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Solar panels

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    #32
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    Muhammad CoolS Radium wrote: »
    Any chance you could post up exactly what you have?

    I have 2 arrays of 3 panels each. Both DIY installs on my shed and on my kitchen extension.
    2011 wrote: »
    Do you know anyone in a domestic installation that has installed enough solar panels to charge a car? I certainly don't and I believe that this is due to the cost and size of the array required, which is my central point. Do you agree with me on that?

    Nope. The minimum charge most EVs take is 6A. You will need just a 5 panel array to produce that (that's the token array they stick on new houses these days) on a bright day. It would charge your car up for the 5kWh you need for your average daily mileage in about 4 hours

    Again, obviously not on a dark winters day. But you get my drift. A reasonable array of say 3-4kwp goes a long way to providing for your day time elecricity needs including charging your EV, running dish washer, washing machine, dryer, hoover, lawn mower, etc. for most days of the year. Some people divert the excess to heat water, but I'm no fan of that, as it is very inefficient. I also have a large Kingspan 40 tube solar thermal setup for that as we use a lot of hot water (family of 5 with 4 women :p)


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    #33
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    unkel wrote: »
    Nope. The minimum charge most EVs take is 6A. You will need just a 5 panel array to produce that (that's the token array they stick on new houses these days) on a bright day. It would charge your car up for the 5kWh you need for your average daily mileage in about 4 hours

    Thy sounds like less than the 200 m^2 suggested earlier (which seemed right to me).
    See link:

    https://www.boards.ie/vbulletin/showpost.php?p=108201209&postcount=16


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    #34
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    5 panels is just 8m2 (5 panels * 1.65m * 0.99m)

    6A is needed to charge any EV (6A * 230V = 1.4kW)

    5 panels * 300wp = 1.5kW peak production


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    #35
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    unkel wrote: »
    5 panels is just 8m2 (5 panels * 1.65m * 0.99m)

    6A is needed to charge any EV (6A * 230V = 1.4kW)

    5 panels * 300wp = 1.5kW peak production

    Only 8 m sq. of solar panels and you can charge you EV for free. So apart from servicing the car it will have no running costs.
    It all sounds too good to be true.
    So why isn’t every EV owner doing it?

    With a requirement for 200 m sq. array I could understand the reluctance for such an investment.


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    #36
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    2011 wrote: »
    Only 8 m sq. of solar panels and you can charge you EV for free.

    Obviously only for free if you don't consider the installed costs of the solar panels. The panels themselves are very cheap these days, but installers charge a fortune for the job.

    And as I already stated, you can charge your EV at night rate for about 7c/kWh. I don't want to further bore you with maths, but getting an installer in to setup your solar to mostly charge your EV would have a pay back period of over 20 years.

    If you get the parts at good prices and you do the install yourself, the pay back period is considerably shorter. It would not make sense to install PV just for charging your car though, more for your daytime use of electricity which can not be run out night. There are smart EV chargers that make your house use all the PV electricity first and if there is any left over, it will send it to the car. You get a €600 subsidy when buying an EV charger. And starting this month, you can get a subsidy of up to €3,800 for installing solar PV (install has to be done by an SEAI approved installer though). The subsidy on buying a new EV is currently about €10,000


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    #37
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    2011 wrote: »
    With a requirement for 200 m sq. array I could understand the reluctance for such an investment.

    Its a rough figure calculated at 100Wp/m²
    ( kinda inefficient by modern standards).
    The car I implied would require charge from full depletion of a large 60kWh effective use battery which is not a frequent occurrence.

    Power is power. Cheap power is cheap power. Solar panels are cheap as chips...installation costs more.

    There's zero point trying to charge a car with solar power you can't control what electron does what. This whole idea of a load specific generator is foolhardy. Solar panels offset dinosaur burning turbines and set runtime cost effectively. At a lower environmental and financial price point.

    Lack of uptake of solar in Éire I believe is mostly due to lack of government support for a saleable commodity, lack of education, lack of data on viability and a rather large troupe of charlatans with "free energy & fast payback" schemes.

    The tech works, its cheaper than displacing burning hydrocarbon derived power.

    Wanna talk about reliability?
    I have not had an unscheduled (by me) power cut for over 8 years.


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    #38
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    I read this:
    20kWp would charge most fully depleted car batts on the market ona good day.

    200m² ± array.

    as a 200m² array would be required.
    Are you saying I interrupted incorrectly?


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    #39
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    I think charging a car is a red herring.

    Why is it only the car that is cared about? Its not like the ESB bill differently for cars than other appliances.
    Choose your scale according to your demand load profile.

