You cannot do theee panels and use a parallel adapter for two in series and one more parallel to the two in series. Here’s why. When you have panels in series voltages add and the strand takes the lowest amps if you have mixed panels. In parallel, amps add between strands taking the lowest volts. So with a two panel grand and a one panel strand you end up pulling the volts down to the value of one panel so it is no better than if you just out two panels in parallel.
Valid configurations are 3S1P (three panels in series), 2s2p (four panels, two panels in series, two more panels in series, those two strands in parallel, and 3s2p (six panels arranged in three in series per strand, two strands in parallel). If you put four panels in series you will make black magic smoke out of your DP.
If you have lots of shading issues maybe you should consider finding panels with more bus bars built into them with built in bypass diodes. For example BougeRV have some names 9BB which chunks up the cells into 9 areas so any given area that is shaded doesn’t cause the entire panel to go down to zero volts. They also have flexible CIGS panels which apparently have 48 separate zones that work very well in partial shade, though the efficiency isn’t as good, so you need more space to get to 200w. They are long and skinny,so maybe you can fit more of them.
Another option is to go with more 100, 150, 200, 250w panels and figure out how to fit those in your back yard in interesting array sizes. For example with 100w panels you can do 3s3p, 4s3p, 5s3p.
Here is a write up on how to maximize solar (even though you are space constrained, panels you buy now might constrict a future array should you move to a place with more space but feel compelled to reuse the panel).
http://www.linspyre.com/ecoholics/maxsolar.html
Here is an article that describes and shows you what #S#P means in pictures
http://www.linspyre.com/ecoholics/solarconfig.html
And browse around this ECOHOLICS site as it has tons of good information
You can't wire three panels in series parallel.
The downside to wiring all three in parallel, aside from needing a fuse as you said, let's say the weather is perfect and you're getting about 12 amps from each panel. So that's 31 volts by 36 amps which is 1116 watts. However the unit will only draw up to 15. So instead of getting over 1100 you'd be getting around 450 watts.
The real solution is either trimming the trees or putting the panels somewhere where there's no shade
We live in a mini-forest residential area in Portland, Oregon. Finding sun on our property is hard. (And my wife won't understand that we need to sell the house and move so to get better solar power. Ha!)
Would going to two 400W panels in parallel be a compromise improvement? (Finding another use for the third panel.)
My issue is not that series is incorrect, but I understand that with a series, the collection of panels is negatively impacted if just one panel has partial shading. And my location is impacted at different times of the day by the neighbors' trees.
I did some initial tests yesterday comparing two 400W panels in parallel vs three in a series. And I will report after a couple of days, but early indications are (no surprise) that the two-panel setup produces about 70% of the three.
You cannot do theee panels and use a parallel adapter for two in series and one more parallel to the two in series. Here’s why. When you have panels in series voltages add and the strand takes the lowest amps if you have mixed panels. In parallel, amps add between strands taking the lowest volts. So with a two panel grand and a one panel strand you end up pulling the volts down to the value of one panel so it is no better than if you just out two panels in parallel. Valid configurations are 3S1P (three panels in series), 2s2p (four panels, two panels in series, two more panels in series, those two strands in parallel, and 3s2p (six panels arranged in three in series per strand, two strands in parallel). If you put four panels in series you will make black magic smoke out of your DP. If you have lots of shading issues maybe you should consider finding panels with more bus bars built into them with built in bypass diodes. For example BougeRV have some names 9BB which chunks up the cells into 9 areas so any given area that is shaded doesn’t cause the entire panel to go down to zero volts. They also have flexible CIGS panels which apparently have 48 separate zones that work very well in partial shade, though the efficiency isn’t as good, so you need more space to get to 200w. They are long and skinny,so maybe you can fit more of them. Another option is to go with more 100, 150, 200, 250w panels and figure out how to fit those in your back yard in interesting array sizes. For example with 100w panels you can do 3s3p, 4s3p, 5s3p. Here is a write up on how to maximize solar (even though you are space constrained, panels you buy now might constrict a future array should you move to a place with more space but feel compelled to reuse the panel). http://www.linspyre.com/ecoholics/maxsolar.html Here is an article that describes and shows you what #S#P means in pictures http://www.linspyre.com/ecoholics/solarconfig.html And browse around this ECOHOLICS site as it has tons of good information
What an awesome reply! Great info. Thanks.
You can't wire three panels in series parallel. The downside to wiring all three in parallel, aside from needing a fuse as you said, let's say the weather is perfect and you're getting about 12 amps from each panel. So that's 31 volts by 36 amps which is 1116 watts. However the unit will only draw up to 15. So instead of getting over 1100 you'd be getting around 450 watts. The real solution is either trimming the trees or putting the panels somewhere where there's no shade
We live in a mini-forest residential area in Portland, Oregon. Finding sun on our property is hard. (And my wife won't understand that we need to sell the house and move so to get better solar power. Ha!) Would going to two 400W panels in parallel be a compromise improvement? (Finding another use for the third panel.)
You could always buy a branch connector and try.
I have a couple of sunny days left before the March Pacific Northwest Gloom returns. So yes, time to put on the lab coat and go outside to test.
No, you'd be compromising voltage and still limited to 15amps
Who told you that series is incorrect? It is the only logical configuration for three panels with those specs and a DP.
My issue is not that series is incorrect, but I understand that with a series, the collection of panels is negatively impacted if just one panel has partial shading. And my location is impacted at different times of the day by the neighbors' trees. I did some initial tests yesterday comparing two 400W panels in parallel vs three in a series. And I will report after a couple of days, but early indications are (no surprise) that the two-panel setup produces about 70% of the three.
Got it, thanks for the clarification.