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Solar PV battery options

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Comments

  • Registered Users Posts: 5,201 ✭✭✭ championc


    Solar panels will easily support batteries twice the panels kWp

    However, with FIT, you really only want to get as far as midnight to get to the night rate period



  • Registered Users Posts: 6,468 ✭✭✭ the_amazing_raisin


    Yeah I don't really see any issues with having the bigger battery, the system should be cheaper to run and gives you a bit more flexibility in the evening when you're running out of solar



  • Registered Users Posts: 6,468 ✭✭✭ the_amazing_raisin


    For anyone who bought battery cells from PWOD, is there any advantage to buying from the EU warehouse other than delivery time?

    Ordering from China is a few hundred cheaper, but if I get hit for VAT or other taxes then it's probably not worth it


    Is there any difference in the customer service or consumer protection between the two?



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 59,685 CMod ✭✭✭✭ unkel


    Ordering from China, they take off the VAT. You're supposed to get hit with it when the batteries land in Ireland, but they are coming via Poland so this often doesn't happen 😁

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 1,316 ✭✭✭ THE ALM


    We started with a 5kWh battery to see how we went and it certainly helped smooth out the consumption.

    We have recently replaced the 5kWh with 9.8kWh and think it is (probably) ample to see us through most evenings with about 40% remaining before any meaningful production covers our base load. Come the darker months we will start load shifting and hope to cover our day time usage before the night rate kicks in.



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  • Registered Users Posts: 17 aleesi


    I think your baseline is when the battery powers the house all the way until night rate kicks in for the corner case (no production at all) which would mean 500/30 = 16Kwh. Which will allow to only import at the right rate.

    Your PV/inverter are also important, i.e. max KWp and Max char. current so you understand how long it would take for the battery to charge during the day. Finally the batt price. 16KWh off the shelves could cost you 10K (puredrive) or less than half if you go the DIY route.

    As a rule of thumb, for a 5/6Kwp system with 100A output the sweet spot would be 10KWh. You could charge the battery and use the immersion at night rate (which would prob cover 70-80% of your consumption) and be mindful with power hungry appliances when dark. In December a system like that would still produce on average 4-6units a day (KWh) depending on location and orientation, which means 0 production some days 7-9kwh if you get to see the sun for a couple of hours... So keeping an eye on the forecast and planning ahead will keep the battery alive all the way till night rate.

    If you get the batteries at the right price I'd go for the 16KWh...



  • Registered Users Posts: 4,415 ✭✭✭ paulbok


    Leaving aside FIT considerations, for my setup (6.9kwh array + 4.8kwh battery), I reckon a 7.2kwh battery would be the sweet spot to maximise PV usage vrs cost, however there isn't a huge difference in a 2.4 and 4.8kwh additional battery (according to the supplier) if I was going to upgrade.

    i was close to getting another 4.8kwh battery earlier in the summer, but with FIT, I'm probably not going to for the foreseeable future.



  • Registered Users Posts: 1,621 ✭✭✭ bullit_dodger



    Totally agree Paul. I'd be very slow to go for a large "off-the-shelf" battery. That said, I think you can make the math work on these existing tariffs, (e.g. Energia's €0.079 night and €0.28day) but you need to have a significant usage to be able to cycle those batteries during the day. And who's to say that they will remain like that.

    For laughs though.....10Kwhr (assume 8.5kwhr usable) and 10% losses will save you (8.5 * 0.90 * (€0.28 - €0.078)) = €1.54/day. Call it €500 year......if you did it for every single day. That's not bad.

    I think 5-8 Kwhr is about the goldilocks alright for off the shelf. DIY on the other hand......well people have their own reasons for doing it, but I reckon 20kwh is a good ballpark. Cover the house for a full day (ideally captured off solar!)



  • Registered Users Posts: 424 ✭✭ DC999


    I think it's making sense to load shift all we can to night (to reduce buying day units and cleaner juice then in general), and then send as much as possible to FIT land. Unless you've a large setup or don't have an EV, or are low usage house (which is a good thing)...most are not gonna be paying tax over the €200 limit I'd guess. 

    New Energia D/N night rates are 13c - called them the other day and the 8c ship has sailed, ye lucky sods :) But if a night unit is 13c and FIT is a few cent more, it's pretty much easier to load up at night and sell FIT during the day. The new D/N day rate is 43C. Saucy!! So the battery helps reduce that of course.



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 59,685 CMod ✭✭✭✭ unkel


    @bullit_dodger - "I think you can make the math work on these existing tariffs, (e.g. Energia's €0.079 night and €0.28day) "


    Aye. That's what I'm on and with a 20kWh battery. Currently heating the house still from battery fully charged last night and topped up from PV during the day. I will have to fine tune / home automate it a bit as some days I will come up short and will have to start the gas boiler to help as I do not want to use €0.28 day rates to use for heating where I can use €0.08 night rate or €0.08 gas

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



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  • Registered Users Posts: 1,004 ✭✭✭ poker--addict


    so my system will be good to go next week, panels, hybrid solis inverter, no battery.

