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solar PV system

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    #32
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    yeah, that's what I was afraid of.

    But I'm not looking for a FIT, i'm just looking for an offset. Or is that too complex for our suppliers to get their head around?


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    #33
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    You can’t expect them to understand something they get paid not to understand.
    The short answer to your question is no.


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    #34
    reklamos
    Registered Users Posts: 793 ✭✭✭reklamos


    It will be interesting to see what FIT will actually be in here.
    In some EU countries people accumulate enough electricity credit during summer, that allows them to survive during winter without buying from grid.
    As a comparison in Alabama you have to pay $55 a month for the privilege to export to grid.


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    #35
    [Deleted User]
    Posts: 21,179 ✭✭✭✭ [Deleted User]


    Her old folks in Germany get a very generous FIT and they buy back that energy in Winter to run storage heaters, works a treat.

    They have 14 Kwp max but they have 3 phase to the house, Paddy has to make do with 5.5 Kwp and single phase.

    German cost per Kwh is very high though which they all have to pay even those with no solar PV and this is why they don't usually install air conditioning. Too expensive to run.

    Her Parents wouldn't install AC because they're tight miserable gits , even frown upon me running a Fan at night to keep any way cool in the Attic room , her old Man even came into the room one morning to turn off the fan, this guy has 14 Kwp on his roof, you couldn't make it up !


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    #36
    Jobi1
    Registered Users Posts: 15 ✭Jobi1


    pjwhite99 wrote: »
    Could I get some info on what use think?

    I can get a 4.2 system on the roof with a 4.5 Solax battery and 4kw solax pv inverter

    After grant for 6700

    But I have been told this is way to big for me as I only spend around 900/1000 a year on my bill

    Would you think the same?

    Some other companies say this is better for me.

    2.1 on the roof with no battery after grant around 4000

    Don’t know what to do? Some help would be great thanks

    Would you mind saying who is supplying you with the system for that price PJ?

    I have a similar energy use and I'm determined to get a similar system but any quote I have got for a system with battery storage is way above €6700?

    Thanks!!


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    #37
    Neil. J. F
    Registered Users Posts: 40 ✭Neil. J. F


    Does anyone have an opinion on whether it makes sense to charge solar pv batteries with night rate electricity during the winter months?


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    #38
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    Yes IMHO it doesn’t make sense. Take the cost of the battery and divide by number of expected cycles times the usable capacity. That should give the cost per KWh. My calculations say it ranges from 6-10c. Then take into account the inverter inefficiencies ~90-95% in and out. It gets pretty marginal.


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    #39
    Alkers
    Registered Users Posts: 6,811 ✭✭✭Alkers


    garo wrote: »
    Yes IMHO it doesn’t make sense. Take the cost of the battery and divide by number of expected cycles times the usable capacity. That should give the cost per KWh. My calculations say it ranges from 6-10c. Then take into account the inverter inefficiencies ~90-95% in and out. It gets pretty marginal.

    But if he already owns the battery?


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    #40
    unkel
    Registered Users Posts: 64,802 ✭✭✭✭unkel


    Alkers wrote: »
    But if he already owns the battery?

    The life of a battery is simply put a number of cycles. So if you use your lithium battery just for your solar (no charging up on the night rate), the battery might get 400 cycles per year, and with a 6,000 cycle expected battery life, it will last 15 years. If you charge it up an additional 200 cycles per year on the night rate, the battery will only last 10 years. And if you do the sums on this, the savings are barely worth your while. That is garo's point. And it's a good one.

    Personally I reckon that the cycle life figures of lithium batteries are on the low side, they typically represent a degradation of about 30%. After which the battery still is very useful (and not to be written off or replaced). Also when your battery has degraded after 10 years, it is quite likely you can add another battery to it (or replace it) for far less than batteries cost now. If you follow this slightly more optimistic line of thought, then yes, you will save money by (partially) charging up your battery from night rate in winter. I plan to do this on my lead acid battery (or at least experiment with it), but that battery didn't cost me anything.


