rough calcs: -

In the UK at about 50 degrees north the sun at mid day is never above 40 degrees or so to the horizon at equinox. So panel for that needs to be at 50 degrees to horizontal. And at midday on Midsummer June 21st it changes by 23 degrees to about 27 degrees from horizontal, in mid winter it needs to be 73 degrees to horizontal.

So most roof panels at about 45 degrees are optimised to give maximum output at midday on the equinox as it is a/easy to install and b/ seems more effective than they actually are all day year in year out - all of which may be less useful for a boat which may want power in winter, dawn or early evening etc

 

[thinwater]

The advantage of horizontal is that they are effective on ANY heading. A house doesn't move, so you can aim them south. For example, the efficiency will be low to near zero for 2/3 of the headings.

But a good thread that has me thinking about a new fence we put up.

 

[Trident]

We've hung light weight flexible panels off the cockpit cover with magnets vertically to get the best angle on the sun early in the morning and late in the day - of course we're on board to put them flat between those times too. Mostly this was to test the improvement with the angle but certainly for some of the day you would get a good output .

 

[B27]

Reflecting the sun can be a big problem with vertical panels.
Dazzling people etc, or just being annoying..
But near-vertical panels angled East and West can be very useful, as you can get longer hours of battery charging or whatever.
Longer hours may be better than higher peak power, as you may not be able to use, store or export the peak time power.

 

[lustyd]

A house doesn't move, so you can aim them south

The latest research shows that having vertical bifacials with the faces east west yields more power as you get good solar twice a day rather than once in the middle. Lots of videos explaining on YouTube if you search vertical solar panels.
Obviously as you said, a boat is hard to pin north/south for vertical side panels, but I thought worth a mention that south isn’t considered best any more after proper research (or north for our southern cousins)

 

[thinwater]

The latest research shows that having vertical bifacials with the faces east west yields more power as you get good solar twice a day rather than once in the middle. Lots of videos explaining on YouTube if you search vertical solar panels.
Obviously as you said, a boat is hard to pin north/south for vertical side panels, but I thought worth a mention that south isn’t considered best any more after proper research (or north for our southern cousins)

Good point and the math works. But ...

a. That is only for bifacial panels. You can make a good case that bifacial panels are the way to go, but ...

b. The math only works if they are clear on both sides, which is not common on most boats. Not common on most fences. Large solar installations are not really relevant to most homes or boats. I've heard people make the argument that used for a bimini you get light from underneath, but based on the testing I did for some sunscreen projects, there is only about 15% as much light available on the deck under the shade and 5-8% on the underside of the hard top. It's called shade. It could be more if the entire cockpit were bright white gelcoat, without any cousions etc, but who would want that? Also, many sailors deploy side curtains at anchor.

c. The aspect of the boat (N/S) will change through the day which is why flat works (flat is omnidirectional). Most boats yaw a good bit at anchor and the wind and tide change. I'm not going to be a slave to aiming panels.

So yes, south is still best for conventional panels, and flat is best if you cannot control the aspect. The basic rules of shade and geometry have not changed.

I'm glad to have a cat with enough hardtop and deck. No such fiddling is required. If it was, I'm pretty sure I would reduce power use instead. But yeah, that is a big difference. Normally the hard top alone is enough, but add the sallon roof if you are power hungry.

 

[Sea Change]

The only yacht I've seen with bifacial panels was a cat with them hung off the back, where they could pick up reflected light from the sea. The owner was very happy with them.

 

[William_H]

Interesting discussion. For any individual boat or home owner requirements will be different. Do you need power in winter? If so then large wattage panels angled low would be ideal. But as we see on boats it is not the cost of panels that matters so much as the mounting arrangements cost and convenience.
Just to upset my friends I went to a house demolition type second hand house stuff yard. He had s/h, claimed 260 w 40 v panels for 25 oz dollars or 13 pounds to you. He had a few of them. This reflecting the huge number of houses with solar PV and houses being knocked down. Great but at 2m x 1 m not so convenient on a boat. Unless it is a cat or big mobo.
Anyway an amp meter will soon indicate if vertical mounting of PV panel is useful or an acceptable compromise. But nothing matches an auto ajusting sun following mount. ol'will

 

[geem]

Good point and the math works. But ...

a. That is only for bifacial panels. You can make a good case that bifacial panels are the way to go, but ...

b. The math only works if they are clear on both sides, which is not common on most boats. Not common on most fences. Large solar installations are not really relevant to most homes or boats. I've heard people make the argument that used for a bimini you get light from underneath, but based on the testing I did for some sunscreen projects, there is only about 15% as much light available on the deck under the shade and 5-8% on the underside of the hard top. It's called shade. It could be more if the entire cockpit were bright white gelcoat, without any cousions etc, but who would want that? Also, many sailors deploy side curtains at anchor.

c. The aspect of the boat (N/S) will change through the day which is why flat works (flat is omnidirectional). Most boats yaw a good bit at anchor and the wind and tide change. I'm not going to be a slave to aiming panels.

So yes, south is still best for conventional panels, and flat is best if you cannot control the aspect. The basic rules of shade and geometry have not changed.

I'm glad to have a cat with enough hardtop and deck. No such fiddling is required. If it was, I'm pretty sure I would reduce power use instead. But yeah, that is a big difference. Normally the hard top alone is enough, but add the sallon roof if you are power hungry.

Bifacial panels work well in low ambient temperature but their performance suffers as the panel surface gets warm. The tests read in scholarly articles suggested at best 4-6% increased output.

 

[Neeves]

but I thought worth a mention that south isn’t considered best any more after proper research (or north for our southern cousins)

Thank you for the thought.

Jonathan

 

[lustyd]

Bifacial panels work well in low ambient temperature but their performance suffers as the panel surface gets warm. The tests read in scholarly articles suggested at best 4-6% increased output.

Given that the overall power input is higher, does that really matter? Efficiency doesn't run my fridge, power does.

 

[onesea]

How do you attach those panels to the guardrails?

You buy ridged panels as they are cheaper mount them on the middle guard rail using extra long plastic cable glands. That way you can still easily rotate them.
If anyone is interested I can make post of how it’s done. For very little money.

I have 2x100w of solar as side screens. 90% of the time they stay down on wet grey days I can put horizontal to get enough watts in reality it’s rare I have had to do this in 2 months of this summer.
It’s normally when sailing into the sun or on anchor that I do it. On grey days where solar power is minimal.
It increases back ground 30watt to 50 watt, meaning I have no shortage of power.

I have considered installing flexible panels back to back but the reports on here how poor flexible panels are say it’s not worth it.

Much of the time they are better vertical to get early and evening rays.

The answer is yes it works, yes you can get more by rotating panels, I can rotate mine 180 degrees in practice this only gets me about 1/3 more. Which if it’s fine don’t need, only on wet rainy days where solar is at a premium.

 

[geem]

Given that the overall power input is higher, does that really matter? Efficiency doesn't run my fridge, power does.

I never said it did matter I was pointing out the increase in efficiency you can expect if you go that route. If you watch all the none scientific tests on utube you may think you will see huge increases in output. You don't. It's a small increase and less so if you sail in the tropics as they get hotter than conventional panels that have a white backing

 

[Graham_Wright]

But nothing matches an auto ajusting sun following mount. ol'will

We have one of those on our camper. The Zzzz,Zzzz,Zzxzz as it tracked the optimum angle drove us mad! The claimed hysteresis adjustment we could never find.