    I am not in a rush to get a battery but that is where my attention will be now.

    I know it is not the most difficult thing but I don't have the time to do a total DIY job requiring monitoring batteries, balance batteries, playing with amp meters, worrying about management systems etc. So I suppose I will be looking at power-wall type setups which are more or less plug and play. Is the equivalent of a pure-drive or huaiweii cheaper on Alibaba and of ok quality?



  • Registered Users Posts: 133 ✭✭ darraghsherwin


    Can GivEnergy inverters work with Seplos BMS?



  • Registered Users Posts: 17 stephenchilds


    Was just looking at a 10.4 kWh battery on AliExpress, blmpow brand. Fully assembled, BMS. etc. For around 1270 euro. Seems way too good to be true. Anyone looked into one of these?



  • Registered Users Posts: 5,201 ✭✭✭ championc


    If you found a link with that price on it, you'd be mad not to jump on it. Deffo a mistake I reckon. Most listings have a "colour" selection, so make sure you are selecting what you think you are selecting



  • Registered Users Posts: 1,004 ✭✭✭ poker--addict


    Link?



  • Registered Users Posts: 4,165 ✭✭✭ Gerry


    Can anyone recommend a storage inverter? 3-5kw

    Thanks



  • Registered Users Posts: 17 stephenchilds


    Sorry newbie mistake. All the text talks about 200 Ah / 10 kWh then the colour is 60Ah ...

    Still an interesting option at 1270ish for 3kwh if cells/BMS/case are good quality.



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 59,685 CMod ✭✭✭✭ unkel


    A battery inverter? Many of us in the forum have the Sofar ME3000SP. It can charge / discharge at 3.2kW and can handle any type of battery, including DIY lead acid and lithium ones as long as they are nominal 48V

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 2,975 ✭✭✭ graememk


    To get over 3kw your looking at a SMA one.. they are the only ones that go above that. And they are expensive



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 59,685 CMod ✭✭✭✭ unkel


    €3k plus expensive for the sunny boys!

    I bought my ME3000SP for €440 including shipping second hand about 4 years ago. You'd be lucky to get one for several hundred Euro more now though.

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



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  • Registered Users Posts: 4,165 ✭✭✭ Gerry


    thanks folks, will keep eye out for me3000sp secondhand.



  • Registered Users Posts: 607 ✭✭✭ allinthehead


    Rexel stock Sunsynk inverters, I was thinking of adding one along with a battery to my existing system.

    Anyone have any experience/opinions on these.

    https://www.rexelenergysolutions.ie/product/sunsynk-hybrid-inverter/



  • Registered Users Posts: 1,466 ✭✭✭ SD_DRACULA


    If it's true and you can get the 8kw model to work on 1 phase like it says on the docs, I'd jump on that one, having 8kw coming from batteries would be top notch.

    The max mppt voltage is only 500v which seems a bit low but it looks like they can also be paralleled easily enough.



  • Registered Users Posts: 607 ✭✭✭ allinthehead


    Unfortunately I think we can only get the 3.6kw and 5.5kw versions here.

    Price is good though at 1080 plus vat for the 5.5kw version. I was thinking of adding it to my microinverter system. It would allow me to add a string to my roof in the future too.

    Post edited by allinthehead on


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 59,685 CMod ✭✭✭✭ unkel


    Wow that is just what I need, the 8.8kW version that is. Max charge / discharge is 190A, that's glorious, almost 10kW

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 1,466 ✭✭✭ SD_DRACULA


    If we can import it then I'd say it's worth swapping out my 6kwh solis which makes me lose out on about 1kw on my 7kwp with it's 6kw limit and not to mention doubling the battery charge/discharge rates.

    If the reaction time is indeed 4ms then it would probably suck less from grid before hitting up the battery too.

    More research needed.



  • Registered Users Posts: 607 ✭✭✭ allinthehead


    There's no product code on the rexel website for it. I'll ask about it next time I'm in Kellihers.



  • Registered Users Posts: 133 ✭✭ darraghsherwin


    Has anyone confirmed if GivEnergy inverters will work with Seplos BMS?



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  • Registered Users Posts: 1,466 ✭✭✭ SD_DRACULA


    Tried it this morning when I panicked charged the battery at 100a for the last hour of night rate due to BS met.ie forecast and no charge at night.

    And what Solis said about 75A in the latest FW they pushed is also BS as you can see below:

    100a --> 70a after 15 mins, pretty stupid limitation if you ask me but I assume it has to do with their 10 year warranty



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