Solar panel production figures

Panel life.

Like most of you I tried to choose my panels carefully.

Back in October 2011, I paid just over £2k extra for a 4kw system with Sanyo (now rebranded panasonic) panels.

They knocked spots off the opposition, and set a standard everyone else had to catch up with.

Scroll forward 10 years and I installed another 10.4kw in September 2021. For many years I used to get quite a lot of 26 and 27kw out of my Sanyo's, the best being 27.9kw in a day.

Over the last year or so I have noticed that we are not doing so well. I knew roughly how much my out put from them would be once I had downloaded the data for the new panels (this is 4.8kw on my eastern roof and 5.6kw on the southern one). My guesstimates became less accurate.

Last June we had our best month ever. Days that are close to being perfect in solar terms get highlighted in my spreadsheet. We had 16 last June. Previous best was May 2020 when we had 12. Some months have none. Anyway last June we did not get even one output of 26kw.

With no hard evidence to support me, I think the performance of my Sanyo's has dropped my by some 8-10% in the last 2 years. I do remember that he original spec showed performance dropping off over time. I am reasonably certain that we are looking at a problem in the age of the panels and nothing else. Since installation the Sanyo's have produced over 54,750kw, so we have done much better than I ever thought we would
 
…and out of nowhere comes a record day. 63.6kwh, exported 56kwh.

Still not perfect as you can see but it’s the most the system has outputted for some time.

ITtUpZS.jpeg



The next best day was 59.5 on 19/5!
 
Peteronthesouthcoast said:
Back in October 2011, I paid just over £2k extra for a 4kw system with Sanyo (now rebranded panasonic) panels.
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That must be a very early FITS system, and even though very good quality panels, I suspect the efficiency was very low to start with. Have you considered replacing the panels and inverter with a modern system? FITS payments would be pro-rata'd based on system size increase, but I bet with panel improvements you'd get a big uplift in generation and thus payments, as efficiency increases aren't accounted for. Today's panels also work better when cloudy.
 
Ron-ski said:
That must be a very early FITS system, and even though very good quality panels, I suspect the efficiency was very low to start with. Have you considered replacing the panels and inverter with a modern system? FITS payments would be pro-rata'd based on system size increase, but I bet with panel improvements you'd get a big uplift in generation and thus payments, as efficiency increases aren't accounted for. Today's panels also work better when cloudy.
Click to expand...

I'm in a similar situation. The generation appears strong but if I changed i'd still be capped at 3kw on the inverter as my g99 limited me to 14kw (5kw battery, 6kw new inverter, 3kw old inverter) total with an export of 7kw. As long as thr old system does not die I think i'll just let it keep running for the duration of the FIT. Extra financial investment would be better spent on moe panels and over loading the new inverter.
 
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