Ventilated Battery compartment for AGM's?

Discussion in 'Boat Design' started by Mat-C, May 9, 2012.

  1. Mat-C
    Joined: May 2007
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    Mat-C Senior Member

    Just a quick query, wondering whether (sealed) AGM batteries have to be in a ventilated compartment the same as traditional lead-acids do?
    I know it would be good practice to do so, but just interested in what the ABYC etc have to say on the matter...
  2. BPL
    Joined: Dec 2011
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    BPL Senior Member

    Good question. Following the thread to see the answer.
    AGM batteries don't outgas day to day, but they could pop the vent caps if overcharged.
  3. CDK
    Joined: Aug 2007
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    CDK retired engineer

    No actual ventilation is required if the compartment contains only batteries and/or the lid or top cover isn't sealed. In the event of overcharging or overheating, a popped vent will discharge hydrogen and oxygen like any other LA battery.
    Because hydrogen is the lightest element on this planet, it will escape immediately through any small hole or gap above the batteries.
  4. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    Yes..ventilate to prevent overheating. AGMs dont like to get hot.
  5. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    Can they be put in passenger compartment below?

  6. BertKu
    Joined: May 2009
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    BertKu Senior Member

    If you charge with a constant Voltage charger and stay below the 13,8 Volt there is no ventilation needed , as you stay below the gassing Voltage. Your batteries cannot be overcharged nor over heated. But most people are too impatience to wait for 24 hours or more to have the battery fully charged and are using the normal 14,4 Volt alternator, thus the risk is for an overcharge and overheating is there and ventilation , even with a Sealed Lead Acid battery is needed.

    Should you charge with a solar system, constant Voltage charging could be an option.
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