Battery box venting.

[Spookies]

Hello everyone,

So my batter boxes are in the trailer, under my bed. Fully sealed and just made the holes on the floor.. do I have to vent them all the way out thru the bellypan or is that fine just to vent them under my floor?

Thank you

[uncle_bob]

Hi

When a battery outgases, one of the products is hydrogen. It's significantly lighter than air. The vent path needs to be "up" to allow it to escape.

Bob

[Protagonist]

If you only use AGM batteries, it won't matter. They don't outgas enough hydrogen to come anywhere close to the Lower Explosive Limit for hydrogen (4% by volume) or to suffocate you by displacing the oxygen inside your trailer. In fact, on the T1N model Airstream Interstates, the house battery box was under the passenger-side front seat and not vented to outside at all— but the house battery had to be an AGM battery.

[Spookies]

Originally Posted by Protagonist

If you only use AGM batteries, it won't matter. They don't outgas enough hydrogen to come anywhere close to the Lower Explosive Limit for hydrogen (4% by volume) or to suffocate you by displacing the oxygen inside your trailer. In fact, on the T1N model Airstream Interstates, the house battery box was under the passenger-side front seat and not vented to outside at all— but the house battery had to be an AGM battery.

Hi, thank you so much for tje reply. I have 2 Inerstate batteries group 27. So what should I do?

[Spookies]

Originally Posted by uncle_bob

Hi

When a battery outgases, one of the products is hydrogen. It's significantly lighter than air. The vent path needs to be "up" to allow it to escape.

Bob

Thank you Bob

[Mollysdad]

Ever seen a battery explode?
Here's the short version. Large lead acid car type battery being used in the field to power electronics. It was in a wooden box connected to an automotive battery charger.
I had just left the area when I heard "BOOM", very similar to a shotgun firing or a firecracker in a garbage can. I raced back to find the operator flushing his eyes with a water bottle he had nearby luckily. He was disconnecting the charger, got a spark inside the wooden box and "Ka-boom".
I called the paramedics, but he insisted he was fine and refused to go to the hospital. Later that day he told me his clothing dissolved, so he had to return to the hotel to change.
No vents in the wooden box. That changed soon.

[Spookies]

Originally Posted by Mollysdad

Ever seen a battery explode?
Here's the short version. Large lead acid car type battery being used in the field to power electronics. It was in a wooden box connected to an automotive battery charger.
I had just left the area when I heard "BOOM", very similar to a shotgun firing or a firecracker in a garbage can. I raced back to find the operator flushing his eyes with a water bottle he had nearby luckily. He was disconnecting the charger, got a spark inside the wooden box and "Ka-boom".
I called the paramedics, but he insisted he was fine and refused to go to the hospital. Later that day he told me his clothing dissolved, so he had to return to the hotel to change.
No vents in the wooden box. That changed soon.

We are not venting the batteries in a wooden box, we have actual sealed batter boxes that comes with a hose(venting kit). My question is where to vent them.

[Protagonist]

Originally Posted by Mollysdad

Ever seen a battery explode?
Here's the short version. Large lead acid car type battery being used in the field to power electronics.

Lead acid type. Wet cell. The hydrogen concentration inside the box was somewhere between the lower explosive limit (4%) and the upper explosive limit (75%) If the OP uses wet cell batteries, then yes the box needs to be vented top and bottom. And the top vent needs to go up and to the outside with no dips where hydrogen can accumulate.

If he uses AGMs, it just has to be vented for pressure relief as air pressure changes, not vented to get rid of hydrogen. But it should also be clearly labeled, "FOR AGM BATTERY USE ONLY" so the next owner doesn't try to put wet cells in a box only suitable for AGMs.