Deep Cycle Battery Gassing

[sailinglegend]

Originally Posted by Pelagic

...Any idea how much gas we are talking about and any tricks to solve it (No nearby vents to outside)

It seems these batteries are AGMs so most of any gas produced is recombined into water inside the battery so won't leak under "normal" conditions.

These batteries are standby batteries for Telecom and Solar use, so don't expect the kind of performance you will get from good Lifeline AGMs. They are NOT designed for marine use - falling regularly off 3 meter high waves could damage them.

Not all AGMs are the same.

[steve77]

Sailinglegend - thanks, and I agree that AGMs recombine the H2 instead of venting it to the outside.

My question had more to do with flooded cells. It's common knowledge that the charging process produces hydrogen gas. However, the presenter at this seminar specifically talked about the dangers of hydrogen sulfide gas produced by charging flooded cells. Frankly, I think he was misinformed and out of his depth, but I wanted to check this forum to see if I owe the guy an apology.

Does anyone have any opinions on whether flooded cells can produce hydrogen sulfide gas?

Thanks!

Steve

[a64pilot]

Ever smell the rotten egg smell from an overcharged battery? I believe that's hydrogen sulfide, so yes they can produce it, how much? I don't know, but I bet it it's not enough to be a health issue, never heard of anyone getting sick from it.

On edit, I bet he was selling something other than flooded cell batteries, wasn't he?

[ontherocks83]

Originally Posted by a64pilot

Ever smell the rotten egg smell from an overcharged battery? I believe that's hydrogen sulfide, so yes they can produce it, how much? I don't know, but I bet it it's not enough to be a health issue, never heard of anyone getting sick from it.

On edit, I bet he was selling something other than flooded cell batteries, wasn't he?

I was curious about that too.

They do produce gas but as far as enough to be a health issue I would highly doubt.

[steve77]

I have never smelled anything from my batteries, much less sulphur. I tend to believe the earlier poster who stated the sulphur smell was actually small droplets of sulphuric acid vented to atmosphere by extreme bubbling, more than normal outgassing hydrogen, which is a result of overcharging. I do not believe it is actually H2S.

But I'm open to other ideas. How about any Navy submariners out there. Do subs have monitoring for H2S? If it were a possibility of forming, this seems like it would be included in the design of the battery rooms.

[msponer]

Its enough hydrogen to trigger our propane alarm. But only when we are charging at a dock and the batteries are nearly full. I don't know how sensitive the propane alarms are.

[DeepFrz]

The recommendations are to always vent the battery box. Hydrogen gas is explosive and hydrogen sulphide is caustic. How much do you need to breath to cause damage? I don't know the answer to that but its certainly best to vent the gas from the enclosed battery box to an exhaust outlet with a blower fan. So, using a blower fan to vent the battery box means the box should be sealed.

Your instructor was not just blowing gas...

[msponer]

Have you guys ever heard of a hydrogen explosion on a boat? It's the lightest, fastest thing in air-- its hard to imagine bubbling batteries making 4% of the volume of even a small compartment unless its completely sealed.

By the way, I've only ever smelled sulfur when charging old, half dead, batteries.

[btrayfors]

Never heard of an explosion. Deleterious effects on health would be VERY hard to prove in the real world, but that doesn't mean they don't exist.

One thing for sure: flooded batteries under charge DO emit fumes.

WaterMiser caps can go a long way toward reducing the loss of electrolyte and reduce the need for watering. I've used them on my boat for many years, with batteries inside the cabin, and have had no ill effects.

A good source for them is Northern Arizona Wind and Sun....about $4.80 each and well worth it IMHO.

Bill