dirty solar panels, warm weather, lower power output? 22 June 2022 at 2:54PM in Green & ethical MoneySaving 52 replies 1.5K views

Mikeyboy01443

hi guys,

had solar installed about a month ago - at points i have seen my solar generate as high as 7.5kw at any one moment, but at the moment the highest i have seen them hit is about 5.7kw - clear skies, is the warmer weather affecting my output?

or we also had some kind of dust / sand storm and everyones cars look filthy, my panels look a bit dirty and dusty too, would this also be affecting output? have you guys noticed any difference in performance?

2nd_time_buyer

It is almost certainly not dust. Some people report never having cleared their panels for many years without a significant reduction.

The warm weather will affect output but it seems unlikely that the effect would be as large as reported for only a <10 degree variation in ambient temperature - are you sure it was the same time of day? What was the wind like as the heat will build up a lot more on a windless day? are you currently under hazy sunshine?

You can get largish spikes where the panels have been under cloud all day (so cool) and the sun peaks out from behind a cloud. I presume that was not the case when you recorded the previous maximum(?)

There is the slight possibility that one of your strings has gone down to the inverter. Do you have multiple strings of panels going into the inverter? 

Mikeyboy01443

thanks for the reply - it could have been a spike when it hit the max, and then dropped down, whereas last few days it has been generally clear skies so i've had a consistent curve of PV power generation... i can post up some example outputs, it could just be normal but im definitely not seeing as high as some othe peaks i have hit before...

i doubt it is one of the strings down as i would presumably lose everything on that string? so would be half my output rather than just a bit lower? its hard to know what the weather was like as often i am not home, im just looking at the app / web portal to see output....

it has only been in a month so i am still learning what is normal behaviour...

2nd_time_buyer

Mikeyboy01443 said:

thanks for the reply - it could have been a spike when it hit the max, and then dropped down, whereas last few days it has been generally clear skies so i've had a consistent curve of PV power generation... i can post up some example outputs, it could just be normal but im definitely not seeing as high as some othe peaks i have hit before...

i doubt it is one of the strings down as i would presumably lose everything on that string? so would be half my output rather than just a bit lower? its hard to know what the weather was like as often i am not home, im just looking at the app / web portal to see output....

it has only been in a month so i am still learning what is normal behaviour...

Yeah, I would not worry too much. You might be better off comparing the daily output on comparable days which is usually a more robust measure.

You are right about the strings unless you have a string with only a few panels on.

Exiled_Tyke

At this time of year the best instantaneous readings I see are usually about 3/4 of maximum. Once in while, at the right time of day, cool air and perhaps a passing cloud to help I'll see something around max.  Note, my split system (I'm only referring to my first installation as I don't have any monitoring on the additional) has a part to play in this, so maximums are expected to be rare for me. 

Magnitio

Today's temperature, intense sun (at least where I am) and lack of a cooling breeze will have an impact on output. Typical solar panels have a temperature coefficient of -0.25 to -0.5% per degree centigrade. They could easily be 20 degrees hotter today than when there is a cool breeze or intermittent sun. That equates to between 5% and 10% reduction in output. As mentioned above, intermittent cloud can also result in higher spikes in output due to edge of cloud effect.

diystarter7

Sorry, but reading this just makes me cringe as I hate solar panels as they make the area look run down as do wind turbines, dirty or not.
I'm same with those tv dishes.

Re the sun pannels, watch out for the dead pigeons under them or roof leaks as it cost  lot more to get the roof seen to etc.

EricMears

diystarter7 said:

Sorry, but reading this just makes me cringe as I hate solar panels as they make the area look run down as do wind turbines, dirty or not.
I'm same with those tv dishes.

Re the sun pannels, watch out for the dead pigeons under them or roof leaks as it cost  lot more to get the roof seen to etc.

Yes and building houses rather than leaving road (or even field) empty probably offends you too.

I assume you do live in a cave somewhere ?

Alnat1

Don't know where he lives but he pays around £300 a month for his energy. Probably because he hasn't got solar panels (with or without dust) cos then he might only be paying £100.

Mikeyboy01443

diystarter7 said:

Sorry, but reading this just makes me cringe as I hate solar panels as they make the area look run down as do wind turbines, dirty or not.
I'm same with those tv dishes.

Re the sun pannels, watch out for the dead pigeons under them or roof leaks as it cost  lot more to get the roof seen to etc.

What an odd thing to say lol if you hate solar panels and everything about them,  why reply in a thread about them? 
Or are you doing this for every thread mentioning solar panels? 

Exiled_Tyke

diystarter7 said:

Sorry, but reading this just makes me cringe as I hate solar panels as they make the area look run down as do wind turbines, dirty or not.
I'm same with those tv dishes.

Re the sun pannels, watch out for the dead pigeons under them or roof leaks as it cost  lot more to get the roof seen to etc.

This isn't the place. the Op asked for advice not opinion on aesthetics.  I'm sure we could run a poll of PVer's on experiences of dead pigeons & roof leaks but frankly there's no point.   Are you sure that Green & Ethical is the right place for you?