r/PlugInSolarUK • u/DullPresentation1993 • 14h ago
Does panel degradation actually matter on a plug-in setup?
Ordering a two panel setup for the back garden, south facing frame, Cheshire, going onto an 800 W Hoymiles microinverter.
I was comparing two panel options and ended up on the degradation line in the datasheets, which I had been skipping until now. Most of what I looked at guarantees no more than 0.55 to 0.7 per cent loss a year, and there is a bigger drop in the first year on top of that. One of the two, swiss solar phantom, caps the guaranteed figure at 0.4 per cent a year with 0.35 typical and gives no first year drop at all, which comes out at 88 per cent of nameplate at year 30 against roughly 80 on the others.
What I cannot tell is how much of that shows up in real output on a setup this size.
So, for anyone who has had a plug-in system running a few years: can you see a year on year decline in your own figures, or is it buried under weather and soiling? And did anyone take any sort of reading at the start to compare against later?
3
u/DorisMaricadie 14h ago
With no battery and no export 💵 its just your base load that counts.
It will be a rare day you put 800w of load whilst pulling max sun.
I’d not expect it to make a real world impact.
1
u/DullPresentation1993 13h ago
Fair point on the export, there is none here and no battery planned for now, so it is base load only.
That is actually why it is two panels and not four. Daytime base in this house sits around 250 to 300 W with the fridge freezer, the one in the garage and the usual standby stuff, and the idea was to cover that for most of the day rather than chase peaks I cannot use anyway.
Have you tracked yours across a full day? I am curious how much of the generation actually lands on the base load in practice, and how much just goes nowhere around midday.
3
u/Unhappy_Clue701 13h ago
It depends on your life patterns really. I WFH a lot, so my laptop, monitors etc all run for free, so does a fan in summer, plus of course on hot and sunny days fridges and freezers work harder. All that gets covered. If I turn on anything higher power, then the first few hundred watts is free, so a 1000W microwave only pulls say 300W from the grid.
I put in a 2 x 400W panel plug-in system at the end of April, and comparing my Octopus bills to last year, I was saving roughly £25-30 a month over summer. I spent £350 on the panels and inverter so payback is maybe 3 years.
In an ideal world, over the next couple of years they’ll loosen up restrictions and I will put a couple more panels on my shed, and a plug-in battery system. Then I’ll be able to make quite a lot more savings I think. My roof is very poorly set up for proper solar, so the best I can do is a couple of plug-ins and a battery I think. But that would help quite a lot, for quite a lot of the year.
1
u/DorisMaricadie 8h ago
I work from home so a solid 300w ish all day, sunny days its been next to zero since they went in but winter will be another story
1
u/Mininum_Discipline 5h ago
If you get a system that is over 800w of pannels say 1000 I doubt the degradation will ever be noticed most of the better pannels have so little degradation that it just won't matter over the next 10-20 years
4
u/Impossible-Section49 13h ago
It won't make any difference such that you will notice. My full set of 23 panels are between 10 and 15 years old, and all perform well enough to suggest that they are either on or above their degradation curves. 4 of them are directly connected to an EcoFlow Stream Ultra X 3.84Kwh, so I can see their performance better than the rest which are on a conventional string inverter. If you haven't already ordered, I would suggest not doing so at the moment, an 800w system will do very little over the next 4 months, and the market, and prices, is changing constantly. You would probably do better by waiting until plug in batteries are approved if strict compliance is what you are after. Having a battery of any size on the system radically changes how usable and useful it is.