How much did your 3.6kW system make yesterday/today?

[stuart99]

This link below gives a realtime output of my PV system (covers the last 3 hours).

So far today, I'm produced 14.62kWh on a Sharp 14x240W system with SMA 3000HF inverter. 249kWh in total for April so far.

https://api.pachube.com/v2/feeds/40789/datastreams/4.png?width=730&height=250&colour=%2324f134&duration=3hours&legend=kW&title=Solar%20PV%20generation%20(Midlands)&stroke_size=2&show_axis_labels=true&detailed_grid=true&scale=manual&min=0&max=3250&timezone=London

 

[Trader9]

stuart99

Can you add your house load onto the graph, so we can see how the two align. It would be interesting to see how much of a match or mismatch there is between the two.

Regards trader9

 

[overland]

We have a 3.68 KW system with Trina panels on a SSE facing 35 degree roof with no shading and a Sunnyboy inverter. Installed in December 2011 the March figure, with the good weather, was exceptional generating 393 KWh. However, this month it only just exceeded what the Energy Trust calculation said it would for April and produced 381KWh. Out of interest the highest output from the system appears to be 3.62KWh and I have noticed that a number of reporters achieve figures in excess of their system's stated maximum output so not sure whether my system is under performing. However, as the system, other than April has always exceeded by at least 15% what it is official supposed to I cant really complain.

Swansea about 1/4 mile from coast

 

[pwboston]

Well i would say your system has done well for April.

My System a 4kw facing South (Lincolnshire) did 407kw in March but 331kw in April due to the exceptional bad weather, looking at it only the 1st and last day were any good. Mine also peaks at 3.62kw constantly as that is the designed system allowed by the DNO, unless permission was give so the inverter will stay with that, so i wouldnt worry too much about it. So my Aptil figure was down by about 50kw but March was up by 117kw.

That said it literally only needs a couple of extra days sunshine and it would have been there, yesterday 30/4/12 my system did 25kw, so you can see how the figures can easily be achieved and i think getting the amount you and I did considering what this month has been like is still very good.

 

[overland]

Well i would say your system has done well for April.

My System a 4kw facing South (Lincolnshire) did 407kw in March but 331kw in April due to the exceptional bad weather, looking at it only the 1st and last day were any good. Mine also peaks at 3.62kw constantly as that is the designed system allowed by the DNO, unless permission was give so the inverter will stay with that, so i wouldnt worry too much about it. So my Aptil figure was down by about 50kw but March was up by 117kw.

That said it literally only needs a couple of extra days sunshine and it would have been there, yesterday 30/4/12 my system did 25kw, so you can see how the figures can easily be achieved and i think getting the amount you and I did considering what this month has been like is still very good.

Thanks for the reply. March was amazing! With regard the April figure, as we are close to the coast we do benefit from less cloud than places further in land. This is especially applicable on showery days as the cool sea this time of year reduces the build up of cloud. As to the maximum output I'm sure a read somewhere that you should allow for around a 15% loss based on inefficiencies in the system.

 

[FB.]

Thanks for the reply. March was amazing! With regard the April figure, as we are close to the coast we do benefit from less cloud than places further in land. This is especially applicable on showery days as the cool sea this time of year reduces the build up of cloud. As to the maximum output I'm sure a read somewhere that you should allow for around a 15% loss based on inefficiencies in the system.

The maximum output from the panels may well be 10-15% reduced by inefficiencies in the system, but your generation targets provided by your installer should already take that into account.
The actual efficiency depends on the weather conditions.
On a dull day, the cables and inverter may "waste" a large amount of the power flowing through them, but on a bright day, with plenty of power, the losses become minor and the whole system will have less than 10% losses, perhaps as little as 7% losses.

But I've found that on really bright days, the solar panels themselves can exceed their nominal rating - for example, my 250W panels can be generating as much as 270W each (i.e. my 3.75kWp array can sometimes deliver 4.0kW of power to the inverter, which, although capped at 15.65Amps, has also been outputting above its nominal 3.6kW capacity; often approaching 3.8kW in particularly bright sun; 15Amps x 250Volts local grid voltage = 3.75kW).