2 arrays power generation

[deats01]

I have recently had a 5kw system installed. 12 solar panels. 2 separate arrays. 8 panels south facing 4 west. Here’s the question… is it generating enough…

The attached file shows the power generated on the 8th March, a beautiful sunny day.

Am I right in thinking the PV1 and PV2 are the separate arrays? If so one array of panels have barely generated anything? (I assume the 4 West).

Surely this cannot be right? Especially when it was a clear day with sunshine all day.

How can I check further and why would the west generation be so low?

Many thanks

[Dave Foster]

Yes PV1 & 2 are your seperate arrays - PV1 looks ok for 8 panels of around 400 watts at this time of year, PV2 looks low but at this time of year for west facing panels the suns elevation is rapidly falling from mid afternoon.

If the there are any trees or houses on the skyline they can interfere with solar production, as can shadows from gable ends, chimneys or similar - all of which will be worse at this time of year.

On a clear sunny day, take pictures of the array of 4 panels every hour from 2pm which should hopefully show any shadows falling across them - if a single panel is shaded across the bottom (or side) of the panel it can have a throttling effect on the entire array.

Just to check can you post the traces for PV1 & PV2 voltage as that will confirm the number of panels fitted on each.

[deats01]

Hi Dave, many thanks for your response. It’s sunny today so I’m hoping it’ll be ok later to check the shade etc. The scaffolding is still up and that may be shading a little, I’ll check. Other than that there is nothing blocking the sun until the sun goes down.

Attached is the Voltage for both arrays

Many thanks

[Dave Foster]

Your PV2 volts looks ok and suggests the sun is effectively on them from 1pm-4pm.

It doesn’t take much in the way of a shadow if it crosses the whole panel and a scaffold poll could do it, particularly if the panels are mounted horizontally as it only has to cross 2/3 rd’s of the panel - at low sun elevation you can’t beat looking at the panels to watch shadows passing.

If you do have shadows from low lying buildings, trees, roof lines etc.. - it is best to fit Tigo optimisers now whilst the scaffold is up, particularly with only 4 panels in an array as one panel can throttle the others and it’s easier to shut down the array.

[deats01]

Thanks Dave, it looks as though the scaffolding poles could be the reason. Unfortunately it wasn’t that sunny this afternoon so I will check again later in the week and take some pics.

Thanks for all of your help.

[deats01]

Hi, the suns shining today, clear blue sky’s, so I took some pics of the roof (west panels) and solar that’s being generated at that time. As you can see there is some shading from the scaffold poles but would it really stifle the generation this much?

Thanks and I appreciate your feedback. The scaffolding is due to be taken down in the next week. I guess I won’t know until that happens if it has such an effect.

[Dave Foster]

Yes quite likely, because the main panel is in full sunlight those shadows are across the entire matrix so the panels built in bypass diode will try to remove the parts of the panel that are not performing (each panels is split into sub panels with bypass diodes on each).

Ironically like this you will probably get more power output on a bright cloudy day.

I think once the scaffold is down you should have normal output.

[deats01]

Thanks Dave for your reply, I’ll proceed with them taking the scaffolding down and see how it goes.

Many thanks