I have a 40 watt panel fitted vertically each side of the pushpit on home made SS brackets. Top edge is about the same as the top rail. I sail with a windvane and the panels don't interfere.

looks like I will go down the batwing mounting style like the attached photo. Does anyone know where to get the black tubing brackets shown in photo.

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This is about the best I can do John. The panels are fixed in position with SS tubes with black plastic rail fittings on the ends. Panels are not quite vertical and are set parallel with the centreline.

If you have a pole mounted one corner of your transom with a vertical axis swivel that allows as close to but not more than 359 degrees of swing, atop of which you have another swivel with a horizontal axis that allows as close to but not more than 179 degrees of swing, you will have an ideal place to mount a solar panel or two.

The swivels need to be able to be clamped at any degree of their angular range.

Sorry I can't post a picture of the set up as I have only ever seen it on one yacht about 15 years ago. It was a Kelt 39 (now called Feeling 39s).

The pole needs to be of sufficient height so that you don't gouge your scalp on the corners of the solar panels.

This set up allows adjustment of the panel/s to receive the sun's rays at 90 degrees almost anytime of day regardless of heel angle of the yacht.

Another benefit is that it allows the panel to "feathered" when the weather gets up.

Now that we have this set up on one side of the transom the yacht looks and is a tad unbalanced.

We could do the same on the other side, but why would you?? Far better if on the other side we have a pole with a wind generator sitting atop it set at sufficient height so that the blades don't chop you ears off. Just as it was on the Kelt 39.

So here we have a system that gives electricity under just about any scenario, be it at the marina, at anchor or under sail.

When the wind's a blowin' and the whips a'crackin it is usually overcast, so feather the panel and free the prop.

When the sun's a shinin' and there's barely a breeze, feather the prop and free the panel.

The whole set up looks a lot neater than these huge gantries that are so common on the back of yachts these days. For cockpit shade under sail a foldable bimini is the way to go.

HaveFun said...
Pardon my ignorance here but I understand the irradiance from the sun (and hence) solar power output to be maximum at solar noon when the sun is directly overhead. So with the panels mounted close to vertical as in the picture how much power is produced? I am not being critical I just want to know if the system works and, presuming it does, how much power?

They produce pretty much the same power as if they were at 90 degrees to the sun. Experiment with a test meter and see. I followed the example of one of the other local boats who set his up so that they tilted up to the horizontal position when at anchor. He found there was no practical advantage to this and now leave them at the vertical position.
What most people don't realise is that solar panels are heat sensitive and once they get to a certain temperature [can't recall what it is of the top of my head but think its about 27c] they produce less power. Placing a black surface at 90 degrees to the midday sun in summer will actually produce less power!
My yacht is actually used for sailing and nothing is added that will slow it down, certainly not air brakes or any added weight in the ends if it can be avoided. When the yachts heeled obviously the panels are pointing higher or lower but watching the regulator they always show a charge. The yacht is on a swing mooring in a tidal estuary and battery power is never a problem.

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Out sailing today so took a photo of one panel. Later in the day, about 1330 I was sailing with the sun right over the stern at about 80 degrees, sun was only directly on the alloy frames. Both panels showed 13.4v, one battery was 13.4 and the other one that was in use 13.2v, laptop and stereo running.

MorningBird said...
My understanding of electrics isn't good, see my other post, but my understanding is it isn't the voltage from the panel that counts, it is the current.

Your understanding is spot on regarding the output from the panels, it is indeed the wattage. Voltage is the measure of electrical pressure and wattage is the amount of juice that is flowing.

Ramona said...
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Out sailing today so took a photo of one panel. Later in the day, about 1330 I was sailing with the sun right over the stern at about 80 degrees, sun was only directly on the alloy frames. Both panels showed 13.4v, one battery was 13.4 and the other one that was in use 13.2v, laptop and stereo running.

Seems to defy logic but I guess the figures don't lie.

How much bark have those two long bolts taken off so far?

I thought a "Tiffy" might notice the excess threads! They are on both panels and are used to prop the tips of my fishing rods, when I get around to it I will have to make a couple of plastic fittings to go over the threads. Apart from when I install the windvane blade before I leave the mooring I don't go near the panels.

The figures I quoted for the panels yesterday was with the sun shining on the alloy frames, the sun was more than 90 degrees from the front surface. With the sun shining directly on them they will read up to 17 volts. The measurements I gave were taken off the front terminals of the regulator. So with the panels charging each separate battery, the one panel in the shade was able to maintain a battery at 13.2 volts with a laptop with a max draw of 4 amps running. Doubt whether a laptop just running a nav programme would use anywhere near 4 amps and the stereo and radio would have little drain.

Ramona please tell us voltage on the battery with some load on.

If voltage is from 12.6 V to 14.2 the battery is under charge.
If voltage is 11.6 battery has 50% capacity left.
If voltage is under 10.8 V stop using the bat. And start charging.

Safe available range would be from 12.6V down to 11V.

I'm with QLDCruiser on solar panel operation. Mine is tied down on the port side of the cabin top, to maximise charge on the mooring. I can easily move it to the stbd side when required, say when returning from Lord Howe.
The previous owner installed a regulator for the panel but I am not sure what type it is. The batteries don't cook and are always charged so I am assuming it is OK.
I am going to make a mount like Ramonas but with a hinged stay so I can swing it to the horizontal when moored/anchored and in benign conditions at sea. A mate with an S&S34 has an 80w panel fixed in position on each side of the cockpit. He lost one to a wave. Made a mess.

Charriot said...
Ramona please tell us voltage on the battery with some load on.

If voltage is from 12.6 V to 14.2 the battery is under charge.
If voltage is 11.6 battery has 50% capacity left.
If voltage is under 10.8 V stop using the bat. And start charging.

Safe available range would be from 12.6V down to 11V.

From my previous:
"the one panel in the shade was able to maintain a battery at 13.2 volts with a laptop with a max draw of 4 amps running. Doubt whether a laptop just running a nav programme would use anywhere near 4 amps and the stereo and radio would have little drain."

The laptop, HF and VHF plus the stereo is really the only load I have. No real point in having a battery under load higher than 13.2 volts. My yacht is for sailing. There is no way I would cart a pile of SS construction on the rear end with an enormous panel about that would have an excess of charging capacity.
With the previous owner this yacht did 5 Hobart races, 3 Lord Howe races with battery power only. Some of these races were up to 5 days long. I'm sure they only used the HF in Bass Strait and the laptop was only used for short periods. With no fridge and new technologies very little battery power is required.

Charriot said...

e best way how to understand your panel is before the installation
Connect the globe / say 40 W panel 15-25 watts globe/ directly
to the panel and move panel around, different angels - shade atc.

Great tip Charriot.

In respect of horisontal vs vertical mount, it all depends on your energy budget and your priorities, doesn't it?

If you only need top-up charge, the most convernient mount may keep your bank topped up just fine.
If you run a fridge, TV, stereo etc. and draw heavily, and solar is your main re-charge, you may need to prioritise panel orientation and sacrifice deck space or pushpit convenience to get them facing the sun.

Personally I like the idea of being able to deploy more panels when needed at anchor, and take them off when sailing or when stormy weather approaches. So I tend to buy several smaller sized panels. Some of them I just spread around on deck when at anchor, with weatherproof electrical leads. When I move off, they go below.

I do like the idea of flexible panels that you can walk on so you don't have to sacrifice space. But I'm still looking for a robust flexible panel with a good reputation.

About a year ago I read about an an award given for a solar-generating paint. Could be applied to roofs etc, so must be pretty weather proof. Probably not commercial yet but when it comes, it could be an interesting option.