Extracting hydrogen from battery comp .

[Halo]

I agree with Antarctic pilot. Never heard of battery charging generating enough hydrogen that it facilitated an explosion. Hydrogen is the smallest atom and will rise and diffuse at an amazing level. It would be more useful to work out how to prevent lightning strikes

 

[John the kiwi]

Has anyone actually experienced a genuine hydrogen explosion?

I agree that this should be a non problem unless you have made deliberate attempts to make the apartment gas proof.
OTOH
I am one of the few that has seen a battery explosion. In my apprentice days we had battery forklifts where the battery was a set of 50 odd lead acid cells in a steel case and with exposed links between cells. Straight off the charger, the driver lifted the steel battery cover which was about a metre square and touched a terminal! Just 7 of the cells blew up showering acid and broken plastic in all directions. The driver was shielded by the very cover that caused the problem and we were all just far enough away to be unhurt. Sobering stuff though!
Also, who at Lansing Bagnall forklift manufacturers couldn't see that a steel cover over uninsulated terminals might be a potential problem?

 

[thinwater]

...If you can perceive hydrogen (how ?) ....

The most common way is that it can set off a carbon monoxide monitor (interfering sensitivity). I hear of this occasionally, normally when a batter is going bad and overcharging.

 

[thinwater]

Has anyone actually experienced a genuine hydrogen explosion? ....

Yes. It required a seriously non-vented compartment (forepeak glassed in and gasketed--battery for thruster), switch gear in the compartment (dumb), and hard charging bad battery. The battery was undamaged, but the V-berth was soft (crack in support).

Even a small vent would have prevented it. As you say, hydrogen goes up FAST. I used to work in a plant where chemical reactions generated large amounts. It was gone in seconds. Live steam rises fast , and hydrogen is many, many times lighter than 212F steam. Think of it this way--hydrogen has weight of about 1/14th that of air. A very hot flame has a weight about 1/5th that of air. Hydrogen rises faster than a flame. For think of a helium balloon. Same idea. Hard to hold it down.

ABCY, USCG, and ISO all require battery venting, but do not require fans.

 

[AntarcticPilot]

I agree that this should be a non problem unless you have made deliberate attempts to make the apartment gas proof.
OTOH
I am one of the few that has seen a battery explosion. In my apprentice days we had battery forklifts where the battery was a set of 50 odd lead acid cells in a steel case and with exposed links between cells. Straight off the charger, the driver lifted the steel battery cover which was about a metre square and touched a terminal! Just 7 of the cells blew up showering acid and broken plastic in all directions. The driver was shielded by the very cover that caused the problem and we were all just far enough away to be unhurt. Sobering stuff though!
Also, who at Lansing Bagnall forklift manufacturers couldn't see that a steel cover over uninsulated terminals might be a potential problem?

Sounds like a steam explosion caused by short circuiting the battery, though.