Hydrogen gas generated by overcharging a battery

Demonstration of "hydrogen bark" so named as the sound resembles a dog's bark from the explosive combustion of hydrogen and oxygen gas in an open test tube. 2 amperes at 15 volts fills the tube in less than a minute.

[@user-jd8uq4rt9j]

Can it fill balloon to fly can you make video about it?

[@megaleadjp]

hydrogen gas needs to be at 4% concentration to explode

[@chrisw1462]

Did you know that you can buy custom cell caps that catalytically recombine the hydrogen and oxygen into water? One brand is called Hydrocap. hydrocapcorp.com/

[@chrisw1462]

Yes, and where would that hydrogen go if you didn't collect it in a tube? You didn't tell or show how long it took to collect it, but I'll be it was a good bit longer than the few seconds you showed before the cut, even with the current protections you bypassed (and probably cut the life of your battery significantly). Hydrogen is so light it would quickly rise and mix with air, which is why that tube leads outside the box. In normal charging the release is so slow as to be negligible with one battery this size outside of a small space. Yes, you still don't want to take stupid chances, but please present all of the facts instead of just trying to instill fear.

[@PeterPete]

i've read when charging a sealed lead acid battery the sides can bulge due to the production of hydrogen gas! why doesn't anybody include the production of hydrogen gas when detailing the reactions in a lead acid battery when charging that's what i want to know!

[@chrisw1462]

@@PeterPete Because the acid inside is far more dangerous than the hydrogen. If you see a bulging sealed battery, there's usually so little hydrogen there that, by itself, if it did ignite, you might get a small burn. The acid being splashed all over if a battery explodes from pressure is much more likely to cause you permanent harm.

[@PeterPete]

@@chrisw1462 tks for replying - i probably haven't made myself clear but there is obviously hydrogen gas being produced as a result of charging a lead acid battery. So my question is, why don't the chemical equations relating to the reactions in a lead acid battery during charging detail the formation of hydrogen gas? Any ideas?

[@chrisw1462]

@@PeterPete Ah! Sorry! You're correct, it should be in the discharge equation but is usually left out because, being ionic in solution, it's not really involved in the reaction. The SO4 that combines with the lead is leeched from the sulfuric acid, H2SO4, which leaves the H2 to roam around (which it was already doing, really) until the battery is charged. I do agree with you: The charge equation has to include it, so the discharge should as well.

[@PeterPete]

@@chrisw1462 there's clearly something not quite right with the equation or the understanding with what's going on in the reaction inside a charging battery!