Solar generation for last qtr

[flyonthewall]

We have two 3.6kw systems for 97 days (22 July - 27 October) we generated 520kw on one system and 502kw on the other. This seems pretty low to me at around 5kw a day. Panels are S.E at 12.5 degree and were thoroughly cleaned by me before the period. Does it seem low, or has it been that cloudier late summer?

 

[akaPABLO01]

We have two 3.6kw systems for 97 days (22 July - 27 October) we generated 520kw on one system and 502kw on the other. This seems pretty low to me at around 5kw a day. Panels are S.E at 12.5 degree and were thoroughly cleaned by me before the period. Does it seem low, or has it been that cloudier late summer?

Let’s say you are in the Northwest of England.
I would expect 781 hours of sun, se @ 12 degrees

4% July
13% August
9% September
5% October

781x5= 3,905kWh annual

4+13+9+5= 31% of annual turnover

3905x0.31= 1210.55kWh within this period for 5kW

Looks like you are 50%+ out!

I could be wrong but I highly doubt it unless your off the coast of North Scotland.

I am wrong, use the formula for 3.6kW!!!

871kW over the period

Not sure where I got 5kW each but you are still out.

 

[upnortheast]

Just sent our quarterly read in
30kw at 55 degrees north
28th July - 27 Oct - 7467kw
So you have total of 7.2kw panels
So our 7467 / 30 x 7.2 = 1792kw
So yes yours seems off the pace you don`t say where you are,
Seems the weather in Eastern England has been a lot better than North west England or Western Scotland.
Friend near Kendal says he has had rain 95 out of 115 days, not good for solar

 

[akaPABLO01]

Yup
Figures on my sites showed a poor summer especially June

This year has been a wet one

 

[flyonthewall]

I'm on he south coast near the isle of wight. Before I cleaned the panels I was peaking at 2.8kw, since cleaning they have been up to the inverters maximum of 3.6kwh and some days have seen 22kwh per system, so over 40kwh in total. Average in Aug was nearer 14 kwh/day, so I am perplexed why the readings are so low. Perhaps the panels aren't performing as they should?

 

[akaPABLO01]

I'm on he south coast near the isle of wight. Before I cleaned the panels I was peaking at 2.8kw, since cleaning they have been up to the inverters maximum of 3.6kwh and some days have seen 22kwh per system, so over 40kwh in total. Average in Aug was nearer 14 kwh/day, so I am perplexed why the readings are so low. Perhaps the panels aren't performing as they should?

It’s hard to suggest there would be an issue but that far south should see more generation over the period then I suggested you should yield using figures some 200 miles further north.

How many stings are at the base of the inverter I would expect maybe 2, which will see 4 cables entering the base of the inverter from the roof.

Do you have any shading?

Do you suffer power cuts?

How long have you had the install?

Are the panels in one continuous block or dotted around dormas? Maybe take a picture and post it?

How many panels per install?

If you look at your mcs certificate you’ll see the model number, put this in your reply.

What inverter model number are they?

Seems a tad strange that both are reporting the same huge losses which brings me back to power supply?

 

[f0ster]

you might also measure the grid voltage, if it is going over 253vac the inverter will keep restarting every few mins.

 

[flyonthewall]

There are 16 panels per system (Azur 235-1 2p 235w ea) total 3.76kw. Inverters are Aurora Power one, with a capacity of 3.68 kw. Annual production forecast to be 2 x 3685kw.

Installed 18 July 2012. Meter readings 27 Oct 2017: 16770 and 15712. Days since install 1927: avg: 8.702 kw/day; 8.1536 kw/day. Annual production: 8.702*365 = 3176 kw; 8.1536 * 365 = 2976 kw.

Known problems: panels installed at 12.5 degree rather than 25 degrees as per sap. Compass bearing is 155 degrees. The system with the lower figure due to rcd tripping and electrician attended resolved.

Panels were very dirty with moss etc, so were steam start of July 2017. Peak daily through July was over 20kw. No known shade, no tripping or obvious problems.

Will take photo tomorrow!

 

[akaPABLO01]

There are 16 panels per system (Azur 235-1 2p 235w ea) total 3.76kw. Inverters are Aurora Power one, with a capacity of 3.68 kw. Annual production forecast to be 2 x 3685kw.

Installed 18 July 2012. Meter readings 27 Oct 2017: 16770 and 15712. Days since install 1927: avg: 8.702 kw/day; 8.1536 kw/day. Annual production: 8.702*365 = 3176 kw; 8.1536 * 365 = 2976 kw.

Known problems: panels installed at 12.5 degree rather than 25 degrees as per sap. Compass bearing is 155 degrees. The system with the lower figure due to rcd tripping and electrician attended resolved.

