Where To Put Solar Panels?

[Teknav]

AMP Hours...terminology is not widely used in Electrical Engineering textbooks; EE major. AMP (A) is the common unit used.

Mauritz

[noelex 77]

Originally Posted by Teknav

AMP Hours...terminology is not widely used in Electrical Engineering textbooks; EE major. AMP (A) is the common unit used.

Mauritz

EE talk about WattHrs not AmpHrs. The former term is more technical correct, but does not work as well for battery storage for a few reasons:

Battery companies list the capacity in AmpHrs not WattHrs
Measuring electricity consumption in AmpHrs partially compensates for charging inefficiencies.
Many battery monitors will only measure AmpHrs.

Thus you will find most owners talk about AmpHrs, but if writing a technical paper WattHrs would be used.

Amps cannot be used to substitute AmpHrs they are measuring different things.(but often on CF people say Amps when they mean AmpHrs, or. Vice versa)

[skipmac]

Originally Posted by noelex 77

Amps and Amp hours causes the most confusion on CF.
A better analogy of Amp hours is the the total amount of water.

OH, that's what I thought I said or what I meant to say. "How many gallons of water flow through a pipe in one hour" or how many gallons of water (as in the total number of gallons) flow through a pipe during a time span of one hour.

Although I now see a grammar fart where I said how much amps (thinking how much water) when it should have been how many amps.

[zeehag]

as far as placement of panels is concerned---i place mine in the sun ......
i am still trying to design a placement on my boat for my 6 panels.....
so i will eventually place my in the sun panels on a set of 2 biminis and some on coach house roof. we will see what evolves as i continue.

[susswein]

I currently have two 80 watt panels on an arch on my Balboa 27 (8.5' beam trailer sailor). Prior to this I had the same 2 panels mounted on folding mounts on each side of my stern pulpit. The biggest advantage of having them up on the arch is that they continue to generate power while underway, and leave the stern pulpit free to mount a BBQ, rod holders, stern anchor, etc.

[o_q]

Originally Posted by susswein

I currently have two 80 watt panels on an arch on my Balboa 27 (8.5' beam trailer sailor). Prior to this I had the same 2 panels mounted on folding mounts on each side of my stern pulpit. The biggest advantage of having them up on the arch is that they continue to generate power while underway, and leave the stern pulpit free to mount a BBQ, rod holders, stern anchor, etc.

How big are these?

[susswein]

Originally Posted by o_q

How big are these?

I'm guessing about 2' by 4' each.

[familycruisers]

I didnt want aft windage so I put them on the coach top. At anchor they can be raised tilted for optimum sun/angle.

[o_q]

Originally Posted by familycruisers

I didnt want aft windage so I put them on the coach top. At anchor they can be raised tilted for optimum sun/angle.

what's holding up those panels? Did you install it?

[D&D]

Originally Posted by GILow

I believe, within reason, most panels produce much the same power per area of panel, (but I might be wrong)...

We believe you might indeed be wrong. We carry 2 SunPower E20 panels that are 1045 x 1559mm each and their rated output is 327W each, or 200W/sq m. There are many other panels, of course, but one of the most popular would be Kyocera...and their current best off-grid (i.e. suited for marine use) panel promoted in Australia is the KD100-36SX which is 668 x 1500mm for a rated 135W, or 135W/sq m. So SunPower's officially-rated output per square metre is nearly 50% greater than Kyocera.

As well (and perhaps most importantly for marine use) the SunPower panels excel in less-than-laboratory conditions (low sun or cloudy) of the type that is far more common than the direct overhead conditions assumed in achieving rated outputs.

So when we were looking to 'go solar' on our vessel, SunPower panels were (and are still) a real 'category-killer' for output per limited area.

We happily admit that we are now (after our installation and being then amazed at the extent of our solar power output) a SunPower Partner...and we would be happy to assist any vessel in Australia considering upgrading to SunPower marine solar power.

Anyway, here's our installation...


