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Are extra panels always worth it?

  • 30-10-2024 07:31PM
    #1
    Registered Users, Registered Users 2 Posts: 856 ✭✭✭


    Evaluating an E/W installation, 16 versus 20 panels (+1100 EUR). ROI is likely to be the same, with less risk due to lower reliance on the FIT, so I'm not sure I see the point in shelling out the extra on the additional panels. Thoughts?

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Comments

  • Registered Users, Registered Users 2 Posts: 1,849 ✭✭✭Deagol


    The extra panels will come into their own in the 5 months between mid-October and mid-March and will make a difference on cloudy days other times. Always put up as many panels as you can fit = the panels are cheap compared to the cost of getting someone out to fit them!



  • Registered Users, Registered Users 2 Posts: 1,031 ✭✭✭cobham


    Max out on panels as cant add in later so easily…



  • Registered Users, Registered Users 2 Posts: 1,592 ✭✭✭DC999


    I've E and NW. NW hibernate from end Sept to Paddy's Day. Sun just doesn't hit them. They are still great for the other 6 months. So it's worth checking how 'E' you are

    +1 on max what you can on Day1. Output drops loads from late Sept to Paddy's Day. More panels = bigger engine all the time



  • Registered Users, Registered Users 2 Posts: 2,700 ✭✭✭bullit_dodger


    I know it's always a juggling act, but this is one time where you should get as many as you can fit. If you can get more than 20 such as 22 on there….do it. It'll reduce your payback time.

    +1 on what everyone says. I've an E/W myself. originally got 5.3Kwp as that was all I could get onto the roof and get the grant, then once I recieved the grant got 3x extra panels by reconfiguring the panels on the roof (I couldn't get them originally as it was smaller than the regulations for SEAI to give the grant).

    In summer I can be generating 700-800 units and getting paid for it, in winter in contrast, if I break 80kwhr in december I'm doing lucky. Sadly it's in winter you need the power the most.



  • Registered Users, Registered Users 2 Posts: 791 ✭✭✭conor_mc


    it’s relatively easy to add battery capacity to de-risk FiT changes in the future, much harder to add panels to capitalise on changes. Looking at UK market, we’re likely to eventually get tighter time-of-use bands with more extreme prices/FiT, so as others say, max out the panels as they won’t get much cheaper than they are right now to buy and they’ll never be cheaper to fit. Haggle hard though!



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  • Registered Users, Registered Users 2 Posts: 856 ✭✭✭spuddy


    The only spot we would have for a battery is in the attic, and I don't like the idea of having one up there. Upgrading to a hybrid inverter is the roughly the cost of 3 panels, which will have an immediate ROI, so I'm inclined to stick with the string inverter.



  • Moderators, Sports Moderators Posts: 18,289 Mod ✭✭✭✭slave1


    More the merrier but be sure to do the math on N facing as you'll get nothing worth talking about in shaded N facing panels for 4-5months of the year, in the best months the N panels may contribute to clipping which is also a waste

    My stuff on Adverts, mostly Tesla Pre Highland Model 3

    Public Profile active ads for slave1



  • Registered Users, Registered Users 2 Posts: 177 ✭✭paddyman


    Hi all, I have had a system priced for 12kw but I can potentially fit 18kw if I absolutely maxed out East, South and West roof space on the Bungalow.

    How far would you push the "max out the number of panels" idea?. Since its across 3 x aspects the 6kw export limit should be OK (perhaps some clipping in summer). Is 18kw just too much to consider?.

    I dont mind the initial extra cost if payback over time covers it.



  • Registered Users, Registered Users 2 Posts: 623 ✭✭✭idc


    There is no 6kW export limit. The limit is the size of all your inverters for NC6. And the limit is 25A approx 5.75kW.
    Don't know of any 5.75kW inverters hence most people end up with a 5kW one.
    Thus the number/size of panels will purely be down to the inverter you pick. Most now do 200% oversizing ie 5kW inverter allows for 10kW or panels.



  • Registered Users, Registered Users 2 Posts: 2,700 ✭✭✭bullit_dodger


    Yeah, a max of 10Kwp in panels is usually in about the most that 95% of us will see - the other 5% being folks who go NC7 route along with multiple inverters/three phase which is outside the realms of most domestic users.

    There's also the string voltage to consider on an inverter. That's usually in about 600v per string, but the string voltage is somewhat dependant on the specific panels you have. Different panels have different Voc (open circuit voltage)

    Most panels are in about 40-45v each, but I've see some on here in the 30's and even some with 50v+ per panel. So you might find yourself limited to 12 or 13 panels on a specific string. 12 panels seems to be about the norm as you might not want to go very close to the 600v limit for reasons I won't go into.

    So 12x400w panels = 4.8Kwp and then two strings will put you at 9.6kwp. That's a pretty decent setup.



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