Panels and "Permanent Shade"

[JTS]

I am looking to install one or two panels on a rack system. For practical reasons I would like to place the panels "under" the crossbars of the rack (1in x 2 in aluminum extrusions). As such, there would be 3 extrusions going across the width (not length) of the panel and shading select cells permanently. I would only ever be able to accept about 40 watts in my system (I have a Jackery with obvious limitations — the watt input, as Will notes, maxes at 40), and could over-panel the Jackery by going with a 100 or 200 watt panel. So, the question—if I put up a 100 or 200 watt panel that is in some permanent shade, would the panel be able to generate my modest 40watts (assuming, of course, some good sun).

The question, really, is how shade affects these panels, when it is consistent and permanent.

 

[SCClockDr]

I would avoid all shade as I would avoid placing a pillar midway in front of my garage door.

 

[Deleted member 783]

To answer your question, yes, if there's just one panel, 40 watts should be no problem with that amount of shade.. If more than one panel, be sure to wire them in parallel, as this configuration is better than series in partial shade.

 

[JTS]

I would avoid all shade as I would avoid placing a pillar midway in front of my garage door.

That was not the question, was it.

 

[SCClockDr]

That was not the question, was it.

Permanent & consistent shade usually reduces power production by a greater degree than the percentage of area shaded permanently with predictable consistency. As I understand it one instance of shading that crosses the width of a single panel will impede production for the entire string.

 

[JTS]

Right — as I understand it, that is the case. The question, therefore, is whether or not anyone actually has some first hand knowledge about watt output if one does indeed do it. In my application, there are good reasons for doing it (so you can follow, think analogically about an 8 car garage that needs a pillar mid span). I get it is not optimal for wattage output — we all agree on that. What I want to know is if one could still get a reliable 40 watts from a 200 watt panel in such an application. The question is not that complicated.

 

[JTS]

To answer your question, yes, if there's just one panel, 40 watts should be no problem with that amount of shade.. If more than one panel, be sure to wire them in parallel, as this configuration is better than series in partial shade.

Cool, thanks... that is helpful.

 

[Deleted member 783]

Right — as I understand it, that is the case. The question, therefore, is whether or not anyone actually has some first hand knowledge about watt output if one does indeed do it. In my application, there are good reasons for doing it (so you can follow, think analogically about an 8 car garage that needs a pillar mid span). I get it is not optimal for wattage output — we all agree on that. What I want to know is if one could still get a reliable 40 watts from a 200 watt panel in such an application. The question is not that complicated.

I have experience, thats where my answer comes from. I foolishly mounted a panel that was partially shading another all last summer.

The shade ONLY affects the whole string if the string is wired in series. In parallel, it only affects the shaded panel.

 

[SCClockDr]

 

[Supervstech]

I don’t know.

You say, a 100 or a 200 watt panel... meaning you don’t have the panel yet...

Why not get a 50 watt panel?

 

[Rider]

Hasn't there been a lot of discussion here about shading causing hot spots and premature panel failure? Should that be considered? @Supervstech idea of getting a smaller, more appropriate panel would be the way to go.

 

[Deleted member 783]

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