Larger 6kWp+ domestic install before the FIT cut

[BruceB]

Rushng out now, but at first sight i do not see that limiting output of a SE 4000/5000/6000 would affect the maximum on the input. The right person on the phone or email at SE could clarify.

Yes it is me over there.

 

[wtc]

Following up my original post, I did get a system installed in December on the old FITs, but not in excess of 6kWp though! It comprises 20x 250w panels to give 5kWp fed into a SolarEdge SE4000-16A inverter, so done under G83/2. This is within the warranty limits of the SE4000-16A.

It was a different installer to those who had given quotes around the time of my original post and a firm who inspired more confidence at the quote stage but I have also been happy with the end result.

There just didn’t seem enough time to get a G59 application in, and looking back now, the chance of it getting approved installed by mid-January would have been tight. As it is, under G83/2, it was installed before the rate cut.

The 20 panels have been installed on a single string. No need for four!

During December and January there was significant shading from trees. It was only into mid-February that the whole array has been getting into full sun. However, Tuesday it performed very well. It was only just clipping around midday, at just a fraction over 4kW according to the SolarEdge monitoring.

A few other observations from the quote process:
- No-one mentioned voltage optimisation, which I’m happy about.

- There was a fair bit of misleading in terms of self-consumption around the quote stage. My chosen installer was the most honest saying it may only be a third. I did have quotes allowing for 75% and 90% self-consumption. While these two did include iBoosts making a higher proportion possible, this was put into the financial projection as imported electricity saving to over-inflate the payback. A bit of a wheeze to make costly systems seem better value. Including the 7.7kWp system forecast to produce 7171kWh per year with self-consumption at 5487kWh, even though our household only uses around 4000kWh per year.

- There were different attitudes to the tree shading, ranging from stating there is no issue to carrying out detailed measurements and putting them into PVSOL (though I would only get the full results if I went ahead). But it made very little difference to the proposed panel layout between different quotes.

- My installer was happy to either connect to a spare way in the existing CU or put in a 2-way CU and I asked for the latter. Others seemed to be reluctant to offer the small CU when I had a spare way.

Going back to my original brief, I was hoping to benefit from economies of scale with the bigger system, since there was still only one inverter, one design, one set of scaffold etc. What I seemed to find was that there were competitive prices around the 4kWp mark, but going above this would cut the firms willing to quote and bring in G59 costs, so not necessarily giving a better return.

Thanks to those who posted.

 

[Worcester]

@wtc Thanks for posting back, it's always good to hear the final result.