Ideal battery enclosure

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TakeItEasy
TakeItEasy Registered Users Posts: 8 ✭
in Off Grid Solar & Battery Systems #1
Getting ready to cut a PO for a grid-tied system with battery backup, and was wondering what people prefer for battery enclosures. Not only are these powder coated aluminum manufactured enclosures pretty expensive, but I'm not sure I want my batteries in a metal enclosure, anyway. I was thinking of building something with plywood and 2x4's with some foam board insulation. Anyone have any thoughts on this?

Thanks
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #2
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    Re: Ideal battery enclosure

    What size battery bank? What type batteries? Do you need positive ventilation (move fumes out of the room, etc.)?

    For me, I like to recommend that what ever you choose--That they leave the battery bank easy to access for installation, cell maintenance, etc...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #3
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    Re: Ideal battery enclosure
    BB. wrote: »
    What size battery bank? What type batteries? Do you need positive ventilation (move fumes out of the room, etc.)?

    And what will be the ambient temperature of the battery box?

    Depending on the answers to all these questions, it may make sense to put the box up on a stand, 18 to 30 inches off the floor. This makes for easier access and shorter battery cables.

    Make sure that all batteries are at the same temperature (is one side of the box next to a heater or a cold door?). If your batteries are on shelves, make sure the top shelf is not warmer than the bottom shelf (may require active ventilation).

    Make sure the battery cable conduit leaves the battery box BELOW the tops of the batteries.

    Make sure your battery box is not in front of or underneath your electronics and electrical panels. Sometimes the best way to comply with BOTH this requirement AND the need for short battery cables is to build a wall and mount the electronics on one side of the wall and the battery box (on a stand) on the other side of the wall.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • TakeItEasy
    TakeItEasy Registered Users Posts: 8 ✭
    #4
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    Re: Ideal battery enclosure

    The system will have 4 x MK sealed AGM 12V 245 Ah, size 8D. Project is in NY, the equipment will be in a climate controlled room. Thanks for the tip about the batteries not being under the other electrical equipment, I hadn't heard that before.

    I'm leaning towards building something out of wood, these fancy enclosures seem too expensive.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #5
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    Re: Ideal battery enclosure

    With AGM sealed batteries, just about any enclosure will work, but my typical method is to custom build a wood box with pressure treated framing and plywood skin or whatever matches the customers decor, then line it with heavy gauge - 30mil polyethyline plastic - folding the corners so there are no seams. The manufactured metal boxes look nice of course, but never the right shape it seems and with flooded batteries are going to corrode it sooner or later. Your wood box will fit exactly the space, not corrode, and be a lot more economical. Also, especially with flooded batteries, make it easy to service. Its hard enough to get people to maintain their batteries, don't make the box a hassle. Get it high enough so your not stooped over when servicing, a cover or lid that is easy to remove and give good access to all the battery caps.
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  • northerner
    northerner Solar Expert Posts: 492 ✭✭✭✭✭✭
    #6
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    Re: Ideal battery enclosure

    I built my battery box out of 3/4" plywood and reinforced all the joints with 3/4" trim pieces. The box sits on a solid 2x6" frame, but the sides and top don't need to be built super heavy. I sealed the top lid with foam tape and I ventilate the box (flooded cells) with an externally mounted (from the box) ventilation fan, that exhausts the fumes and hydrogen gas outside. It's working out great keeping the batteries inside the house, as they won't be exposed to extremes of temperature, and no need to insulate the box. There is a potential 80 C temperature differential where I live (from close to -50C in winter to over +30 C in summer)
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #7
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    Re: Ideal battery enclosure

    At my last house, the battery bank was on a re-enforced workbench inside the garage. Made it easy to maintain the batteries. The downside was the ventilation issue when I had a battery cell fail, causing overcharging of a battery.

    At this house, I had to start over again anyway, so decided to put the battery bank outside. I found an aluminum box at a local salvage yard, and purchased it for $75.

    dscn9318.jpg

    I welded up a steel support frame for the box.

    dscn9328.jpg

    Poured a concrete slab...

    concrete11.jpg

    Built an interior platform from 2x4s and 5/8" plywood.

    box8.jpg

    And loaded it with batteries.

    dscn9487.jpg
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #8
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    Re: Ideal battery enclosure

    Limited to 5 pics per post...

    Final product:

    dscn9476.jpg

    I did paint the inside of the aluminum box with a couple of coats of a brush-on bedliner coating.

    box3.jpg

    There's a vent on both sides of the box, and a solar powered 12V muffin fan to move air thru the box. I'm in sunny FL, and cold isn't an issue. The box does sit under the eave of the house, and the camper partially shades it too.

    The platform was designed with my back in mind. This height makes it easy to do PM on the batteries, and lift them in/out as needed. The support frame wasn't complete yet, so it's another inch higher now:

    dscn9325.jpg

    Rain, sun, bugs, are issues here. A wooden enclosure would work, but extra effort would need to be taken to ensure it wouldn't rot, or have carpenter ants or termites take over. I got a good deal on the aluminum one, and the size was almost perfect for my application.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #9
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    Re: Ideal battery enclosure

    One thing I like about wood/non-conductive enclosures--No chance of a short between a cable connection, wrench, and metal box.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #10
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    Re: Ideal battery enclosure

    I bulit mine with 1/2 plywood, which I siliconed all around and put weather-stripping rubber gaskets around the cover. I put some foam on the buttom for insulaton, then a sheet of plastic on top. I made an inlet on the bottom and attached a through-the-roof vent with a fan to the top. No signs of wear after a year.
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #11
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    Re: Ideal battery enclosure
    BB. wrote: »
    One thing I like about wood/non-conductive enclosures--No chance of a short between a cable connection, wrench, and metal box.

    -Bill

    That's an important consideration on a vehicle, which often has a negative grounded box. I made sure to isolate the metal box I'm using, as well as coat the inside with a non-conductive bedliner coating.

    Since I used Anderson Powerpole 175A connectors on each pair of batteries, I simply unplug them if I need to wrench on the bank. I do not like sparks!
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