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Solar PV battery options

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Comments

  • Registered Users Posts: 2,275 ✭✭✭ ECO_Mental


    The previous one was a 3 phase system so more expensive here is a 15 kWh single phase 6kW inverter one for £11,000



  • Registered Users Posts: 19,087 ✭✭✭✭ ELM327


    You'd also have vat and customs



  • Registered Users Posts: 2,275 ✭✭✭ ECO_Mental


    😯 Oh S**t they are wholesale prices EEK!!! forgot about that

    I knew the payback on commercial battery systems were bad but just wanted to confirm and run the numbers as I will be giving a small presentation at work about domestic PV systems



  • Registered Users Posts: 19,087 ✭✭✭✭ ELM327


    The best way for payback is to buy calb cells and busbars and wiring etc on aliexpress. The next best is to buy from an installer that meets the price guidelines (1k euro for each 2kWh of battery)



  • Registered Users Posts: 5,348 ✭✭✭ championc


    Commercial in many cases means 3 Phase and therefore leads you into totally different inverters



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  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,571 CMod ✭✭✭✭ unkel


    The only way I would ever even consider buying a commercial / pre made battery is if it is the smallest you can get and if the install is giving you the SEAI grant. And if I didn't have the time nor the inclination to DIY.

    It's simply not for everyone. There is something to say for a system that is owned by someone else who will fix it when it goes wrong, etc. This will of course cost you significantly more and could easily double or treble the payback time of your entire system

    11PM: 15kW o'clock!



  • Registered Users Posts: 4,218 ✭✭✭ Gerry


    After reading 20 pages plus of this thread I'm sorry that I'm none the wiser.

    If I want 5 or 10kw and I am happy to DIY, what is my best option?

    Get CALB cells from a specific seller on aliexpress

    Get a BMS

    Am I likely to have cells bulging or not having full capacity in 12 months..?

    Alternatively, if I buy a rackmount system from aliexpress, for more money, is that likely to be less reliable?



  • Registered Users Posts: 19,087 ✭✭✭✭ ELM327


    Calb cells from PWOD. BMS. At least that way you know what you're buying.

    If you buy a rack mounted system you cant know what is inside, but if going this way watch the will prowse video of the battery



  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,571 CMod ✭✭✭✭ unkel


    And don't buy a battery that Will Prowse or David Poz haven't yet reviewed, like a certain battery very popular in Ireland and the UK. I mention no names 😂

    11PM: 15kW o'clock!



  • Registered Users Posts: 1 cjxfh


    This may well have been covered earlier but have you folk advice on installing a solar pv system without a battery now but when batteries improve sufficiently adding a battery to the system. How realistic feasible and cost effective is this approach?



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  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 60,571 CMod ✭✭✭✭ unkel


    Yes you can do that. Either get a conventional system with a conventional inverter and see what the future brings. Or spend an extra €1k on the same system with a hybrid inverter so you can add a battery later without having to upgrade your inverter. Or just do the conventional system now and add a completely separate AC side battery system later (like a Tesla Powerwall, or a DIY solution with something like a Sofar ME3000SP like many in this forum use)

    11PM: 15kW o'clock!



  • Registered Users Posts: 3,364 ✭✭✭ graememk


    If your waiting on batteries to improve.. don't worry about putting in a battery.

    There isn't much on the horizon right now, any new tech will be expensive vs the tried and well tested batteries that we currently have.

    There is currently huge demand, maybe prices will go down in a few years. Or maybe not.

    To upgrade a hybrid inverter is needed or a stand alone storage inverter to use batteries.



  • Registered Users Posts: 11,415 ✭✭✭✭ DrPhilG


    And I may have a case of the jealousy.



  • Registered Users Posts: 5,348 ✭✭✭ championc


    We won't compare the cost and capacity of that vs a few Pylontechs 🤣



  • Registered Users Posts: 1,617 ✭✭✭ SD_DRACULA


    Not seeing a crazy amount of support for the top shelf 🤣



  • Registered Users Posts: 3,364 ✭✭✭ graememk


    Not going anywhere, same as the bottom and that has been in a year 😉



  • Registered Users Posts: 6 shazbot1


    Hi Graememk, are the CALB batteries on PWOD 'A' rated vs the Prismatic EVE's which always seem to say 'A or B' rated on PWOD just wondering on the CALB quality?

    I understand you don't need to compress the CALB's vs the other ones as per your pic.

    You must have a driveway full of EV's for 40KWh 😄😄



  • Registered Users Posts: 3,364 ✭✭✭ graememk


    Just the one ev.. that's away during the day.

