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Additional battery or more panels ?

  • 29-01-2023 7:33pm
    Registered Users Posts: 446 ✭✭

    Hey folks,

    I have €2k coming to me and was thinking of putting the few dollars into my PV system.

    I already have 16 x 370watt panels with a 5k battery and 6k inverter.

    I got a quote of €2.5k for another 5k battery. Wondering what might be a good option ?


  • Registered Users Posts: 1,333 ✭✭✭Nelbert

    Sell your existing battery and buy 20kWh DIY capacity with the money.

  • Registered Users Posts: 1,942 ✭✭✭SD_DRACULA

    Always max out the panels first then batteries.

  • Registered Users Posts: 446 ✭✭alan kelly

    Do you mean a straight swap out of battery’s ? Ie like for like then just charge off night rate during the day ?

  • Registered Users Posts: 1,333 ✭✭✭Nelbert

    I meant sell your current and add the money to the 2k and you'd likely have enough to get 20kWh via DIY.

    You'd fill the battery in 3 hours at peak generation on solar..... Charge on night rate in winter.

    Depending on your usage patterns you may be able to eliminate day rate usage throughout the year for the most part.

  • Registered Users Posts: 446 ✭✭alan kelly

    Thanks, any links for the 20kwh battery ? I assume they are handy enough to install ?

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  • Registered Users Posts: 119 ✭✭Sikie

    To enhance the payback on the battery you could also charge it during the lowest night rate windows normally 2 am onwards and discharge the same kWh back to the grid first thing in the morning to free up the battery for the next day's solar to maintain the house for the evening

  • Registered Users Posts: 1,333 ✭✭✭Nelbert

    There's a thread on a 10kWh battery self build.... You'd be doing two of them. Not for everyone but if you a handy DIY wise it's very doable.

  • Moderators, Home & Garden Moderators Posts: 4,917 Mod ✭✭✭✭graememk

    Still one, but in a 16s2p configuration vs just a 16s1p

  • Moderators, Sports Moderators Posts: 18,112 Mod ✭✭✭✭slave1

    Dunno, given the night to day rate differential now there's a lot to be said now on peak shaving Oct-Feb which is all battery

  • Registered Users Posts: 26,440 ✭✭✭✭GreeBo

    How often is your battery full?

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  • Registered Users Posts: 20,388 ✭✭✭✭ELM327

    If you're already full enough to be off grid in summer , extra panels arent going to make you off grid in winter, but more batteries will allow the most cost savings by load shifting. Make sure you're on a Day Night meter and get the best rate

  • Registered Users Posts: 446 ✭✭alan kelly

    I have only recently started using the battery to charge at night and feel like ive been introduced to whole a new world. I'll start reviewing over the next week on usage etc.

    I am on a day night meter but also can send power back to Electric Ireland at 21c so its a split decision at the moment.

  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    are grid-tied PV installations still limited to 6kw?

  • Moderators, Sports Moderators Posts: 18,112 Mod ✭✭✭✭slave1

    No, they never have been

  • Moderators, Sports Moderators Posts: 18,112 Mod ✭✭✭✭slave1

  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    I thought ESB networks limited it to 6kw for single-phase line?

    they treat up to 6kw as microgenerators, but anything above as mini-generation which has a different set of rules and won;t qualify for a grant.

  • Moderators, Sports Moderators Posts: 18,112 Mod ✭✭✭✭slave1

    From ESB Networks

    Connecting Mini-Generation

    Mini-Generation is the term which applies when an electricity customer installs inverter connected generation, within the range covered in the definition below, at a premises for the purpose of producing electricity. These generators are generally installed to locally produce clean electricity primarily for self-consumption, thus reducing the need and cost of purchasing electricity. Mini-Generation allows customers to take action to address the issues of climate change, rising electricity prices and reliance on fossil fuels on our journey to a clean electric future together. 

    Mini-Generation is designed to operate in parallel with the electricity network and is defined as a source of inverter connected electrical energy, and all associated electrical equipment, in the range as follows:

    • 25 amperes (6kVA) to 72 amperes (17kVA), when the connection is single-phase 

    Bold bit by me

  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    thats mini-generation, but isn't domestic PV under micro-generation?

    Micro-Generator is a source of electrical energy which operates in parallel with ESB Networks LV System and rated up to and including:

    25 amperes (≈6kVA) at low voltage [230 volts] when the connection is single phase

    I remember distinctly asking the installer about this at the time and he said the max allowed was 6kw. Now, that might have been a grant issue, but it seems that ESB Networks operate a different connection basis for anything above 6kw so kind of ties in.

