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Batteries in the attic

  • 24-03-2022 10:51am
    Registered Users Posts: 2,261 ✭✭✭

    Just wondering if it's a problem with weight, the attic is not converted just your standard wool/wood joists and chipboard I placed down in the middle for storage.

    If I put 180kg worth of batteries on the boards/joists, will it be able to handle that or will I expect them in the bedrooms shortly after?


  • Registered Users Posts: 455 ✭✭KieferFan69

    The hell are you doing up there, why so much power ?

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    20kwh is not that much.

    And well 🤬 if these numbers are correct:

    I think they are 2x4s.

  • Registered Users Posts: 9,761 ✭✭✭Effects

    Can you attach any brackets to the walls for support?

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    They are server rack batteries so they don't have brackets.

    But I was thinking that, what kind of heavy duty "shelf" rails are out there that I might be able to use?

  • Registered Users Posts: 9,761 ✭✭✭Effects

    I understand that, but I meant some kind of standard steel bracket to support, rather than placing them on the floor. What dimensions are the batteries?

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  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    481*535*140mm times four of them.

    Yeah that's what I am looking for now and the only thing that I found is air conditioning unit wall brackets that hold up to 200kg which might do the job.

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    Think I will go for these, they seem to be doing the job, 600mm length

    Might even go triple arm instead of two to spread the weight even more.

  • Registered Users Posts: 41 fluffykre

    Hi  SD_DRACULA I was having the same thoughts this week about the weight of batteries on the roof joists. Are you going with Pylontech server rack batteries? If so there maybe custom racks out there which can mount

    this website seams to load slwly however there's cached version of the racks page

    Maybe you could source something like that and then have cantilever arms installed under it to give some extra support

  • Registered Users Posts: 11,050 ✭✭✭✭the_amazing_raisin

    Wouldn't the simplest option be to build a little platform on top of the joists to spread the weight? Put the platform joists perpendicular to the ceiling joists and place the battery rack in the middle

    FWIW I've two water tanks in the attic which probably weigh over 200kg when full and they're supported in the same way

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost

  • Registered Users Posts: 5,114 ✭✭✭homer911

    I'd be nervous of the temperature changes and impact on the batteries, more than the weight issue. Ask any EV driver, heat is a killer of battery life and cold impacts capacity. Attics go through great temperature fluctuations

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  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    I do like the look of those pylontech wall racks, and the batteries do look almost exactly like the pylons (dyness) but I doubt it will beat the 50 euro for the cantilever arms.

    I am pretty sure if I spread the load like @the_amazing_raisin it will fine also, my installer concurred and he made a valid point, while they were working on the system there, two of them would weigh more than 180kg and I didn't see them fall through to the bedrooms 😂

    In any case this is probably temporary until I shift the whole PV system to my shed so I can do the attic (maybe with a flat roof so I can convert N roof to S and add more panels 😁)

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    Not too worried about that, it's well insulated and had a battery for one year in there without issue.

    Lifepo4 optimum temps are 20-50c anyway and they are rated to go down as far 0c which the attic never reaches.

    I do wonder if you actually need space between each battery rack or just sitting on top of each other is fine, 9 times out of 10 that's the way I see them in YT, etc, just stacked on top.

    Post edited by SD_DRACULA on

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    Each arm rated 243kg so I "should" be ok in theory 😁

  • Registered Users Posts: 189 ✭✭connesha

    While I haven't done it yet, I was also planning on putting a DIY 20kwh pack into the attic, over a supporting wall, cross the joists to spread load, osb on that, and finally a sheet of fireboard over the osb.

    While fireboard doesn't seem necessary with LiFePO4, the installers did put 2 layers under the PureDrive, so may as well use it rather than dump it...

    There a 60 gallon water tank up there for a long time already, done similarly.

  • Registered Users Posts: 11,050 ✭✭✭✭the_amazing_raisin

    "The internet never fails to misremember" - Sebastian Ruiz, aka Frost

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

    Yeah it should do, they're not hollow blocks.

    Will still put 3 short table legs under the end bits because I am that paranoid.

  • Registered Users Posts: 67 ✭✭delmonte4

    How did you get your batteries into the attic in the first place? Trying to move one up and it seems awkward no matter what I do

  • Registered Users Posts: 7,275 ✭✭✭MrMusician18

    People should check their house insurance as some forbid having kit in the attic

  • Registered Users Posts: 67 ✭✭delmonte4

    Any suggestions lads?

  • Registered Users Posts: 2,261 ✭✭✭SD_DRACULA

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  • Registered Users Posts: 1,996 ✭✭✭jkforde

    2 people if possible, even if just for the initial up the stira part!

    mind your back however you do it!

    🌦️ 6.7kwp, 45°, SSW, mid-Galway 🌦️

  • Moderators, Sports Moderators Posts: 18,814 Mod ✭✭✭✭slave1

    wrap a blanket around it and pull up with two people in the attic and another guiding it from below, I do this with all awkward shapes, its just a case of spreading the load and having a good grip

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