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Best solar panel for shading?

pfwag

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Jul 6, 2020
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Want to build a 1000W system for a cabin in the mountains. Depending on time of year, it gets 2-3 hours of direct sun with 2-3 of tall tree shading on either side of that with full shade thereafter. Since I'm not going to cut down the 100 year old trees, what's the best 250W+ panel that handles shading? I've heard that Canadian Solar panels uses split cells with more columns and that there's a bypass diode on each column and that Sunpower has a bypass diode across each cell. Comments/suggestions?
 
Even for panels "designed" for it, partial shading on a panel really hurts its output as well as any panels in series with it. All panels have bypass diodes to some degree and panels with multiple parallel strings of cells are better, but you can still count on losses. The benefits of any shading tolerant panels may not justify their increased cost.

The best way to deal with it is to favor paralleling panels whenever possible so shading of one affects others none at all.

You need to OVER PANEL to ensure you harvest enough energy in the few hours you get.

Alternatively, locating your panels remotely to a location that gets more sun may be a better solution.
 
What's wrong with cutting down a 100 year old tree? In the Northwest, we planned on a 100 year rotation for forested areas. So, 100 years is just about the right time for tree cutting.

Alternatively, with a MPPT controller (a real one) you could wire your panels in series for higher voltage, and string them out 100-200 feet away from your location. In my own systems, I wire my arrays for 120VDC, and transmit that power about 125' to the charge controller. With 10 gauge wire, I see no voltage drop over that distance at 120V. I'm wiring four 250W panels in series, exactly what you are talking about. I'm using Midnight200 controllers for my systems.

I installed my panels on rotating ground mounts, and I've measured 6.1kwh in the first week of February, by tracking the sun over the course of the day.
 
Even for panels "designed" for it, partial shading on a panel really hurts its output as well as any panels in series with it. All panels have bypass diodes to some degree and panels with multiple parallel strings of cells are better, but you can still count on losses. The benefits of any shading tolerant panels may not justify their increased cost.

The best way to deal with it is to favor paralleling panels whenever possible so shading of one affects others none at all.

You need to OVER PANEL to ensure you harvest enough energy in the few hours you get.

Alternatively, locating your panels remotely to a location that gets more sun may be a better solution.
The remote location is out. Cabin has tall trees and a steep mountain on the other side. Don't have room for more than 3 panels on the cabin roof - the part that is facing almost the perfect direction and has a slope just 2 degrees off optimum - so that limits over-paneling and for 3 panels any extra cost is not that big of deal anyway. Since I won't be cutting down the trees, it appears that the half/split cell panels are a bit more tolerant of shade with Sunpower having a bypass diode across each cell which should make it the most shade tolerant. They the only ones that do that? I've seen some ~330W Canadian Solar panels around at great prices. Any recommendations on a dealer/distributor that will sell 3 Sunpower panels? I have no idea what they cost.
 
What's wrong with cutting down a 100 year old tree? In the Northwest, we planned on a 100 year rotation for forested areas. So, 100 years is just about the right time for tree cutting.

Alternatively, with a MPPT controller (a real one) you could wire your panels in series for higher voltage, and string them out 100-200 feet away from your location. In my own systems, I wire my arrays for 120VDC, and transmit that power about 125' to the charge controller. With 10 gauge wire, I see no voltage drop over that distance at 120V. I'm wiring four 250W panels in series, exactly what you are talking about. I'm using Midnight200 controllers for my systems.

I installed my panels on rotating ground mounts, and I've measured 6.1kwh in the first week of February, by tracking the sun over the course of the day.
The cabin sits in a hollow in the forest next to a steep mountain side. It's 2 stories and the upper half of the roof is the only area around within a quarter mile or so that gets the sun that I outlined above. Even the mountainside is covered with trees. Oh, and this is in Colorado so a 100 year old tree is a big deal. Might even be older than that... base of the trunk is ~3 feet in diameter. That's not big in the Northwest but is huge in Colorado. And 5-8 years ago I cut down about 30 beetle-kill trees near the cabin but now I'm 71 and too damn old to be cutting trees down to get a little more sunshine when I can hopefully just pay a little more for panels that will tolerate the shade. And forget needing any power in February... the cabin is only accessible from the middle of May to middle-late October, depending on the first snow. Only way to get there in the winter is hike in 7 miles along the railroad track and then trudge through 1/2 mile of snow. And freezing water early in the spring when the river overflow its bank. I will take a look at the Midnight200 though. Thanks for the tip.
 
The cabin sits in a hollow in the forest next to a steep mountain side. It's 2 stories and the upper half of the roof is the only area around within a quarter mile or so that gets the sun that I outlined above. Even the mountainside is covered with trees. Oh, and this is in Colorado so a 100 year old tree is a big deal. Might even be older than that... base of the trunk is ~3 feet in diameter. That's not big in the Northwest but is huge in Colorado. And 5-8 years ago I cut down about 30 beetle-kill trees near the cabin but now I'm 71 and too damn old to be cutting trees down to get a little more sunshine when I can hopefully just pay a little more for panels that will tolerate the shade. And forget needing any power in February... the cabin is only accessible from the middle of May to middle-late October, depending on the first snow. Only way to get there in the winter is hike in 7 miles along the railroad track and then trudge through 1/2 mile of snow. And freezing water early in the spring when the river overflow its bank. I will take a look at the Midnight200 though. Thanks for the tip.

That is quite a location
 
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