  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    Aha! this seems to explain it,

    connections up to 6kw are inform and fit, under and NC6 form but anything over 6kw has to go through an approval process under NC7.

    Grid connections for Micro-generators

    Grid connection for projects up to 6kW (single phase, usually domestic) and up to 11kW (three phase, usually farm or commercial settings) is provided for through ESB Network’s existing simple notification process, the "Inform and Fit" process.

    On 17 December 2021, ESB Networks commenced a pilot of a new simplified process to enable customers to apply for Mini-Generation connections to the distribution network. This process is for the connection of inverter connected generators above 6/11KW and up to a maximum of 50kW. Customers can apply by submitting the Mini-Generation Application Form (NC7).

  • Registered Users Posts: 20,388 ✭✭✭✭ELM327

    Again, that's only for grid connected inverters that can export.

    You can connect one main hybrid inverter with a CT, and set export to zero. You could actually have multiple parallel inverters all configured to not export. The NC6 (and NC7) limits are pretty clear that it is based on two factors, grid tied and export capacity. Once you're not exporting more than 6kW peak to the grid you're fine and within spec. This is only really a problem in summer months if you don't have somewhere to put the excess energy anyway.

    A smart way of doing it, which I've been theorizing, is 3 parallel solis inverters installed, all hybrid, and all set to max 2kW EPM. That means it's within the regulations. You won't get the grant for it because SEAI make up their own rules, but it's perfectly within NC6.

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  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    thats what I was asking about, grid tied exporting limit. So its staying at 6kw unless i want to pay a grand and involve ESB Networks. Fine.

    But i can have more pv than 6kw on my roof, going to inverter(s) provided that the total export is no more than 6kw. Any excess just gets dumped unless i put it into batteries?

  • Registered Users Posts: 20,388 ✭✭✭✭ELM327

    There is no excess. The inverter(s) are simply configured to only take in enough DC from the inverter as needed. It's not like a wind turbine for instance, where the energy is generated regardless and has to go to a dump valve if batteries are full.

    I have 8.14kWp on my roof right now and intend to double that in the next 12-18 months. I know of other boardsies that have multiples of that 8 on their rooves!

  • Registered Users Posts: 550 ✭✭✭TheWonderLlama

    grand, thats kind of where I am going too, but just wondered about this limitation.

    Sorry about the thread hijack, Alan Kelly!

  • Registered Users Posts: 1,207 ✭✭✭denismc

    For those of you that have upgraded your systems did you find it easy to sell on your old panels and inverters?

    I have 8 X 260w panels that were installed 5 years ago, I would love to upgrade but I am not sure if anyone would be interested in 5 year old panels and my inverter.

  • Registered Users Posts: 20,388 ✭✭✭✭ELM327

    There's always a market for inverters for sure. I wouldnt buy used panels but again there's a market for them - I do think that used inverters hold their value better. Perhaps the difference is it;'s a lot easier to install the inverter yourself but most folks would get a roofer in to do panels.

  • Registered Users Posts: 1,200 ✭✭✭DC999

    Yeah, someone here sold theirs a few months back. Sold the ones that came with the house and they upgraded them. Handy for DIY for people to add to flat roofs. You'll see it here if you track back:

  • Registered Users Posts: 1,759 ✭✭✭Neurojazz

    14.4KWh batteries for less than 2k here.

  • Registered Users Posts: 4,521 ✭✭✭con747


    Don't expect anything from life, just be grateful to be alive.

  • Registered Users Posts: 63,556 ✭✭✭✭unkel

    Fixed price, no offers allowed of €150 per cell plus €18 postage. So €168 in total. Times 16 cells = €2688

    How is that less than 2k?

    It is you selling them, isn't it? So you will accept an offer of €1900 including shipping?

    And FWIW, it is allowed to sell your stuff here in the forum, but we have a dedicated thread for for sale / wanted stuff. Also it is generally considered to be polite if your ad is on DoneDeal / rather than eBay, as those sites are owned by the same company as boards. Not really nice to promote one of their competitors when they allow you this facility for free...

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  • Registered Users Posts: 8,124 ✭✭✭micks_address

    depending on what invertor you have you might not be able to plug and play all batteries.. one downside of my system (givenergy) is that i can only use their batteries.. which is obviously more expensive.. im already tempted to add 3 more panels to my south east array but ive only had it 3 months so common sense would stay sit tight for at leat 12 months and see how generation looks like in summer etc