Do drained Alkaline batteries emit gases?

It's that time of year to give away gifts again. For the last few years I have given away flashlights to pretty much everybody. I have had a few twisty 1xAAA keychain light gifts come back to me because the front glass was shattered. Two people said they actually heard a loud "pop" when it happened (in their pocket). I was reading online that if a flashlight is not used for a long time, gases can build up inside the flashlight and create a pressure that breaks the front glass. I guess my question is this: does a "dead" battery emit any gasses? I'm looking at a 1xAAA flashlight that has a switch with obvious parasitic power drain, but wonder if that might be a good thing? If I give away 1xAAA keychain lights as presents to people who "never" use their lights, then maybe a parasitic drain is a good thing? What do you think?

It would be more appropriate to post this question in the batteries section of the forum.

You could always gift them with lithium AAA's if you wanted. I actually just had an off brand alkaline do something strange in my E01. I took it on a plane and afterwards there was a small hole in the bottom of the cell, scoring on the floor of the light and no continuity between the negative spring and the body. I reseated the spring and it was fine after that but all that to say yes, one thing alkalines are great at is emitting.

Yes, alkalines can emit hydrogen gas when they leak that is why some flashlights have a pellet in them to absorb the gas as they have to be certified explosion proof. If the gas isn't leaked then there still is pressure inside the cells that could later leak. parasitic drains are never a good thing but are the side effect of having electronic switches in them which can be a good thing if the parasitic drain doesn't cause the batteries to be drained before needing to be used. If the light is a twisty 1AAA it doesn't have parasitic drain as the twisty switch lights have no power flowing and neither do the clicky switch lights have power flowing when in off position.

Yeah, often referred to as a "battery fart". I've seen it happen from a reverse charge in a 2AA light - it just puffed up the rubber boot. I'm surprised 1AAA can break a lens. Reverse charge on a 2CR123 can result in a little pipe bomb though.

reppans said:

Yeah, often referred to as a "battery fart". I've seen it happen from a reverse charge in a 2AA light - it just puffed up the rubber boot. I'm surprised 1AAA can break a lens. Reverse charge on a 2CR123 can result in a little pipe bomb though.

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I have experienced that with NiMh as well.

yep, hydrogen

Sometimes they fizz, or fart, I've had a energizer AA industrial that emitted noise like a cicada for almost a minute while sitting unused on the shelf.