Adding in more panels at a later date.

MicraShed · Aug 20, 2012

Thoughts gentlemen please:

My roof faces nominally SE and has 10x250w panels where the yellow dot is ^^^

The opposing roof faces NW, yet gets direct unshaded sun from about 3pm to 7pm during summer months, less in winter obviously.

Now, the original plan was to add in another 5 or 6 x 250w panels on the extension roof (also SE facing) but I have been increasingly thinking about 5x 250w panels on the NW roof to even out energy production.

I know traditionally North facing installs are frowned upon, but looking at how much light the front roof gets and for the time it gets it for leads me to think it would be for me a better bet than adding to the other SE facing roof.

Im also wondering if i could get away with keeping the existing Fronius IG 30 inverter as the peak power shouldn't go above the units threshold.

So, thoughts if you would be so kind....

SolarCity · Aug 21, 2012

I can't work out where your extension roof is on your picture but I would you would be better off installing on that instead. NW roofs can be worthwhile but you will definitely need a new inverter.

MicraShed · Aug 21, 2012

Its not a great picture is it?
The extension is the lighter grey roof below the yellow dot (main roof).

This diagram illustrates it a little better - my house is a semi, there is a single storey extension to the rear, but the roof to this attracts shading partly from two large trees on neighbouring property that dont affect the main roof (though they will impact in winter when the sun is lower).

Though the front half of my roof is NW facing this has full and uninterrupted sunlight from when the sun is round that side, usually from about 2 to 3pm onwards. The front has no shading issues.

The reason Im thinking this way is more to do with continued generation during the day, I see a real drop off in power generated from about 3pm with the panels where they are, but if I could boost that generation to later in the day then I would have more usable electricity for the house.

For me the idea of PV has never been about the FIT - the FIT merely enables an earlier repayment time for the initial outlay. Given the falling install costs of PV it can only be a matter of time before the FIT becomes far less relevant to most people anyway ( compare my install at a little over £5K with my friends install 18 months earlier at a little under £11K for almost the same output - he is on the 40-odd pence FIT, I on the 20-odd pence FIT).

I mean thats only my thinking as a layman and bog standard consumer. I have only had my system up and running 4 weeks, however I have dramatically managed to cut my import from the grid by my own generation and thinking a bit more about how I use the electricity we generate and we need to import, Im also lucky in that the house is occupied during the day so we can use the power generated.