Deep cycle off gas

I'm betting on during charge only.

All that are enclosed in a camper are vented to the outside. I think
this tells the story if you want to be safe.
Brian

Mine only gassed when charging.

It's the charging side. Off gassing occurs because of electrolysis of the water in the battery. Excess current causes the water to breakdown into hydrogen gas and oxygen gas. This gas is then released via the vents. Sealed batteries off gas as well, but the gases are recombined within the battery and the resulting water is reabsorbed into the mat making them maintenance free.

Interesting Google article. Most gas generation is during the charge cycle but the battery will discharge and out gas at a very small rate, even when sitting.

Good ventilation and water maintenance seems to be the common denominator of all battery articles.

Jebby14 wrote:
hey all. help settle a debate here. Do flooded batteries (think deep cycle camper batteries) off gas during usage or only during charging? we are discussing the safety of using one to provide power in an enclosed space.

Provide an enclosure with a vent to the outside.
When I built the battery box for 2 X 6V batteries that I keep inside, I did some research on the amount of hydrogen gas that I had to deal with for venting. I don't have the references anymore but my take was that there is not that much hydrogen to vent. A smallish vent on the top of the box and an airway toward the bottom, will allow the lighter hydrogen to vent adequately.
You do have to vent the box, however. A mixture of hydrogen and atmosphere will develop a potentially explosive gas. If the hydrogen pools at all, you reach the combustion lower limit very quickly.

When I did a cargo trailer conversion, I mounted the battery under the bed in a vented battery box. I believe it came from AdventureRV.Net. Never smelled it or had a problem.