Morning,
Had my AIO and panels fitted late November, and have been wondering about shape of the PV generation - would have expected to roughly follow a bell curve (as the various solar forecasts I’ve looked at would suggest), but quite consistently I see PV generation dip daily to around 400W around 12:00.
The regularity / consistency would tend to suggest not linked to cloud cover - is this expected behaviour? In the process of gathering similar screen shots to send to installer, but just wanted to ask what others with more experience would think please?
Live in Scottish Borders, panels facing East and West (panels are about a 60/40 split between front and rear of house), no shading from trees or neighbouring properties
Is this one peak for the West string and one peak for the East String?
The GivEnergy cloud app (givenergy.cloud) let’s you break down the power output of a solar system to each of the strings:
Select the “Power Graph” widget.
Select the menu carrot on the right hand side
select “String 1 Power” and “string 2 power” from the menu. (deselecting everything else makes this clearer)…
…helpfully on my system string 1 power shows in light yellow and string 2 power shows in a more solid/dark yellow, and as both of my strings point in the same direction they are hard to differentiate, but they are different.
Will be interested to know if this is a correct diagnosis or if something else is going on
good luck
Dave
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Thanks Dave.
Did wonder about that, but the forecast models I’ve looked at sum both arrays into one profile, would there be such a marked difference in the peaks and then such a dramatic flat spot in the middle? Whilst I’m seeing these two peak profile more often than not, I do occasionally see the bell curve with a single peak that I’d expect to see.
Unfortunately the PV inverter isn’t a GE one, and GE gateway only reports the single combined PV input from the inverter - and the installer didn’t install the data collector on the PV inverter, so I can’t monitor both strings independently of the GE app / portal.
I’ve gone back to the installer to ask about the profile I’m seeing and to have the PV inverter data collector installed.
Suppose I was hoping to see if others have seen a similar profile and this is expected behaviour for the time of year etc / if I’m misinterpreting something in what I’m seeing / if there is something physically wrong with the installation :-)
Thanks,
Peter.
Peter, Is it not just geography?
Sun rising in E generates from set one, moves to maximum radiated power and highest angle around midday (when both sets receive just glancing rays and therefore less power) then sets in W delivering afternoon power to set two.
I would have anticipated a double peaked distribution, though you have seen a ‘normal’ bell curve which is more surprising.
With low sun angles at this time of year I assume there is never any shading from trees etc.
Thanks,
I was wondering about it, but I would have expected the timings to move over the last two months?
Was just surprised at how steep the dips were between the peaks - but I don’t have any wider experience to compare what I was seeing against.
Will be interesting to see how it performs over the summer in comparison 
Quite possibly unnecessarily overthinking it all - the installation process wasn’t that great, so I haven’t got full confidence with the system yet.
End November and end January either side of the December [20 Th?] minimum so I guess the change would be small. Mine doesn’t do much with in this period with cloud, rain, and the very occasional low sun; and we’re in the South with a south facing roof. Still you have summer in the Borders to look forward to.
Thanks.
Was expecting huge volumes of export at this time of year, but was more the two peak shape I was curious about as it wasn’t consistent behaviour.
Although now I’m thinking about - could the days with a normal, single bell curve have just been one side of the roof delivery?
Definitely now overthinking this and will wait with eager anticipation to nerd out on the spring and summer delivery numbers 
The amount of overlap of the East and West peaks of generation will also depend on the slope angle of your roof.
If the roof is a steep say 60 degrees then there will be significant shading of one side in the morning and evening, whereas a shallower 30 degrees will have good generation from both during the middle of the day.
Here is a snapshot from my East/West system before I swapped out the inverter to GivEnergy. This has the same 6 East panels and 10 West panels as I still have on roughly 30 degrees roof slopes for a near perfect solar gen day in January 2023.
The red line is the total power from both strings.
Thanks Simon - this is exactly the comparison that I was hoping to find!
10 panels face West and 7 face East, roof is 60 degrees
No worries.
Here is the equivalent GivEnergy chart from a few days ago. Not quite the same perfect solar gen as on 20/01/2023 and yellow on yellow for each string power does not provide quite the same clarity.
I know that GivEnergy are also working on a “Solar Forecast” as well on the webpage ( can’t get mine working )
But I use the free Solcast service to do a calculation so I can compare how the forecast vs generated is - and as you know the Degree of your panels you put that all in
I have Rear SW facing and front NE facing panels
I got the Azimuth calcs from here : https://www.suncalc.org/ and to get the reverse Azimuth either + or minus 180 :-)
I use the Solcast API forecast on the GE cloud dashboard , but it can be a bit intermittent - frequently fails connect or loses all credentials.
Will be interesting to see what the summer brings 
