Vents from bat box

Chris11
Chris11 Registered Users Posts: 130 ✭✭
in Solar Beginners Corner #1
I'm building a plywood battery box in my pumphouse for two marine bats.  

Do I need one vent tube or two, one from each side?  And what size piping?  

Thanks, Chris
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    you have two things to vent, explosive gas, which will flow uphill on it's own, and heat from charging/discharging the batteries,  Don't cook the batteries in a DIY oven.
    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 ||
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  • Chris11
    Chris11 Registered Users Posts: 130 ✭✭
    #3
    Thanks for the reply but heat shouldn't be a problem since I use it mainly on the weekend, and even then very little.  I even thought that perhaps I don't need a bat box for the gas since the pumphouse is well ventilated....but for just a few hours work I want to be safe.  

    I'm simply stuck on what size to make the vents.  
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    2 vents 3" di at / near the top of the box would be enough.  Even a loose fitting lid, or using a pencil as a spacer under the lid would vent the gas well. Hydrogen wants to dissipate and rise.
    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 ,

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,917 ✭✭✭✭✭✭
    #5
    Just adding to Mike, the space you are venting to and the size of the bank are very important. You would not want to vent a 48V 1,100 AH bank into a small shed that was not vented.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
    FWIW I have a old (1987) sailboat with two GC house batts and a 12v start batt in a really small unventilated box over which I like to enjoy a cigar and a sundowner, which has yet to blow up. Assuming "marine" batteries are a couple of 6v 200ishAH GC type batteries in a reaonably well ventilated space I'd put a divider between the batts and the pump relay box and call it a day.
    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
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  • Chris11
    Chris11 Registered Users Posts: 130 ✭✭
    edited October 2016 #7
    Thanks all.  Originally I had put the two bats about waist high on a counter I built.  Directly above the bats I mounted the 2500/5000 inverter, bottom of inverter about 6" from tops of bats.  Controller just to the right of the inverter.  It was at this point I though that if a spark occurred in either of the electronic boxes my old body would be at risk.  So I dismantled all since the well is now "winterized" and decided to put a plywood box around the bats with some piping to the outside of the pumphouse.

    I've made my decision.....2" black plastic pipe in and out since I have some leftover from plumbing the well etc.   As an added bonus I'll run it up the outside of the pumphouse and with it being black it should absorb the sun's heat and created a passive vent system.

    Thanks mike95490  for giving me the information about size.
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