Battery Gas

[Alphacarina]

I had a car battery blow up in my face many years ago. So apparently batteries do outgas, and when making a spark, like when you are putting jumper cables on your battery, that's all it takes to make a nice big boom!

No question they gas . . . . and that it can be explosive

From the time I was a small lad (long time ago) everyone has always recommended placing your positive jumper cable wire on the battery positive and then connecting the negative cable last . . . . and hooking to to some grounded piece of the car engine/chassis as far away from the battery as possible. That way if you do cause a spark when making that last connection, it's as far from the battery (and it's explosive gases) as possible

Don

[Alphacarina]

Don, I have no "scientific" links for ya but the hydrogen is produced by electrolysis, from the water(H2O) in the battery ...so if the hydrogen is released, so is the oxygen, thus a hydrogen/oxygen mix...along with some sulfur from the acid....

No doubt there Jack

When the battery produces Hydrogen (and probably half as much Oxygen as well) there is no doubt that the hydrogen gas will rise up and away from the battery because it's lighter than air . . . . Out the vented cap, but the Oxygen produced is heavier than air and thus would tend to stay within the air trapped at the top of the battery

I was just looking for some scientific proof that Oxygen actually makes it out of the battery - The main reason I asked was because even after a pretty thorough Google search I couldn't find anything which supported that

Don

[brian_bp]

Many batteries are sold as 'sealed' and gel...

does that mean they do not out gas, or just that they don't need water added like the older batteries did?

There are varying levels of "sealed", from older flooded-cell batteries that just didn't have easily removed caps (and were supposed to last without adding water), to more modern Valve-Regulated Lead Acid designs. Current products such as Absorbed Glass Mat (AGM) and "gel cell" batteries (both examples of VRLA systems) manage to contain and recombine the produced gases so effectively that there is no provision for adding make-up water, and the only venting is through a pressure-relief valve; in normal operation, nothing comes out of them. They don't even need to be kept upright.

The Optima line is the AGM battery commonly discussed here, but there are several brands.

Operation is not always "normal", so venting is still advised for safety, but VRLA batteries don't need water added.

[DaveandDebbie]

I had a car battery blow up in my face many years ago. So apparently batteries do outgas, and when making a spark, like when you are putting jumper cables on your battery, that's all it takes to make a nice big boom!

Once is all it takes. I won't take chances with outgassing ever again. My battery will always be in a vented area.

Mike...

P.S. And if you're wondering, battery gasses rise!

I'm with Mike on this one. I had a truck battery blow up in my face about 20 years ago in a well ventelated area outside only takes one spark