Our wide beam was the key for us, of course, but a single SunPower panel installation on a monohull would still produce better output than any other alternative.

[o_q]

Originally Posted by D&D

We believe you might indeed be wrong.

Hey, don't you work for these guys?

Originally Posted by D&D

We carry 2 SunPower E20 panels that are 1045 x 1559mm each and their rated output is 327W each, or 200W/sq m.

Are you well acquainted with marine solar panel installations? If so, given your knowledge of your brand, what do you suppose I can reasonably put on a Catalina 27?

Originally Posted by D&D

SunPower's officially-rated output per square metre is nearly 50% greater than Kyocera.

Originally Posted by D&D

As well (and perhaps most importantly for marine use) the SunPower panels excel in less-than-laboratory conditions (low sun or cloudy)

I'm curious as to how this is measured.
You claim 2 superior attributes:

1. Higher output in lower light.
2. Higher output per square meter.

Is the 2nd a result of the function of the two, or do they augment?
In other words: Is the claimed "50% more power" only possible because of its lower light efficiency, or are they separate things?

Anyway, here's our installation...
Attachment 65793

Our wide beam was the key for us, of course, but a single SunPower panel installation on a monohull would still produce better output than any other alternative.

Can you go into detail what you got going on there? (I'm a boat n00b)

[familycruisers]

It was a custom mount that my mind and brother in laws machine shop created. They are two Sun World panels. They are American made as well as the Midnite solar controller I use. Very pleased with this setup.

[Rhapsody-NS27]

I have a 27' boat too and my stern rail is curved so I've been looking at getting a couple of these that mount a 140W panel between stanchions. Might be something to consider too.

Stanchion Mounting Kit with 140 Watt Panel - e Marine Systems

[D&D]

Originally Posted by o_q

Hey, don't you work for these guys?

We are a 'SunPower Partner'; that means we advise and assist on SunPower panel installations. We are not, however, a big operator for SunPower. Far from it. Ours is a 2-person business that arose out of a love of cruising and a desire to help others to find new ways to cruise in comfort. So we tend to work fairly exclusively within the cruising community...and we give excellent terms to fellow cruisers for any products we provide.

Originally Posted by o_q

Are you well acquainted with marine solar panel installations? If so, given your knowledge of your brand, what do you suppose I can reasonably put on a Catalina 27?

What's on your stern now? Like others on this thread, we believe the best panel position is well aft, but what you can do on your vessel will depend on what's there now, as well as your willingness to entertain new fabrication on and around your stern, or elsewhere. If you're willing to look at the fabrication required, you may well find a single SunPower E20 panel mounted off your stern would be your best choice...and you will definitely be pleased with its output.

Originally Posted by o_q

You claim 2 superior attributes:

1. Higher output in lower light.
2. Higher output per square meter.

Is the 2nd a result of the function of the two, or do they augment?
In other words: Is the claimed "50% more power" only possible because of its lower light efficiency, or are they separate things?

Definitely separate things; that was our point above.

The 'headline' rating for a panel is determined under basically lab conditions (overhead light) so that it can be viewed as an apples-to-apples comparison between competing panels. SunPower's lab-rated output is simply the best available.

The non-lab performance of a panel is a subject of much conjecture and differing views, although there are several measurements often used and quoted. There's a reasonable discussion of all this at http://www.cruisersforum.com/forums/...ml#post1291809 so we won't go into it again here, but suffice to say that SunPower's non-lab performance is excellent, the best available according to at least one independent study.

For marine installations, the very important point about non-lab performance is that it is just as important as the rated output. After all, the sun tends to spend a fair amount of time either relatively low in the sky, or behind clouds...and those are times when you will still want to see output from your panels! We can certainly say from our own experience that our panels output under limited light conditions is amazing.

[familycruisers]

I'm back to float by 9am on sunny days, 12pm to 3pm on cloudy to rainy days. The trick is in the higher voltage grid tie panels coupled with a good mppt controller.