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Q & A: Do automobile batteries out-gas?

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Most recent answer: 01/22/2014
Does a standard 12V car battery produce gas that it released? I believe the term is off-gas. If this does happen, is it only when the car is being operated? Can it happen if the car has been parked for a few days? Thanks
- Dennis (age 58)
Phoenix AZ

Hello Denis,

An automobile 12V battery in decent condition should not emit gasses either in normal discharge mode or when not in use.   However if you overcharge the battery it will start an electrolysis reaction and produce an explosive mixture of hydrogen and oxygen.   Here is a website that has more information than you want to know about lead-acid batteries: 



(published on 01/22/2014)

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