Despite some viewpoints that suggest the optimal orientation is always due south I tend to agree with your observation. Recently I saw several examples of that while driving the I5 in Central California. These were all ground mounts that had no physical constraint on orientation. I don't know if these were powering some agricultural pumps or nearby commercial building because there were a variety of both.
Most of the panels in these installations were facing south but up to 25% were facing west. Perhaps it was more favorable TOU rates that was driving this orientation or the owners own use. These all appeared to be grid tied and none were larger that 100 kiloWatts based on my rough count of panels and/or sq. footage.
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You have some very good comments ... let me add another. ASSUMING your layout supports it, you can get greater harvest by pointing one of the 2 panels somewhat east of south, and one somewhat west of south. You'll have to do the research based on your conditions and location.Leave a comment:
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You're pretty much correct. But it may not be exactly like you're thinking.
First, the IQ7+ is not 97% efficient at maximum power. It may be 97% efficient at some moderate power but less at full power. They specify it as 96.5% EN 50530 (EU) weighted efficiency or 97% CEC weighted efficiency, which means sometimes higher and sometimes lower. 95% at full power may be more realistic.
The panels you mention only put out 205 watts when new and at standard test conditions. At hotter temperatures, lower light or other conditions, output will be less. With time, they will reduce output, roughly 1% per year, give or take.
So what happens in real life? Let's assume a sunny day, no clouds, no trees and nice, cool temperatures. In the morning, the sun begins to rise and you get a little power. As time goes on, you get more power and more power, until high noon, when the panels are capable of their full output. Then, it reverses and the output starts to decay.
Between 10AM and 2PM, give or take, the panels are capable of putting out more than 160 watts, and you're not using them to their potential. Earlier and later, panel capability is less and your inverter is not limiting you. You'll see a curve something like this (note that this is not a curve of your panels and inverter, just a typical plot of someone's system):
lost-energy.jpg
The area in the blue bars represent the power coming out of the inverter. The area of the top red "plate" represents energy that you could have had, if the inverter were larger. Judge for yourself with your particular graph, but in many cases, it isn't a lot of energy lost.Leave a comment:
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Yes, the IQ7+ specs say 235-440W panels.
Wiring is not an issue, 2 panels in series into one inverter. I am working on the design for electrical approval right now, that is why I am asking.Leave a comment:
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The specs for the IQ7 should tell you how much panel wattage it can handle or if you can wire in more than one panel.
The IQ7+ may be limited to just under 300watts so using 2 x 200 watt panels would be a waste.
Second, how do you plan on wiring that IQ7 to? If you try to go with a grid tie system you really need to first get approval from your POCO.Last edited by SunEagle; 07-30-2020, 06:47 PM.Leave a comment:
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Using 2 panels on one micro inverter (numbers not adding up)
I am looking at using two 205watt 18.2v panels in series per IQ7 Plus micro inverter. (I already have the panels)
However, in looking at the max continuous output some #s don't add up.
IQ7+
(Assuming peak performance of my panels)
Panels
(205W * 2) *.97 efficiency for inverter = 389.5W
Inverters IQ7+
recommended module pairing 235-440W
max continuous output - 1.21A for 240V
1.21A * 240V = 290.4W
Will loose out on about 100W of power during peek output if I do this configuration?
I wish the iQ8's were out, anyone know what the output for those will be?
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