venting battery holder of hydrogen

[Peter]

To increase space I’ve relocated my batteries, approx. 300amp/hr plus a separate engine start battery to a new water proof, and nearly air tight battery holder in the bilge’s, on my yacht.
My problem is how I vent the battery compartment to remove hydrogen realised during charging. I have a number of ideas ranging from putting a simple vent in the battery holder lid going through the floor into the main cabin, allowing the holder to vent directly into the bilge’s to “piping” together the vents on each battery then running a common vent line through the floor.
I would appreciate any good ideas on which would help me resolve this issue. Thanks for your comments.

Peter

 

[rogerm]

From what you say I gather you have the type of battery that provides a small poly pipe for venting and is sort of sealed otherwise. In that case just add a 'Y' piece (as used for car windscreen washers) to connect the two batteries and continue the pipe. Put a down pointing end, to the nearest point where the hydrogen can dissipate without going near anything hot. Hydrogen will rise of course being the lightest of gases. Even just up the back of a bunk will usually be sufficient unless you have smokers aboard......
Roger

 

[kgi]

peter dont forget that hydrogen is highly flammable so you also need to make sure the boat as awhole is well ventilated. personally i think i would fit some type of extended vent tube to bring the vent above saloon floor level, because murphys law states, vents below floor let the water in as well as the fumes out!!! keep the light shining!!!!! keith

 

[pvb]

A good way of doing this is...

A good way of doing this is to have tubes going from opposite ends of the battery box to vents positioned high up on the outside of the boat (cabin sides or cockpit coamings). In most conditions, you'll then tend to have a small but effective airflow through the battery box.

Don't vent it inside the boat if you can help it. Remember that batteries produce both hydrogen and oxygen when gassing - a ready-made flammable mixture. If you do decide to vent it inside the boat, use one of those fuel tank vents with a flame-arrester gauze in it.

 

[ccscott49]

Hydrogen is highly explosive, you do not want it in your cabin! Vent the boxes to the outside atmosphere, Hydrogen being lighter than air, will disperse fairly quickly. A smallish pipe will do, but as big as you can fit, unobtrusively. However the amount of gas produced during normal cycling, wont be much. Mine dont have vents, they are open to the engine room and that is acceptable, as long as the engine space is well ventilated.

 

[johnsomerhausen]

I have my two batteries in plastic battery cases in a compartment under the chart table on my boat; I have a plastic hose that goes to the inside of the cockpit tub. Justr in case of heavy weather, I have a plug to close the exit of tube so that sea-water doesn't get at them.... Since, as Roger wrote, hydrogen rises very quickly, I don't think there is any danger of explosion even if I'm smoking in the cockpit.
john

 

[HaraldS]

have exactly the same arrangement: 7 batteries under the floor and collecting all into one hose which goes to the dorade vent of the engine comparment.
Definitely works. A year ago I had a yard do some work under the floor and they accidently disconnected the hose at some point. I now know that it does trigger the LPG alarm. I have a two sensor alarm with one sensor at the oven and one under the pantry floor. Very goog to knowt hat battery gas gets detected.