4kw system?.

Spats

Hi. 
System is

Ja 330w black panels x 12
Growatt 3.6kw inverter
Solo 2 monitor. 

Just had a 4kw system fitted last month, with the lovely weather we had I was expected to see on my solo 2 monitor 4kw but that never happened, it was 3.35kw tops.

From Glasgow, South facing roof 30 degree pitched roof, no trees nothing to stop sunlight, daylight. 

What should my output be guys / gals. 

The panels is 3.96kw output also MCS has given the output at 3.17 kw.

What should I achieve please, thanks and sorry for the long story trying to get in as much as possible. 

Heedtheadvice

Just for starters as a guide.

Spec max output is for absolute best conditions. I find that this time of year is not the absolute best usually hat is in May.

Several reasons why you mightnot be getting max.

Panels are not perpendicular to the sunlight e.g. at 1p.m. approx the sun is at about 47degrees (not 60, i.e. 90 degrees minus your 30) and nearly due south. Both angles need to be perpendicular for max energy collection.

Could be that the sky above you is not as clear as it could be.

Panel efficiency drops off with higher temperatures

Inverter is not 100% efficient.

Some dirt on panels....

etc.

I have a similar system (overall peak output) and recently been maxing at about 3.2kW and only once over the last month close to 4 for just 10 mins early p.m.

You should under normal weather circumstances reach the calculation done for you by the supplier -a standard calc that is used for comparison purposes - over the whole year.

Edit: I am about 75 miles further South so reasonably comparable.

Spats

Thanks bud, 
I am due South
Get sun from 7am to 7pm East to West. Sun is on top at midday

My max output was always 3.35kw never above. 

Supplier never told me that I would never get 4kw at anytime, not very pleased to say the least. 

Cheers 

EVandPV

Also, your output will be limited by the spec of the inverter so as yours is rated 3.6kw, you won't see much above that even at the best of times.
Maybe short bursts just above 3.6kw when the sun suddenly appears from behind clouds but I doubt it'll ever hit 4kw.

Spats

EVandPV said:

Also, your output will be limited by the spec of the inverter so as yours is rated 3.6kw, you won't see much above that even at the best of times.
Maybe short bursts just above 3.6kw when the sun suddenly appears from behind clouds but I doubt it'll ever hit 4kw.

So your saying that I should've had a 4.2kw inverter fitted, rather than a 3.6kw.

The heisscheme says that I should have 3.68kw maximum output, so the installer has the correct inverter installed.

But I payed for a 4kw system and that I would have to take them to court.... Nightmare

EVandPV

No, it's normal to have the inverter rated lower than the total output of the panels.
That's how most installs are done so your inverter sounds fine with a 4kw array of panels.
Ours panels total 3kw but the inverter is rated 2.7kw max.
We rarely see 2.7kw and usually it's around 2.5-2.6kw on a perfect day.

Spats

EVandPV said:

No, it's normal to have the inverter rated lower than the total output of the panels.
That's how most installs are done so your inverter sounds fine with a 4kw array of panels.
Ours panels total 3kw but the inverter is rated 2.7kw max.
We rarely see 2.7kw and usually it's around 2.5-2.6kw on a perfect day.

Thanks bud, 
I just don't understand why it's sold as a 4kw system but classed as over 3kw, so I would never see 4kw anyway.

Really annoyed about it. 

Cheers bud. 

EVandPV

Just the way it is mate. Our system is classed as 3kw but we'll never actually get 3kw. That was the max number of panels we could get on our roof back then anyway.

I think if you wanted to see 4kw of leccy going through your generation meter, you'd need a 4.5kw or maybe even 5kw system.

Spats

Thanks fella for giving me an insight in how it works. 

Going to cost mate to up the panels and inverter etc.

So will leave as is.

Thanks again for your advice. 

Reed_Richards

Spats said:

So your saying that I should've had a 4.2kw inverter fitted, rather than a 3.6kw.

The heisscheme says that I should have 3.68kw maximum output, so the installer has the correct inverter installed.

But I payed for a 4kw system and that I would have to take them to court.... Nightmare

The reason you have a 3.68 kW inverter is because you are not allowed to export more than 3.68 kW without being granted special permission and the easiest/cheapest way to achieve that is by limiting the output of your inverter

arty688

Also in the scheme of things over the year the number of times your panels would go above 3.6kw would be tiny if any given your location and the electric generation you are worrying about would be pence. To be fair though this should have been explained to you.