Batteries in the attic?

Thick8Thick8 Registered Users Posts: 47 ✭✭
I want to move my battery backup system into the attic. I am in the process of finishing that space as a living area but can section off part of it for the batteries. What would I need to do to make that work? venting, spill mitigation, etc. Is there a building code established for doing this?

Comments

  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    Assuming the sectioned off attic area is likely to get hot, a couple additional things to note; battery life expectancy is severely reduced with heat, and proper temperature corrected charging voltage will be important.

    Sturdy plastic tub(s) would likely work for spill mitigation. I imagine venting required for heat mitigation would be more than enough for venting gasses.

    Building code varies by jurisdiction (and sometimes by specific individual inspector), but other than requirements for conduit etc. I'm not sure there's anything saying you can't (assuming system voltage of 12-48v). I've run across inspectors who seem to approach things such that if it isn't specifically allowed, it's prohibited. Luckily (or not, depending on your POV) I don't have to worry about inspectors though. Others who do may know more than I.
    Off-grid.  
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  • Dave AngeliniDave Angelini Solar Expert Posts: 4,137 ✭✭✭✭✭
    Sure go ahead and do it. I just hope you never have a need to use your home insurance policy. Maybe you do not have one and so at least do what Estragon suggested. If it is conditioned living space the battery needs to be listed for this also.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
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  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    Estragon, I currently have my battery bank in a non-climate controlled (way) detached garage. It gets over 100F in there. The attic is well insulated so It doesn’t get as hot. I was thinking of building a small room to house the batteries and inverter. Then run a duct from the crawl space beneath the house (which is encapsulated and dehumidified) straight up to the attic to better maintain a constant acceptable temperature. I would also vent the room above the roofline. I would probably use a plastic A/C air handler pan to hold the 3 8D batteries. Then I could put a drain line on it in case of leakage. 
    Just wondering if anyone has done something like this.
  • mcgivormcgivor Solar Expert Posts: 2,423 ✭✭✭✭✭
    Why not use the crawl space for the battery location? 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    I was thinking a tub with enough excess volume to contain (at least) the volume of a rupture and acid leakage of all batteries in the unlikely event of same. I wouldn't have a pre-installed drain (as a potential leak), but rather deal with the contained situation if it occurred..

    As @mcgivor asks, why not put batteries in the crawlspace? It would likely be easier to run wire to the attic than ducting, and ducting from crawlspace introduces potential for earth gasses being forced into living space.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
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  • littleharbor2littleharbor2 Solar Expert Posts: 1,112 ✭✭✭✭
    Plus lugging a bunch of heavy batteries into and out of the attic sounds like an unpleasant job.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    I did think of that but the crawl space is only about 2’ tall with an 18” access hole. And where I would need to place them is about 40’ from the access. Also I wouldn’t check on them as often as I would in the attic. Plus building an enclosure to remove any outgassing would be difficult at best. 
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    Why would they need to live 40' from the access?
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  • mcgivormcgivor Solar Expert Posts: 2,423 ✭✭✭✭✭
    Having worked in many attics in the past as an electrican, I've never encountered a cool one in the heat of summer, even with insulation, but then again I didn't work in yours. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • mike95490mike95490 Solar Expert Posts: 8,030 ✭✭✭✭
    Up the ladder, over the ceiling and through the sheetrock !

    Attics are not designed to carry much more of a load than a box of holiday ornaments.  putting hundreds of pounds of batteries in it, is going to cause problems - according to my crystal ball.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • WaterWheelWaterWheel Registered Users Posts: 291 ✭✭✭
    Like Mike said that's a lot of weight for an attic.      And I assume that you also plan to move the inverter to the attic to keep the battery cables short, rerun your panel wires, and probably move the charge controller too.      Throw in rerouting the AC wires that your inverter is putting out and that's quite a job.

