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How to compare PV Panels?

  • 25-10-2021 10:46pm
    Registered Users Posts: 97 ✭✭ Tuttlinghorn

    What specs should I look for apart from price and warranty?

    the installer for a friend had told them to avoid Chinese manufacturers, in favour of European ones. Not totally clear why .:.

    thanks for any ideas to help me in my search for a new PV install !


  • Registered Users Posts: 1,636 ✭✭✭ bullit_dodger

    Much to a muchness really with respect to the actual panels. Not sure why you heard that the Chinese are to be avoided. Them and German are about the leaders in the space, but really it's not about the make/model but how many can you fit up on your roof.

    You may (I don't know) find one panel can work 0.5% better, but if it's 10% more expensive is that "better"? Just bang up as many on the roof as you can.....pretty much everyone here will tell you the same.

  • Registered Users Posts: 1,540 ✭✭✭ jkforde

    If you're not technically minded\trained, I would suggest finding a trustworthy installer and trust their choice for your specific needs.. the 'avoid Chinese' reaction is just knee jerk with no basis in fact.

  • Registered Users Posts: 1,270 ✭✭✭ reboot

    There's a wee discussion on small scale PV, to charge our USB devices,led lighting etc,on the Technology thread

    Does not involve feeding into the mains, putting panels on the roof,buying glass panels,or starting out by spending more than €50 .

    It does include,flexible lightweight panels,recycling car batteries, and using 12v dc to 5vdc adaptors costing around €3.

    Depends on your needs, interests, knowledge and ability to dodge the snipers. Good luck,The longest journey,and all that.

  • Registered Users Posts: 843 ✭✭✭ kabakuyu

    Thanks for the info,could you link to the thread, I can't seem to find it.

  • Registered Users Posts: 422 ✭✭ phester28

    I am not an expert but I am an engineer. My installer tried to use a Chinese panel when I paid for amerisolar. Both were rated at 300w peak but if I looked at the 800 irradiance curves there was a much larger drop off on the I V curves. This would mean (at least from datasheets) that the Chinese panels would perform worse on your typical Irish grey days

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  • Registered Users Posts: 1,270 ✭✭✭ reboot

    Sinple,basic and cheapSolar charging of your phone,tablet etc.

  • Registered Users Posts: 97 ✭✭ Tuttlinghorn

    Thank you for this

    Is there an idiots guide anywhere to interpretation of PV specs and meaning of I V curves etc ?

  • Registered Users Posts: 11,100 ✭✭✭✭ Oranage2

    Check on YouTube, lots of easy to understand videos. You can see p-v and i-v curves from the panels manufacturers.

    It's such a big job, not for a diy enthusiast.

  • Registered Users Posts: 1,270 ✭✭✭ reboot

    The simple PV discussion was 0nly for folk who wanted to dip their toe in the sun and learn with a practical project to charge a small lead acid,or lithium battery,which could be used to power and charge devices.

    It isn't to involve installers,PV on the roof,inverters,and feeding into the grid.

    All this information is available on the excellent PV proper thread,which I've stayed away from,where you'll find excellent informed clever people.

    I started down a very cheap and simple road to discover just how far one could go,without involving connection to the mains,in large part driving by regular power outages in this rural area.

    The journey has led to a great deal of the house now running on 12v and 3.7v litium batteries,from breakers yards ,now specialising in Electric Vehicle batteries, the modules of which can be configured to provide various battery packs of differing voltages.

    The local computer shop give me the laptop batteries on their way to the dump,most of the cells are perfectly fine,the electronics shot.

    Battery balancing of lithium has been a big part of keeping the cells working well for long periods,

    So All I'm saying is,not to save money,or compare prices with mains supply, at present,not for long, my Economy 7 supply is very cheap at around 8p/ kwhr,or unit.

    I should declare a disinterest at this point!

    I've no interest in promoting,selling,or making money from anyone.

  • Registered Users Posts: 6,553 ✭✭✭ the_amazing_raisin

    One thing that can separate the premium panels from the cheaper ones is the degredation curve

    For example LG panels seem to degrade much less over their lifetime compared to lower cost panels

    However it can be difficult to justify the extra cost for premium panels

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  • Registered Users Posts: 1,270 ✭✭✭ reboot

  • Registered Users Posts: 5,188 ✭✭✭ zg3409

    One thing to consider is the wattage of the panel versus the size. There is a planning exception size limit some installers ignore, but you also have a roof size limit. If you want most power on your roof, you want panels with high wattage for their size. This is most important if you have a small roof, or shading at times of day due to chimney or trees etc. You may want to not install panels in certain places. Shading on any one panel causes whole string to drop.

  • Moderators, Sports Moderators Posts: 16,460 Mod ✭✭✭✭ slave1

    Optimisers overcome shading, but you need to do the economics of it. My rear NE facing roof gets shading Oct-March from chimney but at that time of the year and with that aspect there would be very low PV being generated so it does not make sense to invest in optimisers.