    Modern monocrystalline PV panels are 15% > 18% efficient at 1000W/m² input. Inverter efficiency is usually 10% lower than what they say on the wrapper


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    #40
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    Sir Liamalot wrote: »
    I think charging a car is a red herring.
    Yes, lets just take it as a representation of a load for a time period. SO how many kWh would you estimate?

    On that basis what is the array size estimated to be? I know that there is a lot of variables but the average EV doing average mileage will require an array size closer to 8 m sq. or 200 m sq. ??
    There is a big difference.


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    #41
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    2011 wrote: »
    the average EV doing average mileage will require an array size closer to 8 m sq. or 200 m sq. ??

    Are you questioning my maths? They are very straight forward.

    But again (I think for the third time I mention this) - you won't get much solar PV on a dark rainy day in winter. What 8m2 PV can produce in summer might be more than 200m2 can do on the worst day of year.

    Same for my hot water. I use lots and lots of it and almost all of it is heated by the sun from April to October. But almost zero of it is heated on a rainy dark December day


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    #42
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,532 Mod ✭✭✭✭2011


    unkel wrote: »
    Are you questioning my maths?

    Not at all. I am trying to get an idea of what size array would be required and I have been offers 2 conflicting answers. I accept thy both maybe based different variables.
    But again (I think for the third time I mention this) - you won't get much solar PV on a dark rainy day in winter. What 8m2 PV can produce in summer might be more than 200m2 can do on the worst day of year.

    Sure.
    Let’s talk average kWh delivered @230 volts ac per 24 hour period in ireland with your 8 m sq. array (accounting for losses).


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    #43
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    2011 wrote: »
    Let’s talk average kWh delivered @230 volts ac per 24 hour period in ireland with your 8 m sq. array (accounting for losses).

    You see that's where the problems arise.

    An 8 panel system is 8 * 300 = 2400wp. Which south facing in say Dublin, would generate about 2.4MWh per year. On average that is 6.5kWh per day. More than plenty (including any losses) to charge your car with the 5kWh it needs for its daily drive

    But you won't be going very far in winter, in fact you might have to park your EV up for days on end in December and on a good day you might only make it to the shops and back :p


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    #44
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    Average would be a 4kWp system.
    For a houshold demand of 10kWh a day.
    ~20m² Array (can be multi-aspect)


    2011 wrote: »
    Let’s talk average kWh delivered @230 volts ac per 24 hour period in ireland with your 8 m sq. array (accounting for losses).






    463434.jpg


    Solar Powah Calculator


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    #45
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    463438.jpg


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    #46
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    That's a 1.2kW system, so you need to double those figures for an 8 panel (2.4kwp) array. So 5.5kWh daily average after all losses (enough to charge your car with 5kWh after an additional 10% loss for charging). But on a really bad day in December you don't get a lot over 0.0kWh :p


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    #47
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    unkel wrote: »
    . But on a really bad day in December you don't get a lot over 0.0kWh



    Oh you do but yer inverter eats it.


    My DC coupled solar can trickle charge in Winter.
    Direct drive Mwahaha! :p:p:p


    My AC coupled solar uses grid lecky, running as a parasitic load sometimes just feeding the inverter self-consumption.
    In December 150Wp DC coupled usually performs better than 550Wp Grid Tied.


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    #48
    panman2019
    Registered Users Posts: 3 ✭panman2019


    Hi how much is it to get solar panels now for a 3 bed .

    Depends on use per year, if your going through 4500 kw per year proably need 3-4KW system i have 4KW with battery storage of 5.7KW and that cost me €10k before grant of €3800.

    is it worth it?


    Yes if payback isnt too long in first place

    How long do the panels last?

    30years

    can you sell back to the grid?

    From mid 2021 yes

    and how much grant is there.
    €700 per KW up to 4 KW and €1000 back on battery storage

    PM me for more info if you like


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    #49
    dmessiah
    Registered Users Posts: 16 ✭dmessiah


    panman2019 wrote: »
    Hi how much is it to get solar panels now for a 3 bed .

    Depends on use per year, if your going through 4500 kw per year proably need 3-4KW system i have 4KW with battery storage of 5.7KW and that cost me €10k before grant of €3800.

    is it worth it?


    Thanks
    My elec bill is around 180 for 2 months what kind of savings would i get.

    Also how long will the grant last to

    And who did you use.

    Thanks


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    #50
    unkel
    Registered Users Posts: 64,775 ✭✭✭✭unkel


    Yeah the calculation is:

    need = 6kwp


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