    If you're going to do all that it may just be easier to use a water bath and keep the batteries in the garage.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    I like the idea of a water bath. Would I need to run a little 12 volt pump waterfall to gain evaporative cooling of the water. I have an extra PC water cooling pump and some corrugated plastic panels. The pump only draws 1 amp and I could put it on a sunload sensor.
  • WaterWheelWaterWheel Registered Users Posts: 291 ✭✭✭
    edited September 12 #14
    With only 3 batteries you could get a large plastic tote from Walmart.      That's what I use for a solar system at my shop with 3 batteries but I don't keep them in water.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    edited September 13 #15
    I don't think the weight is a problem. The house was built in 1950 with the attic designed to be a living space. It is all tongue in groove decked over full dimension 10"x2" spaced at 16" OC. The location that I plan to place the batteries is over the original location of the oil furnace. So it is basically a 3'x3' floor the ceiling room placed directly over a 4'x4' brick pier. Plenty of support I think. I don't have a ladder, I have a full 36" wide staircase that I put in. I guess calling it an attic is not exactly correct.
    The inside breaker panel is located in a space that used to be a doorway from the kitchen to ( what was originally) the housekeeper's room. Which is right next to where the oil furnace was. I just cut access holes to the panel and floor to run a 6/3 cable for my new Leaf charger. So it would be a simple task to move the circuits that I want on the backup to new circuit box next to the existing one.
    My question is really about the codes governing the batteries being in the house as apposed to located in a garage or remote location.
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    AFAIK, at least in my jurisdiction, there's nothing in the code beyond the electrical stuff that would apply wherever the batteries live. That may change if/when R.E., powerwalls, etc get common enough that bad things happen and code responds, but for now it appears to be crickets.

    If pulling a permit for the work, you might want to run it by the assigned inspector. In a past life I did heritage building restorations and conversions, in which uncommon things came up pretty frequently. For the run of the mill stuff, the inspectors were fairly predictable in what was likely to pass, but they varied a lot when it came to dealing with the uncommon conditions.

    You may also want to check insurance conditions. My policies are silent on the issue so far, but may be worth checking.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,137 ✭✭✭✭✭
    Batteries can not be in conditioned space unless they are listed for it in most of the United States. If you have a fire, and the insurance company hires someone like me, they have the option of not covering the claim.  Of the 3 I have done, one was not covered.

    It is a dumb idea to do this in my most humble opinion.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
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  • softdownsoftdown Solar Expert Posts: 1,928 ✭✭✭✭
    Absolutely horrible idea for so many reasons I can't even begin to start on.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    Fortunately my wife is an adjuster for our insurance company. She didn’t find anything that excludes a backup system. She also said that in order to deny a claim, the battery bank (if it were done without a permit) would have to be the source of the claim, and as long as it passes inspection it is covered. Solar panels require a separate endorsement though. So that answers the insurance question.
    How many here have batteries in their finished basement or on the wall that separates the garage from the living space? Are these installations against code? Trying to figure out why the second level of a home is a no-no and these other installations are acceptable. Guess I’ll have to go digging through building codes. Yuck...
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    The basement would normally be considered conditioned space. Lots of basements have batteries for alarm systems, UPSs, etc., but AHJ may require ETL certification for such systems.

    A garage would normally be unconditioned space, with code requirements for fire separation etc., so not directly comparable to an attic space (unless you're planning similar fire separation products and assemblies between the battery space and living space).
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
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  • softdownsoftdown Solar Expert Posts: 1,928 ✭✭✭✭
    Roof trusses are generally made of 2 x 4s that span a large gap. They are not designed to hold the compact weight of lead batteries. Roof truss failure would be unimaginably catastrophic. Ask a roof truss manufacturer about your plans and see what they say.

    Attics are also very hot. The batteries would suffer a very short life as a result.

    The safety of lugging heavy batteries up and down a steep attic ladder? What do folks think?

    This is about the worst idea imaginable. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    edited September 15 #22
    softdown said:
    Roof trusses are generally made of 2 x 4s that span a large gap. They are not designed to hold the compact weight of lead batteries. Roof truss failure would be unimaginably catastrophic. Ask a roof truss manufacturer about your plans and see what they say.

    Attics are also very hot. The batteries would suffer a very short life as a result.

    The safety of lugging heavy batteries up and down a steep attic ladder? What do folks think?

    This is about the worst idea imaginable. 
    I described the space in post #15. Reading before slamming is always a good idea.
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    2x10s at 16"OC and a 4' span would support orders of magnitude more weight than 3 x 130# batteries.

