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Solar PV Panel comparisons

  • 23-11-2021 8:52pm
    Registered Users Posts: 97 ✭✭ Tuttlinghorn

    Hi folks

    if this is duplicated elsewhere pls let me know

    I am comparing quotes and installers, getting recommendations etc.

    I am also trying to compare the various panels that seem to be popular in the Irish market (QCells, Longi, JA Solar, Peimar ... others ?)

    I am looking at efficiency ratings as a main comparison point, then the linear performance warranty, product warranty.. vs cost.

    I am wondering what other important specs to watch for and how to compare them e.g. to indicate performance in low light / typical grey Irish day?

    Below is a listing that I found on a UK based solar comparison website, with a couple of items removed which didn't seem that relevant. (power, weight, size - though i guess it depends on whether the buyer is constrained by roof type/size vs quantity and weight of panels)

    or even better = anyone already made a comparison chart showing the more popular models in the irish market ? !

    1. Efficiency: Solar panel efficiency, which is expressed as a percentage, measures how much sunlight can be converted into usable electricity. Most domestic solar panels have an efficiency of 15-20%.
    2. Power tolerance: This factor determines how much your system can deviate from its stated power (watts). This deviation can be expressed either in percentages or watts. If a 100W panel has a power tolerance of +3% / −0%, then the actual power may vary between 100-103W. If the power tolerance is +5W / −0W, then the actual output varies between 100W and 105W under real-world conditions.
    3. Temperature coefficient: You want to know how much your panel’s efficiency will be affected by temperature rise. Temperature coefficient expresses the percentage decrease in power output per 1°C increase in temperature (after 25°C).
    4. Product warranty: Solar panel manufacturers offer warranties on their equipment, ensuring they can last. Warranties on our list range from 10-25 years.
    5. Performance degradation: Every solar panel will experience some kind of performance degradation over its 25-year lifespan. After the 1st year, there is usually a 2-3% decline in efficiency, and 0.2-0.7% every year after that.
    6. Maximum wind load: You want your solar panels to withstand any kind of weather in the UK, including strong winds and hurricanes. This tolerance is tested by manufacturers and is expressed in pascals (Pa). The higher the number, the higher the wind tolerance, but most panels are certified to withstand 2,400 Pa, which is equivalent to 140 mph.

    Post edited by Tuttlinghorn on


  • Registered Users Posts: 4,753 ✭✭✭ SouthWesterly

    You need to look at the cost Per KW after all that's done and see if the bigger better panels are worth the extra cost

  • Registered Users Posts: 1,619 ✭✭✭ Deagol

    They're ~150euro each - the cheapest part of the whole install / system. Having a 20 year warranty vs a 25 year warranty - do you really think you'll be able to prove in 20 years time when you bought them and be able to contact the supplier even if they still are in business etc? For the relatively small money involved, I would recommend not to worry about it and save yourself the headaches of comparing things. All the panels are very similar - and all you can work off are the manufacturer's claims - and do you really trust them? I went on what my supplier was happy to supply - it'll be him that has to handle the warranty claims in the short term so a decent installer will be unlikely to sell you pure junk.

    If you look at the main / long threads on PV, you won't find anyone who's made specific complaints against any manufacturer for poor performance or failures. Good luck with it!

  • Registered Users Posts: 97 ✭✭ Tuttlinghorn

    installers have been quoting me 250 per extra panel. not the 150 you mention but with some labour and VAT, is that 250 justified ?

  • Registered Users Posts: 1,619 ✭✭✭ Deagol

    my Price is retail material only. I’d say with Labour and mounting materials etc, €250 per isn’t bad. Always haggle though, good margins being made so they have wiggle room!

  • Registered Users Posts: 1,639 ✭✭✭ bullit_dodger

    Depends on the panel, but 150-200 is about the average. Eg.

    Midsummer Renewables

    Course your price of 250 does (probably) include the install? So it's probably fair 250 euros. They have to get a guy up a roof and they have to make a few quid too. Anymore than 250....then it starts to get unfairly pricey

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  • Moderators, Sports Moderators Posts: 16,467 Mod ✭✭✭✭ slave1

    This is reasonable, some installers have a fixed rate per panel, make sense to standardise pricing