    Most people are moving away from compression completely. (Off grid garage for example)

    The calb style are a sturdier battery, better terminals etc.

    A/b grade to me is meaningless. The cells I've got have been grand, no complaints. But I'm expecting a 180-200 cell.

    The black coloured ones have only recently appeared. Perhaps they are newer.

    I would have tried them but the blue ones were cheaper!

    I currently have the pack configured as a 750 ah pack, giving myself some buffer.



  • Registered Users Posts: 1,617 ✭✭✭ SD_DRACULA


    With the cold weather we had this week, wondering if anyone that's hammering the batteries for the 2-3 hour window at night if they saw a drop in charge rates, have seen it go down as low as 7c in the attic but charging at 15A for 9 hours they don't complain 😁



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  • Registered Users Posts: 11,415 ✭✭✭✭ DrPhilG


    I'm hammering my batteries all night but they're insulated.


    I used to get issues with my PylonTech ones though which weren't insulated and the attic could drop as low as 2 or 3.



  • Registered Users Posts: 2,923 ✭✭✭ irishchris


    Didn't notice any issues with mine but last night only needed to bring them up 30% to full as was cracking day of production yesterday so were full at the end of the day.

    They are in a battery box surrounded by 125mm solid insulation so that would help massively, plus insulated the shed they are in also in the summer but only with 50mm insulation.

    No drop off in charging other than the usual when it tapers off approaching full.

    Inverter temperature never really dropped below 20c with it being -4 here last night and checked battery temps on BMS and sitting around 13c.

    Ideally would like battery charging window longer than three hours and thankfully seems to be going this way with energia now going to four hour window with theirs.

    For 7c per kw at night with pinergy though I'm more than happy for batteries to charge at what the inverter is rated for and well below the maximum that these cells are rated for charging at. It is similar to your own setup and most people's in daytime when the sun is shining your batteries will be charging at maximum rate in the day in summer. Wouldn't consider that hammering the batteries either though 😃





  • Registered Users Posts: 1,617 ✭✭✭ SD_DRACULA


    Yeah "hammering" the batteries with a Solis 🤣 - as if it's even possible with their fake 100A rates anyway

    Got to 5c in the attic last night so might need to look at some insulation for the batteries



  • Registered Users Posts: 2,923 ✭✭✭ irishchris


    Yep not happening with a solis alright 😃15 mins at best of 100a and then 70. Still undecided on moving to a sunsynk yet due to some little issues with family members one. Plus at the minute the Solis is more than capable but will decide after seeing how rest of December goes.

    Insulation is definitely needed if in cold attic or shed alright and no bigger test to it than this week



  • Registered Users Posts: 175 ✭✭ connesha


    As long as the cell temperatures are kept in a good range, it's fine.

    Below are the temperatures for the past week, where:

    Red: the battery cell temperature (the minimum temperature of the 4 temperature probes)

    Blue: the BMS Env temperature (effectively the attic temperature)

    Green: Met Eireann temperature

    Purple: The Inverter temperature (managed by an external fan)

    Its charging some 10kwh (~65A) each night over 3 hours. Battery cells are in a box, which is insulated since October. Will take the insulation off in spring.





  • Registered Users Posts: 1,617 ✭✭✭ SD_DRACULA


    Yeah quite annoying I can't get live values (including temps) directly from the BMS, I can use a serial cable to connect to the dyness but they only provide a crappy windows app and it only gives values of the pack currently connected to.

    If only there was a way to connect the COM port to my HA server (usb to serial cable I already have) and actually read that COM port data directly into HA since solis BMS data is useless.



  • Registered Users Posts: 3,364 ✭✭✭ graememk


    Is it modbus? Do you have the registers that you could "roll your own" software



  • Registered Users Posts: 704 ✭✭✭ allinthehead




  • Registered Users Posts: 175 ✭✭ connesha


    If you cant get it from the BMS, you could use a separate temperature sensor, placed beside the cells. Something like this:

    https://www.aliexpress.us/item/3256804119999547.html

    (I'm using these on my DHW cylinder, pushed under the insulation, linked to HA, and they've been flawless)


    It may not give you the exact temperature the BMS is seeing, but it should be good enough to generally let you know if its getting too cold.



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  • Registered Users Posts: 1,617 ✭✭✭ SD_DRACULA


    Not on the COM port, I think that uses that serial communication protocol, probably something similar to the pylontechs

    https://www.home-assistant.io/integrations/serial/ this would be ideal but not sure if they use their proprietary protocol inside that .net app they sent me.

    I have a DHT sensor right beside them which probably gives me about the same readings.



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