Battery storage box

I have my battery bank for my cabin stored in an deck box beside the cabin
I lined the box with plastic the styrofom under bank & on the sides.

-should I vent the box in the summer & winter?
-as of now it's not air tight so there is gas getting out
-as for winter we get extended cold -35c is possible should I do more?

thanks Craig


  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Battery storage box

    1) you've made a dupicate post (or else there is such a subtle difference, I can't see it)
    edit and delete the other one.

    2) Depending on how "tightly" your deck box is built, I suspect if it's average construction, it's got plenty of air leaks, and only your monthly EQ would need to have the lid open.

    3) outdoors, -35c is pretty cold for lead acid. the battery bible at:
    If your charge *EVER* gets below 75%, and its' -35, you are right at the freeze point.
    Fully charged, you should be good to -67 (if the paper is right !)

    4) at those thermal extremes, you better have a "Battery Temperature Sensor" (BTS) connected to your charge controller, they are only $20 or so.
    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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  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Battery storage box

    I don't remember your battery configuration, but if you are using temp compensated float charging over the winter, I wouldn't think much venting would be needed. A small button vent on the top and near the bottom should be fine. Also, since the box is outside, sources of ignition are reduced.

    As I think about this, at -35 the absorb/float voltage might be quite high, so gassing might be higher than during the summer. My own batteries have been in a shed covered with a styro-foam box unvented for years. My current set is under a bench in the house with a voltage controlled fan venting the box to the outside.

    If others chime in with other opinions, perhaps a call to Trojan tech support might give you some help.

  • BB.BB. Super Moderators, Administrators Posts: 33,313 admin
    Re: Battery storage box

    Craig, Mike,

    It's OK--I practiced with my "Super Moderator Powers" and deleted the duplicate thread.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Battery storage box

    thanks for your help guys, a remote temp sensor must be purchased, as for the rest a small vent in the winter and make sure the panels are clear of any snow or ice,
    the rts will lower the absorb & float voltages in the cold weather?
  • BB.BB. Super Moderators, Administrators Posts: 33,313 admin
    Re: Battery storage box

    Actaully, the remote temperature sensor will increase the voltages in winter (specifically cold batteries).

    It will help ensure that your batteries are fully (and properly) charged in the winter...

    In general, most good Charge Controllers have internal temperature compensation too... But, since the Charge Controllers pass relatively large amounts of current--they tend to be hotter than their environments (and the batteries)... So without the BTS/RTS, the batteries tend to not be fully charged without the BTS.

    Also, in the cases where the batteries are hot (heavy current draw/charging) the battery voltage drops--and you can get thermal run-a-way where the controller thinks more current is required because the voltage is falling. Probably not a big chance of this happening--but it is possible.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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