    Even assuming they were put on plywood spanning the bottom chord of 3-4 2x4 trusses, a dead weight load of ~ 400# wouldn't be my first concern. Trusses that couldn't take the weight of a couple of guys working in the attic would be firewood IMHO..
    Off-grid.  
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  • bill von novakbill von novak Solar Expert Posts: 814 ✭✭✭✭
    Thick8 said:
    I don't think the weight is a problem. The house was built in 1950 with the attic designed to be a living space. It is all tongue in groove decked over full dimension 10"x2" spaced at 16" OC. The location that I plan to place the batteries is over the original location of the oil furnace. So it is basically a 3'x3' floor the ceiling room placed directly over a 4'x4' brick pier. Plenty of support I think.
    For a while we had a bank of 24 T105's powering an airport.  We had a wooden box built to hold the batteries, vented to the outside.  The fans failed within about 2 years due to acid mist.  When we decommissioned the system the plywood under the batteries was black. When a worker got the first 4 batteries out he got into the battery box to get the next few out.  His foot went through the 3/4" plywood below.

    Imagine that happening to your house.
  • mike95490mike95490 Solar Expert Posts: 8,030 ✭✭✭✭
    Your post is titled  Batteries in the Attic.    Then you complain when you are told the attic is a poor choice for MANY reasons.
    The next comeback is it's a finished 2nd floor, with stairs, and such, supported by a brick pier.   But that's still not a good place to put batteries.
      So don't get all huffy about an answer to a question  you asked.  

    Good luck and have fun.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    mike95490 said:
    Your post is titled  Batteries in the Attic.    Then you complain when you are told the attic is a poor choice for MANY reasons.
    No complaining at all. I better described the area to eliminate the confusion understandably caused by the title. And again asked if ther were codes established governing this type of installation.

    The next comeback is it's a finished 2nd floor, with stairs, and such, supported by a brick pier.   But that's still not a good place to put batteries.
     Asking someone to quantify their opinion is not a comeback; it is part of intelligent productive discourse.


    Good luck and have fun.
    Thank you and I usually do.

  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    edited September 15 #27
    Thick8 said:
    I don't think the weight is a problem. The house was built in 1950 with the attic designed to be a living space. It is all tongue in groove decked over full dimension 10"x2" spaced at 16" OC. The location that I plan to place the batteries is over the original location of the oil furnace. So it is basically a 3'x3' floor the ceiling room placed directly over a 4'x4' brick pier. Plenty of support I think.
    For a while we had a bank of 24 T105's powering an airport.  We had a wooden box built to hold the batteries, vented to the outside.  The fans failed within about 2 years due to acid mist.  When we decommissioned the system the plywood under the batteries was black. When a worker got the first 4 batteries out he got into the battery box to get the next few out.  His foot went through the 3/4" plywood below.

    Imagine that happening to your house.
    Yes that would be bad. 
    When I built a hidden gun cabinet I lined the entire enclosure with spray-on bed liner material. That might not be a bad idea for a battery enclosure. Fire retardant bedliner sprayed on fireboard.
    You also just made me realize that any ductwork to remove fumes would need to be made of an acid proof material. Metal ductwork would be a no-no.
  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    My plan for ventilation is a fan on the intake side with PVC pipe. With bottom intake / top exhaust, I think it should vent naturally most of the time, but I'll put a computer muffin fan on the intake to pressurize the box a bit to assist.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
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  • Thick8Thick8 Registered Users Posts: 47 ✭✭
    That makes the most sense as long as the enclosure is sealed so that all the ventilation air flows out the pipe. Using convective current for airflow would probably work as well. I remember seeing one of those rooftop spinning ventilation “fans” made of plastic with ceramic bearing for move positive ventilation if needed. 
    Some schedule 80 4” PVC bringing stable low temperature air up from the encapsulated crawlspace. Up to an acid and fire proof enclosure. Then out through a roof vent.
     I could mount the inverter/charger and charge controller outside the box with only the 2 cables passing through the wall of the enclosure.
    Thanks for the ventilation idea. 


  • EstragonEstragon Registered Users Posts: 3,039 ✭✭✭✭✭
    As well as temperature (warm air rising) hydrogen produced by batteries is lighter than mostly nitrogen ambient air, so should normally vent naturally out the top.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • jonrjonr Solar Expert Posts: 1,132 ✭✭✭✭
     > Using convective current for airflow would probably work as well.

    In the Winter, but may reverse when the AC is on (80F air doesn't passively rise through a vent surrounded by 100F air).   Probably more of a concern is things that lower interior pressure (eg, kitchen/bathroom fans, dryer). 

    On the other hand, I once did the calculations and for anything larger than a small room, hydrogen levels typically can't get high enough to be a problem.   But don't rely on this.

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