Our solar PV array production

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Home Farm

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Our solar 6kW PV array has been up for four months and I thought it was a good time to have a look at their performance providing an unbiased report, based on real life experiences, illustrating power output on overcast, rainy and sunny days in the UK.

You can watch the video here: https://youtu.be/wsyPOzZkKNY

More information on our array is available here: https://myhomefarm.co.uk/solar-pv-and-inverter-review

Would be very interested to hear comments and how our array compares to yours.

 
interesting video. JA 280W panels are bit low spec these days but a good panel none the less. As for the inverter, I'm not a fan of Solaredge where you don't have shading issues, it costs more than 1-2% higher output is worth on non-shaded roofs. I will now try to explain the inverter under sizing.

8 years ago, when I first started installing solar systems, many inverters were still transformer types. The efficiency of these could drop to as low as 70%, so to compromise for loss of performance in lower light level weather conditions, it was advised on all the training courses, to under-size the inverter by up to 20%. You lose some of the perfect weather performance but gain at all other times to give a higher annual yireld. However, since then inverters have improved an awful lot, and the current Transformerless designs maintain efficiencies as high as around 94%. This makes the advice previously given a non-sense, but most companies still do it, because smaller inverters are cheaper, and I don't think anyone has changed the training courses? I now prefer to size inverters on a like for like basis, ie 6 kW for 6 Kw of panels, or perhaps slightly larger, say a 6kW inverter on a 5.8kW set of panels. The panels are +ve tolerance, so in reality they can output up to 3% more than expected anyway, and I've also found Japanese panels will go higher than the max tolerance stated. Panel outputs are interesting, German do exactly what they say they will, Chinese do what they should, just, Japanese outperform the stated figures. It's a cultural thing, the **** would rather you be happy with a better than expected output so slightly understate the performance. 

 
Good post binky
thank you Roys. I have designed and installed just under 1,000,000 Kw of solar panels systems  which is around 40,000 panels in tiotal - I still wouldn't call myself an expert, but in the early days I used to contact customers on a regular basis to see how their systems peformed against forecast outputs. This has taught me a lot! Having an engineering background, I've also spent a lot of time breaking through the sales pitch BS, which is why I'm not agreat fan of Solaredge. It's a good inverter, but I don't like fitting optimisers behind every panel. The most common failure of a solar system is damp in the connectors and the SE system doubles the amount of connectors on the roof, It also means you have fitted a gadget that will fail at least 10 years before the panels, so will require a major rework of the roof intallation. My main beef with SE is the sales reps talking lettuced along the lines of it will generate 30% more than a standard inverter. The test referred to was comparing against a grade B inverter, I only fit grade A, and its true it will output 30 % more with serious shading issues against a grade B unit. However you can fit an SMA with shade compensation and get the same result for a lot less money, and if you had shade issues like that, it's debatable if you should have panels fitted in the frst place. On the upside, it is a safer system when shut down and works slightly better of you get a lot of leaves or bird poo on the panels.

 
Well spotted Tony, looks to me like two 00’s too many for. 40,000 panels, which fair play to binky, is a serious amount of panels😀

 
it certainly is, panels fitted vary from 180W to the newer 330W we have fitted over the years, so there is a typo 4,000 panels or there abouts. I used to have 5 staff, biggest job we fitted was 100 kW, something like 400 panels in it's own right. We did a few large school jobs, whic is what bumps uo the numbers. Anyway, my carbon footprint is well covered!  :^O

 
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