My solar array doesn't seem to generate enough energy

[agybag]

Hi,
I've recently had a 4KW PV array fitted in March this year however I don't believe it's producing the expected results. Yesterday 29/06/2019 was the hottest day so far with cloudless skies and the system at noon peaked at 2.2KW. I would expect to achieve around my peak which is set at 3.8KW. Is my system faulty and should I have the installers check out the system for any possible issues or am I expecting too much from the system ?

 

[agybag]

242V should be ok. I would expect the inverter to have its upper voltage set at about 250V

OK thanks, I'll speak to the installer when he calls in on Friday as I've lost the meter flashing red light and the solar dropped out completely for a full day on Monday. I do appreciate all the help that's been given and I'll let you know the outcome after the engineers visit.
Regards
John

 

[JimmyTheJock]

I really would not get excited about seeing 242.5V as my supply here at home is presently at 252V which is not unusual as I'm only some 25m from the local 11kV/415V distribution Tx on a sunny day with (probably) very little load on it.
From experience that voltage will drop substantially on a cold winter night when people around start loading it up.
My solar 3.76kW (max) array normally peaks at around 3.4 - 3.45kW on a cool sunny day so about 92%.
I would however be concerned if a 4.41kW array is only peaking at around 2.2kW. I presume you have more that 1 inverter (I would expect 2) so can you interrogate them and see if they are both delivering roughly the same power. You would normally split the feed from the panels 50/50 between them. Is it perhaps 1 inverter that is not functioning properly? Do you have software to interrogate them?
As mentioned earlier you will see a drop in efficiency as pv panels get hot; the temperature coefficient (pMax) will be given in the data sheet but will normally be around 0.4 - 0.5% which means for every +1degC in temperature rise about the nominal (normally 25C) their output will fall by around 0.5%. Just the fact they are operating at all will cause their temperature to rise and their surface temperature will typically be well about the measured air temperature.
They are new so you would not expect degradation yet but be aware as they age the output will fall further. Most manufacturers will specify a maximum at (say) 10 & 20 years and that may well be 10% & 20% as around 1% fall in output per year of operation is fairly typical.
Hope you can resolve the problem without too much hassle but my first port of call would be the installer!

 

[agybag]

HI all,
I had the installer here today and sure enough there's a fault with the inverter. The engineer could not fix and has passed it on to his superiors, I'll keep all concerned informed of the outcome, the system has been switched off for safety reasons as the unit was continually making a buzzing noise.
Regards

 

[Steve888]

Hello the best way to prove the energy production is to use optimisers or a system to measure ac and Dc production. You also have to check if the panels are genuine. I had cases where peopled have been cheated with fake labels....be aware of that

 

[agybag]

Hello the best way to prove the energy production is to use optimisers or a system to measure ac and Dc production. You also have to check if the panels are genuine. I had cases where peopled have been cheated with fake labels....be aware of that

Thanks for the info

 

[agybag]

Thanks for the info

Update, had the installer call in a few days ago and he advised me there was a fault with the inverter. A replacement has been ordered and should be fitted soon

 

[JimmyTheJock]

Update, had the installer call in a few days ago and he advised me there was a fault with the inverter. A replacement has been ordered and should be fitted soon

Just wondering if you have had any luck getting this sorted?

It's about 5 weeks since you told us the supplier was sourcing a replacement inverter and I hope by now they have got the system up and running properly.

We've had some nice cool sunny days recently so peak output ought to have been around the maximum you can reasonably expect.