Panels were very dirty with moss etc, so were steam start of July 2017. Peak daily through July was over 20kw. No known shade, no tripping or obvious problems.

Will take photo tomorrow!

Have you kept records of quarterly figure submission?

I’m away working in Bradford this week and back in the office Monday. I’ll do a monthly expected yield prediction using the data you’ve provided.

Do the sites have full mains metered connection or prepaid meters?

And it’s the isle of white for reference so I can pull solar hours?

If you get chance pictures of the inverter base showing cables enter and full internal picture. Tar

 

[flyonthewall]

Thanks, buying in elec is getting dear jumping form 10p/ kw to 11.7p/kw hence every bit saved is good. I expect the panels are lossing efficiency, perhaps plumb a few more in?!

 

[akaPABLO01]

Thanks, buying in elec is getting dear jumping form 10p/ kw to 11.7p/kw hence every bit saved is good. I expect the panels are lossing efficiency, perhaps plumb a few more in?!

So the inverters are rated at 3.6kW, what number of solar panels are on the roof and at what rating is each one?

You’ll get the model of the solar panel from your mcs certificate or in your handover pack.

 

[Exfarmer]

Thanks, buying in elec is getting dear jumping form 10p/ kw to 11.7p/kw hence every bit saved is good. I expect the panels are lossing efficiency, perhaps plumb a few more in?!

Nice idea, but it is fraud

 

[f0ster]

as long as the inverter is locked to 16 A max you are complying with the regs, most people install 4kw but even that is more than it should be, 3.65kw is the required amount.

 

[akaPABLO01]

as long as the inverter is locked to 16 A max you are complying with the regs, most people install 4kw but even that is more than it should be, 3.65kw is the required amount.

People only installed 4kw because of the tariff. You can install upto 10.

The difference is whether the install falls under g83 or g59 regulation.

That’s 16a @ 3.68kW for g83

Class of g59 is above 17kw and must have relay, so in theory you could probably apply 16kW on single phase.

 

[akaPABLO01]

ok, @flyonthewall

16x 235= 3.76kW

solar hours annually, 938

3.76x938= 3,526.8kWh

Jan - 3% - 105.8kW
Feb - 4% - 141.07kW
Mar - 7% - 246.87kW
Apr - 11% - 387.94kW
May - 14% - 493.75kW
Jun - 15% - 529kW
Jul - 14% - 493.75kW
Aug - 13% - 458.48kW
Sep - 9% - 317.41
Oct - 5% - 176.34kW
Nov - 3% - 105.8kW
Dec - 2% - 70.53kW

100% @ 3,526.7kWh

22 July - 27 Oct = 143.34, 458.48, 317.41, 153.58

each systems optimal performance should yield 1,072.81kW during this period with a 10% over/under performance.

Your system is 50% performance and the strings entering the inverter(s) need to be tested.

 

[flyonthewall]

Yeap thanks for the update, the last read should have been a month earlier so the actual figure is not accurate. One system had a low riso and didn't fire up Sunday, so has water entering somewhere so some maintenance is needed - perhaps its a panel or if lucky just a a dodgy joint. The panels are not at their optimum angle (12.5 degree and orientated 155 degrees). From what I recall the panels are wired in series, so I suppose if one panel is dodgy it will bring down the performance of the others. I presume when you refer to "strings" these are the number of sets of panels wired like this? (sorry I am but a thick farmer, I do like to try to understand.....)

 

[royboy1964]

Nearly averaged 4000kwh a year (Clacton area)from a 3.82kw over a six year period would have been over 4000 if wasn’t for the inverter (Aurora power one) packing up in summer 2016

 

[flyonthewall]

You must be due south and have panels at the perfect angle? I should add my system was working again Monday, so need to find the leak!

 

[akaPABLO01]

You must be due south and have panels at the perfect angle? I should add my system was working again Monday, so need to find the leak!

Yeah, string will be a series of 8 panels and 2 strings on each system I assume. So 4 cables entering the base of the inverter from rooftop.

That solar hour calculation I did is at your pitch and south east angle, so it’s what you should be achieving.

I expect you may have a blown mc4 on both systems on one string. You have 4 external mc4. 2 on the positive and 2 on the negative cables connecting the series of panel.

Switch everything off. Remove a string and start up the inverter then switch off and plug back in and remove the other string and switch on < that’s the untrained way of testing whether a string is faulty having no dc test kit.

Solar panels usually have what’s called bypass diodes. If a panel doesn’t complete its circuit run then the current bypasses though and continues on. Only when there is an mc4 fault does it cease circuit.

Test out on a sunny day, lunchtime.

 

[warksfarmer]

It’s been normal here 163.38kwh per day off a 70kw system now just over 6 years old.