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    #41
    thos
    Registered Users Posts: 574 ✭✭✭thos


    Just updated my battery config to charge a few units off the night rate from tonight. Will see how it works tomorrow.


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    #42
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    What battery and inverter do you have? Let us know how you get on.

    I haven’t switched to night rate yet so even though I believe my Pylontech + Growatt combo allows for this, there is no point playing with it yet.


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    #43
    thos
    Registered Users Posts: 574 ✭✭✭thos


    GivEnergy, 5.2kwh battery.
    System only allows to set the 'charge time', no control over discharge times. So on the basis that it's a 2.5kw max charge rate, and a ~5kwh battery, I'm setting to charge for 2hrs, ending at 9am in sync with the end of night rate, so hopefully that accomplishes the same thing.
    The car should be finished charging by that time also, so hopefully spreads out the load. Let's see.


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    #44
    Gumbo
    Moderators, Society & Culture Moderators Posts: 38,464 Mod ✭✭✭✭Gumbo


    even today, with that rain and cloud in Dublin, i'm still powering the house base load and sending 110w to the immersion.
    Not mega, but its the difference between turning the gas boiler on this evening for hot water and not.


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    #45
    thos
    Registered Users Posts: 574 ✭✭✭thos


    Must be a nice low base load. Does 110w really do much? Obviously better than nothing, but I'm envisaging a 100w bulb sitting underneath a 300l tank trying to heat it.

    Barely getting 400w off my 5.2kw array in North Co Dublin today. Base load hovering around 500w mark. No surplus, no battery being charged. Welcome to winter.


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    #46
    Gumbo
    Moderators, Society & Culture Moderators Posts: 38,464 Mod ✭✭✭✭Gumbo


    thos wrote: »
    Must be a nice low base load. Does 110w really do much? Obviously better than nothing, but I'm envisaging a 100w bulb sitting underneath a 300l tank trying to heat it.

    Barely getting 400w off my 5.2kw array in North Co Dublin today. Base load hovering around 500w mark. No surplus, no battery being charged. Welcome to winter.

    Mines a 3 kw system in Finglas, completely south facing.
    Over the course of the day I suppose it will heat the water enough for 2 showers, at the very least its only topping it up from yesterday.


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    #47
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    Alas it is laundry day here so 12+ KWh imported from the grid today and battery is empty.


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    #48
    thos
    Registered Users Posts: 574 ✭✭✭thos


    thos wrote: »
    GivEnergy, 5.2kwh battery.
    System only allows to set the 'charge time', no control over discharge times. So on the basis that it's a 2.5kw max charge rate, and a ~5kwh battery, I'm setting to charge for 2hrs, ending at 9am in sync with the end of night rate, so hopefully that accomplishes the same thing.
    The car should be finished charging by that time also, so hopefully spreads out the load. Let's see.

    Well, it works, and my sums were close enough, took 1hr 50mins to get from 4% to 100%. So that's good to know.

    Wrong day for it though! Nevermind, the car was here to soak it up anyway.


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    #49
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    Finally took the plunge. Got the kit delivered last night, install happening tomorrow.
    4.2kw (14 x 300w), 5kw hybrid inverter, diverter, 2.4kw pylontech battery.

    This time next week, I will be oil free at home. That alone should save me about 1.5k per annum.


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    #50
    lola85
    Closed Accounts Posts: 667 ✭✭✭lola85


    TheWonderLlama wrote: »
    Finally took the plunge. Got the kit delivered last night, install happening tomorrow.
    4.2kw (14 x 300w), 5kw hybrid inverter, diverter, 2.4kw pylontech battery.

    This time next week, I will be oil free at home. That alone should save me about 1.5k per annum.

    That’s optimistic!


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    #51
    unkel
    Registered Users Posts: 64,802 ✭✭✭✭unkel


    Oil free? :eek:

    In a typical household, you will save maybe 300-400 on your oil and electricity bills per year in total with your setup. Not bad, but let's not get your expectations up to levels that will never be met.

