batteries off gassing too much

fiddlehead
fiddlehead Solar Expert Posts: 29 ✭
in Off Grid Solar & Battery Systems #1
Not sure yet of the exact problem here. Battery bank is 16 UL 16's. One 2" vent fan wired to turn on and off at a certain voltage (26 volts I think??) One Bergey 1000 watt turbine, 1600 watts of PV. This system has been in place for about 5 years. Everything has been working well. They expanded their system and added another 1600 watts of PV. They also determined that one battery was bad and replaced that one battery. I mentioned that if that was the case, they would want to replace the whole bank.

Of course time goes by while they make there decision. Now we have lot's of sun and some wind lately. CO alarms are going off in the house and it seems like the batteries are off gassing a lot. Water level is good, fan is working. They have had this happen a few times and sometimes the CO alarms go off in the middle of the night, even if there is no wind. Almost like they are off gassing even after the vent fan is off.

I am going up to the system to have a look in a few days and any insight on battery off gassing would be helpful. More vent fans for the battery bank size, new bank altogether??? Anything would be helpful.

Thanks
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: batteries off gassing too much

    although i agree the battery bank may be old and in need of replacing, but to set off alarms when no charging has been taking place sounds suspiciously like there may be another source of gassing taking place, like maybe a gas stove or even a propane or nat gas leak.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: batteries off gassing too much

    Also CO detectors have a limited life of five to ten years...

    Is the detector ok? Can it even detect hydrogen gas?

    Are the detectors mounted low or high (hydrogen gas being very light).

    I worry that you may be drawing reverse draft on a propane or wood fired appliance and bringing in carbon monoxide. If the place is very air tight, it is possible your battery exhaust fan is pulling the air in.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #4
    Re: batteries off gassing too much

    I too wonder about the age of the CO detectors, is it just their low battery alarm going off? They last a fraction of the time that smoke detectors do.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • fiddlehead
    fiddlehead Solar Expert Posts: 29 ✭
    #5
    Re: batteries off gassing too much

    It is the batteries and nothing else. I have seen this issue before with CO/ smoke detectors (new or Old) where the offgassing of batteries has caused them to go off. Those cases were easy because the folks were not venting at all. I like the idea of an appliance maybe not being vented properly.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #6
    Re: batteries off gassing too much

    So Carbon Monoxide detectors are also triggered by hydrogen????
    Extremely interesting if so. One gas being very heavy, the other very light, and totally, completely different, gasses.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: batteries off gassing too much

    Some gas detector pick up CO2, HS, and even high oxygen levels. Depends on the detector involved.
    And yes charging a battery can set them off.
    Frankly, CO2 detectors are over-rated. New propane refrigerators are required to have these complete with gas shut-off. They fail far too often. What good is any safety device if it is unreliable?

    It can take some tedious investigation to find out exactly what is causing the problem.
    Buy a new one; see if it is triggered too. That will eliminate the defective unit possibility.
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  • fiddlehead
    fiddlehead Solar Expert Posts: 29 ✭
    #8
    Re: batteries off gassing too much

    So is it true that the batteries will not off gas anymore at the end of it's life as it does when it is new?
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #9
    Re: batteries off gassing too much

    Check the vent fan,, perhaps there is an obstruction in the vent line.

    Tony
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  • fiddlehead
    fiddlehead Solar Expert Posts: 29 ✭
    #10
    Re: batteries off gassing too much

    One time when this happened the firefighters that were there trying to get the gasses out of the house told me they felt air blowing out the vent fan hole. That's right, I forgot that I got a call at 10 at night because they had called the fire department. There instruments detected the gasses as well.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #11
    Re: batteries off gassing too much
    fiddlehead wrote: »
    So is it true that the batteries will not off gas anymore at the end of it's life as it does when it is new?

    Older the battery is, the more sulphated, the less exposed plate. This adds up to less electrode-to-water contact. It will draw less current (zero, in some cases) and produce less gas.

    Many's the time I've put a dead battery on charge and crank the Voltage way up then watched as nothing happened. :p
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