Shade, Shadow and Junk on a Kyocera 185w panel

[jage]

The following is mostly raw footage of my amperage fluctuation as I covered or shaded the panel with various "experimental test objects" to see what would happen. Interesting that you can halve the output with a small piece of cardboard, or zero it by covering less than half the panel. This is all done in full sun, and orientation does seem to matter- although my testing was largely random.

[youtube:vy4l2mjn]

 

[cellularSTEVE]

I am surprised how it drops so much with such a small coverage (i.e. cardboard).

Roof rack shadow isn't as bad as I suspected but a rooftop box will likely make it zero, as shown in the half blanket example.

Thanks for posting this!

steve :c3:

 

[Pntyrmvr]

Jage;

Outstanding experiment. That black tee shirt must have been making 20 amps or volts or whatever!

How much did that panel cost you? Almost 10 amps with no moving parts sure keeps the fridge running.

Regards,

Gavin

 

[cygvan]

does your panel have bypass diodes? if not, i wonder what youd get with them.

 

[docd]

Great experiment. I now have a better understanding of the effects of bird poop on my panels. I need to get up there today!! DocD :l1:

 

[twogone]

Dang! :t4: Ida lost some bets on those tests. Apparently the entire interaction of the panel is required to get voltage. My 15 year old panel really falls off sharply when a little cloud coverage happens. I wouldn't have bet 8" square of cardboard was so severe. Thanks a bunch for some real world understanding of the panels :b5:

 

[Ford_6L_E350]

Shade seems to have less effect than I would have thought. While blocking one cell has a much bigger effect than I would have imagined.

Nice demo. Thanks Jage!

Mike

 

[WVvan-SMB]

Excellent! I love a good experiment. I was really surprised how much of a difference the plastic pipe made if it was laying directly on the panel as opposed to being just above.
The biggest surprise was how you get no amps with a partially covered panel. I wonder if the parts of the panel that are getting no light start acting like resistors so that whatever energy that is being produced by the uncovered panels is being blocked.

I'm just guessing. Is there anyone here on the board who knows about solar cells and would like to comment?

 

[BroncoHauler-SMB]

Well sure it was informative, but incomplete. What's the panel output when the entire solar panel is completely covered? :a2:

Great info, and yeah, surprising results.


Herb

 

[NRL]

Nicely Done.
I would think multi panels would have better results. For example, two panels or even four panels in parallel...

 

[larrie-SMB]

Fascinating. Looks like the bottom line dirt and shade are amp robbers, avoid at all costs. It would be interesting to see this test on other panels from different manufacturers.

One thing I did notice is that the orientation of the shadow seemed to make a difference. At 2:24 to 2:36 the orientation of the shadow changes and the amps are not the same even though the same number of cells are covered. With the cardboard running up and down the amps are 1.8 with one row covered. With the cardboard running across the amps were 3.2 with the same number of cells covered. This must relate to how the individual cells are wired within the panel.

 

[jage]

larrie, I noticed that too, as well as the shadow vs. direct placement on the panel. If you were mounting under a roof rack, orientation might make a huge difference.

I also wonder about the drop to zero, and the bounce back right at the end of the blanket- would the result have been the same from the opposite side of the panel?

Questions for someone else... way to dang hot to be playing on the roof!

 

[macmcintire]

Thank you very much for this experiment. Very interesting. I had heard of how much shadows and other objects block the solar panels, but had no way of visualizing it. Much appreciated Jage!

 

[davidrippberger]

I recall a thread about 5 years ago, perhaps on the old smb-owners list, that, as I recall, indicated glass "kyocera type" panels were more efficient, but far more sensitive to even a very small shadeing, while the thin rubber type panels were less efficient, but far more forgiving of partial shading.

 

[Skywagon-SMB]

Scatter has the flexible panels, 3 I think, and they seem to work pretty well even in partial shade.
Maybe he'll kick in with a report.
Bill

 

[daveb-SMB]

I originally had 3 Solara panels made for the boating crowd. They didn't seem to be as affected as my 2 Kyrocera's but that was 3 smaller panels against 2 larger and the shadowing was from trees. I know the Solara panels are made to work better in dim or shadowed light. My guess is even the Solara's would be troubled with knocking out a line of cells though. From what was posted on the other thread here about solar, it sounded like the Kyocera 135's are set up for handling shadowing but I'd still think they would react poorly when a full line of connected cells are blocked. Just a guess on my part.

 

[Ford_6L_E350]

There is a huge difference between shadowing and blocking cells. In complete tree shadow I typically get about 50% charge (compared to full, direct sun). But, if you have some leaves or other debris on your solar panel you may get closer to 0. Or not, depending on what it blocks.

Mike