    How much did your system cost you after the grants?


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    #52
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    around 8k for the system.

    I have a little trick on my plumbing though. When water in cylinder gets to temp, a pump kicks in and pumps it through the rads, heating the house. With the diverter, this should happen without the need for oil burner kicking in. (fingers crossed)


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    #53
    bunderoon
    Registered Users Posts: 663 ✭✭✭bunderoon


    What ltr capacity is your hot water cylinder and Kw of the immersion element?


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    #54
    unkel
    Registered Users Posts: 64,802 ✭✭✭✭unkel


    TheWonderLlama wrote: »
    around 8k for the system.

    Not the worst, but certainly not the cheapest for your setup (see the quotes thread)
    TheWonderLlama wrote: »
    When water in cylinder gets to temp

    What temp? From now on until sometime in March, your full cylinder (what size?) will never reach even 50C except on a dozen or so very sunny days.


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    #55
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    definitely not the cheapest, but the installer was recommended, so that's worth more.

    Have the stat set at 75, but i have a solar thermal panel also, that usually gets it to 35-40. Diverter should help to get it to temp then it heats the radiators.


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    #56
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    Congratulations. I agree with others that the 1.5k per year saving figure is wildly inflated. €400 is a more realistic figure. I had the system installed two months ago and can already see the impact shorter days are having. And with a 2.4kWh battery you won’t get much beyond 10pm most days. You will save a bit more due to the diverter + special plumbing but doubt it will be more than 100€.

    Out of curiosity, do you pipe bathing water into the rads? Where does it return? You original post has me confused as to your setup with solar thermal and a diverter. I would have through the diverter heats up the hot water cylinder directly rather than the water circulating in the roads.


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    #57
    KCross
    Registered Users Posts: 12,072 ✭✭✭✭KCross


    I think you're in for a cold winter! ;)


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    #58
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    TheWonderLlama wrote: »
    around 8k for the system.

    I have a little trick on my plumbing though. When water in cylinder gets to temp, a pump kicks in and pumps it through the rads, heating the house. With the diverter, this should happen without the need for oil burner kicking in. (fingers crossed)

    Very nice ideea...

    Tried to do myself but my solar cilinder was with only one coil.
    With two coils, you can have the secondary circuit and achieve as you explained.


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    #59
    wexfordman2
    Registered Users Posts: 2,541 ✭✭✭wexfordman2


    TheWonderLlama wrote: »
    around 8k for the system.

    I have a little trick on my plumbing though. When water in cylinder gets to temp, a pump kicks in and pumps it through the rads, heating the house. With the diverter, this should happen without the need for oil burner kicking in. (fingers crossed)


    Sounds interesting good luck with it and let us know how you get on. Ine if your challenges re using the diverter to what your roads, is that you will be looking for this when you get the least amount if solar and need the max heat.

    That will be a challenge.


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    #60
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    garo wrote: »
    Congratulations. I agree with others that the 1.5k per year saving figure is wildly inflated. €400 is a more realistic figure. I had the system installed two months ago and can already see the impact shorter days are having. And with a 2.4kWh battery you won’t get much beyond 10pm most days. You will save a bit more due to the diverter + special plumbing but doubt it will be more than 100€.

    Out of curiosity, do you pipe bathing water into the rads? Where does it return? You original post has me confused as to your setup with solar thermal and a diverter. I would have through the diverter heats up the hot water cylinder directly rather than the water circulating in the roads.


    Separate circuit to the bathing water.

    Will be interesting to see over winter how much it does save. I take your point about shorter days alright.


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    #61
    TheWonderLlama
    Registered Users Posts: 589 ✭✭✭TheWonderLlama


    rolion wrote: »
    Very nice ideea...

    Tried to do myself but my solar cilinder was with only one coil.
    With two coils, you can have the secondary circuit and achieve as you explained.


    yeah, you need the double coil for this. Mine is actually triple as there's a range as well. My old man, who is a bit of a genius on these things, set the whole thing up. Now we get to test his system to the limit.


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