batteries: venting and insulating?

hi. i'm about to go off the grid in a small houseboat. i have four crown flooded batteries, and i'm not sure how concerned i need to be about the design of my battery box. there is a good possibility that the part of the boat it is located in will be below freezing at times. how cold can my batteries get before i need to worry about them?
in terms of venting, what is the minimum venting i can do? i could penetrate the wall to send a vent to the outside, but i'd definately prefer not to.

if i do need maximum venting, and i also need maximum insulation, then i have a problem right? because the two contradict each other!! ahh. please help. if anyone has suggestions or a battery box design that they've used i'd be forever indebted!!!

adam
928 830 6565

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: batteries: venting and insulating?

    Batteries with only 50% charge, will not freeze at 0F

    You battery box needs to let you access water fill ports, and clean/torque terminals.

    The "box" is mostly to divert acid vapor/mist from charging, to someplace safe, instead of into the engine bilge and alternators. The amount of hydrogen from properly charging batteries is really pretty low, but the box vent should disperse it too.
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  • System2
    System2 Posts: 6,290 admin
    Re: batteries: venting and insulating?

    so what is the defintion of a 'safe place"? can i just vent the
    batteries out of the box and into the room if it is a living space or
    do i need to get the vent outside? thanks
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: batteries: venting and insulating?

    Acid fumes in my living space - no thank you.

    In a boat, just snake a vent tube to a new vent - a rise uphill will encourage hydrogen to rise, and you won't need a fan. http://www.zephyrvent.com/ for info.
    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 ,

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: batteries: venting and insulating?

    Small battery banks won't produce enough hydrogen to worry about, UNLESS they are in very confined spaces. A Mike suggests, a Zepher fan coupled to a small vent will more than suffice.

    On the other hand, a battery bank of this size in open air shouldn't put out enough gas to worry about, but it certainly won't put out "acid fumes" much beyond the foot print of the batteries. A boat is a closed enough space that I would provide some positive venting if only for the piece of mind.

    T