Are Solaredge Optimisers Always Worthwhile?

Dave_Fowler

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system? I see different things online, some say you lose up to half to 2/3 of your total output from that array. But then others talk about bipass diodes which means that you just lose the panel with shade 

Be interested to see if anyone has tested the theory on here!

The PV panels on my house roof are split into two strings. One string has a panel which is badly shaded by the chimney for most of the morning. 
I am able to monitor the output from each string using the inverter software. When the panel is in the shade there is a drop in the output from its string which amounts to just the output from that panel. 
Virtually all PV panels have bypass diodes so there will be no affect on the string other than that directly caused by the reduction of the shaded panel.  If there are bypass diodes it is incorrect to say that the entire string output will 'killed' by the panel that is shaded.
Dave F

Jonboy1889

Dave_Fowler said:

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system? I see different things online, some say you lose up to half to 2/3 of your total output from that array. But then others talk about bipass diodes which means that you just lose the panel with shade 

Be interested to see if anyone has tested the theory on here!

The PV panels on my house roof are split into two strings. One string has a panel which is badly shaded by the chimney for most of the morning. 
I am able to monitor the output from each string using the inverter software. When the panel is in the shade there is a drop in the output from its string which amounts to just the output from that panel. 
Virtually all PV panels have bypass diodes so there will be no affect on the string other than that directly caused by the reduction of the shaded panel.  If there are bypass diodes it is incorrect to say that the entire string output will 'killed' by the panel that is shaded.
Dave F

thanks Dave, that’s helpful- so even your non SE array just sees the loss of the panel that is shaded as opposed to the whole array? This is consistent with what I’m seeing, when the corner panel of my 8 panel 2.4kw SSE array starts to be shaded I lose 200 watts or so, but by that stage the sun is well west so the whole array is only generating about 1.2kw, so seems to add up that that individual panel loses power and not the rest. Obviously still not ideal losing the whole panel for a bit of shade, but better than the 60-70% loss of the whole array I’ve read in some places.

I guess optimisers/micro inverters mean that the rest of the shaded panel works a lot more effectively?

Jonboy1889

The very faint line is 4:10 when my SSE panel starts to be shaded, have a WSW which kicks in well before then- a small drop at 4:10 but not too different to the rest of the decline as the sun comes round and basically isn’t shining on SSE panels at all/is just getting lower.

weirdly altho the drop is sharper at the end of the day, it seems to generate more in the second half than the first half (less white space at least)- not sure if this is just the time of year/sun more intense later but obviously sets quickly (I’ve got tree shading very early morning as well so probably affects the steepness of the morning)

QrizB

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system?

I've got an experimental, moveable ground array that consists of four 240W, 60-cell panels connected as a single string to a Growatt mini 1000S inverter.

At the end of April I noticed that it was in full sun EXCEPT my shed was shading three cells on one panel. The total output from the array was about 80 watts.

I moved the array 100mm so it was out of the shade

*** Edit: I misremembered. Rather than move the array, I crawled underneath it and re-wired it as a three panel string, omitting the shaded panel. ***

... and output rose to about 480 watts, a six-fold increase.

And that was due to shading of three cells, on one panel with sixty cells, in a string of four panels.

So yes, I would say that shading can have significant impact on output.

Edited to add photo. shading at top-right:

Jonboy1889

QrizB said:

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system?

I've got an experimental, moveable ground array that consists of four 240W, 60-cell panels connected as a single string to a Growatt mini 1000S inverter.

At the end of April I noticed that it was in full sun EXCEPT my shed was shading three cells on one panel. The total output from the array was about 80 watts.

I moved the array 100mm so it was out of the shade and output rose to about 480 watts, a six-fold increase.

And that was due to shading of three cells, on one panel with sixty cells, in a string of four panels.

So yes, I would say that shading can have significant impact on output.

I see your panels were installed in 2012- I wonder if older panels don’t have the technology to compensate for shading? But newer ones with bipass diodes do?

QrizB

Jonboy1889 said:

QrizB said:

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system?

I've got an experimental, moveable ground array that consists of four 240W, 60-cell panels connected as a single string to a Growatt mini 1000S inverter.

At the end of April I noticed that it was in full sun EXCEPT my shed was shading three cells on one panel. The total output from the array was about 80 watts.

I moved the array 100mm so it was out of the shade and output rose to about 480 watts, a six-fold increase.

And that was due to shading of three cells, on one panel with sixty cells, in a string of four panels.

So yes, I would say that shading can have significant impact on output.

I see your panels were installed in 2012- I wonder if older panels don’t have the technology to compensate for shading? But newer ones with bipass diodes do?

These aren't my roofop panels; this is just a plaything!

ABrass

QrizB said:

Jonboy1889 said:

QrizB said:

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system?

I've got an experimental, moveable ground array that consists of four 240W, 60-cell panels connected as a single string to a Growatt mini 1000S inverter.

At the end of April I noticed that it was in full sun EXCEPT my shed was shading three cells on one panel. The total output from the array was about 80 watts.

I moved the array 100mm so it was out of the shade and output rose to about 480 watts, a six-fold increase.

And that was due to shading of three cells, on one panel with sixty cells, in a string of four panels.

So yes, I would say that shading can have significant impact on output.

I see your panels were installed in 2012- I wonder if older panels don’t have the technology to compensate for shading? But newer ones with bipass diodes do?

These aren't my roofop panels; this is just a plaything!

What panels are they, this topic is interesting.

Jonboy1889

QrizB said:

Jonboy1889 said:

QrizB said:

Jonboy1889 said:

Has anyone actually tested the impact of shading one of their panels on a single array to see what impact it has on production? For a recent system?

I've got an experimental, moveable ground array that consists of four 240W, 60-cell panels connected as a single string to a Growatt mini 1000S inverter.

At the end of April I noticed that it was in full sun EXCEPT my shed was shading three cells on one panel. The total output from the array was about 80 watts.

I moved the array 100mm so it was out of the shade and output rose to about 480 watts, a six-fold increase.

And that was due to shading of three cells, on one panel with sixty cells, in a string of four panels.

So yes, I would say that shading can have significant impact on output.

I see your panels were installed in 2012- I wonder if older panels don’t have the technology to compensate for shading? But newer ones with bipass diodes do?

These aren't my roofop panels; this is just a plaything!

Yes would be interested to know the brand and age of the panels 

QrizB

Jonboy1889 said:

QrizB said:

These aren't my roofop panels; this is just a plaything!

Yes would be interested to know the brand and age of the panels 

These ones, purchased second-hand a couple of years ago:

Jonboy1889

I wonder if that’s why shading affects it so much,
the age and technology of the panel. Has anyone else has done a similar test on their panels? I see the spec for mine says “Less shading effect”, whatever that means. It also says they each have 3 diodes which probably helps.