Sulphur smell from battery. Dangerous?

[Tigerr]

One of the 4 batts is hot and giving off hydrogen sulphide. Started to notice it strongly after a few hours cruising and charging today. Now stopped. Question is, safe to use 12v electrics? Obvs needs new batt but will have to travel a couple of hours. Best course of action?

[Guest]

Just now, Tigerr said:

One of the 4 batts is hot and giving off hydrogen sulphide. Started to notice it strongly after a few hours cruising and charging today. Now stopped. Question is, safe to use 12v electrics? Obvs needs new batt but will have to travel a couple of hours. Best course of action?

 

Disconnect the one that is smoking.

 

Once had this and managed to remove it from the bank I reckon just before it went pop.

 

I then went on to replace them all as they were all the same age.

 

[Tony Brooks]

Wot he said ^^^^^^^.

[Guest]

 

PS important make sure the gassing has cleared and it's off charge when you disconnect.

[Cheshire cat]

I found that the hydrogen sulphide gas attacked anything with copper in it. You might want to rinse everything nearby down once the offending battery is removed. I removed my dodgy one and left it on the bank overnight to cool down. The remaining ones worked fine for a few weeks until I could replace the whole bank.

[GUMPY]

If you leave it on charge it will go bang😱

[jonesthenuke]

Disconnect  the hot/ smelly battery immediately. Its probably got a shorted cell and the other batteries will continue to feed current into it until its removed.

Also ensure plenty of ventilation, the hydrogen sulphide is poisonous if in a high concentration.

[Wanderer Vagabond]

39 minutes ago, Tigerr said:

One of the 4 batts is hot and giving off hydrogen sulphide. Started to notice it strongly after a few hours cruising and charging today. Now stopped. Question is, safe to use 12v electrics? Obvs needs new batt but will have to travel a couple of hours. Best course of action?

Agree with the other posters, take the defective battery out of the bank since if it does short it will probably finish off your other batteries as well. Bear in mind that H2S is flammable so any sparks could ruin your day. Just out of curiosity, do you have any CO detectors on your boat? When one of our batteries began gassing back in September it set off both CO detectors at the other end of the boat.

[mrsmelly]

Please be careful when you disconnect it!! Put at least eye protection on. We had one explode at work and if anyones face had been near it when it went off it could have been disastrous, the heavy case exploded like a hand grenade.

21 minutes ago, GUMPY said:

If you leave it on charge it will go bang😱

On occasion a bloody big bang!!

[Slim]

53 minutes ago, Wanderer Vagabond said:

Bear in mind that H2S is flammable

Obviously what everyone else said but I thought that HS2 was a damp squib.😇

[NB Alnwick]

1 hour ago, Cheshire cat said:

I found that the hydrogen sulphide gas attacked anything with copper in it.

We once left our boat on charge from a mains hook-up. When we returned one of the batteries had failed exactly as described and all the brass and copper throughout the boat had turned black! And it isn't easy to clean it off!

These days, we disconnect the batteries if the boat is unattended and check battery health regularly.

It is obviously essential to disconnect and isolate a faulty battery immediately.

Edited November 8, 2023 by NB Alnwick

[Guest]

31 minutes ago, NB Alnwick said:

We once left our boat on charge from a mains hook-up. When we returned one of the batteries had failed exactly as described and all the brass and copper throughout the boat had turned black! And it isn't easy to clean it off!

These days, we disconnect the batteries if the boat is unattended and check battery health regularly.

It is obviously essential to disconnect and isolate a faulty battery immediately.

 

We used to leave our boat with the charger on which is which is actually what alerted us to the issue. We'd been cruising several hours and had moored the boat and as usual we flicked the combi on to charge and it immediately tripped off, tried again and exactly the same. Checked what the error light sequence meant and it came up with 'battery over heat'.

 

When I investigated it was obviously correct!!

 

The thing was that out of the six batteries we had in the bank the overheat sensor happened to be on the sole battery that was overheating, if it had been one of the other five we likely would have been oblivious and left the bank on charge as usual.

 

 

Edited November 8, 2023 by M_JG

[The Black Jack]

1 hour ago, Wanderer Vagabond said:

Agree with the other posters, take the defective battery out of the bank since if it does short it will probably finish off your other batteries as well. Bear in mind that H2S is flammable so any sparks could ruin your day. Just out of curiosity, do you have any CO detectors on your boat? When one of our batteries began gassing back in September it set off both CO detectors at the other end of the boat.

We had carbon monoxide detectors go off in the middle of the night on a hire boat. We did all the usual by opening windows, getting out, phoning hire company etc. We were told that because we had it plugged in on a shore line (moored in a marina), it got triggered by hydrogen from the batteries. Will CO detectors really be set off by hydrogen? Surely it vents quickly away?

[Wanderer Vagabond]

14 minutes ago, Mike A R Powell said:

We had carbon monoxide detectors go off in the middle of the night on a hire boat. We did all the usual by opening windows, getting out, phoning hire company etc. We were told that because we had it plugged in on a shore line (moored in a marina), it got triggered by hydrogen from the batteries. Will CO detectors really be set off by hydrogen? Surely it vents quickly away?

I don't think hydrogen would set off CO detector unless in a very enclosed space since if hydrogen gets released it rises. Hydrogen Sulphide however is denser that air (slightly) so will percolate throughout the boat, so it probably wasn't hydrogen that triggered your detectors, but H2S, the same as triggered ours.

Edited November 8, 2023 by Wanderer Vagabond

[The Black Jack]

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

[bizzard]

Very rapid charging doesn't help.

[Wanderer Vagabond]

Just now, Mike A R Powell said:

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

Depends, where is the fan going to blow the fumes unless you have a hole in your hull somewhere? I've thought about that as a means of trying to cool my alternators, but ultimately all you are doing is circulating air around the engine compartment.

 

[ditchcrawler]

4 minutes ago, Mike A R Powell said:

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

That way you can keep blowing the gasses away until the batteries explode, and they do.

[cuthound]

2 minutes ago, Mike A R Powell said:

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

 

Usually. It is caused by batteries being over charged. Old batteries develop short circuits, usually because of a build up of active plate material, which drops of the plates and builds up at the bottom of the cell, shorting put one cell. This increases the charge on the remaining cells.

[Guest]

5 minutes ago, Mike A R Powell said:

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

 

A fan system is unlikely to prevent a battery with an internal short self destructing.

[The Black Jack]

2 minutes ago, Wanderer Vagabond said:

Depends, where is the fan going to blow the fumes unless you have a hole in your hull somewhere? I've thought about that as a means of trying to cool my alternators, but ultimately all you are doing is circulating air around the engine compartment.

 

Perhaps a pipe leading upwards and through the deck boards? Not much different to venting smells from a composting toilet I'd have thought.

[Guest]

Just now, Mike A R Powell said:

Perhaps a pipe leading upwards and through the deck boards? Not much different to venting smells from a composting toilet I'd have thought.

 

The smell isnt really the biggest problem though.

[Tracy D'arth]

Having had batteries split, explode and on one occasion actually set on fire I would say Don't mess with smelling batteries, get them out of the boat ASAP.

[Alan de Enfield]

33 minutes ago, Mike A R Powell said:

Are aging batteries to blame then? Sounds like a fan in the engine bay might be a good idea.

 

We have 2x 'bilge blowers' that suck fumes out of the engine room, up pipes, and out of the deck.  They are used for prior clearing of the bilges before starting the engines - They could be used to clear the battery gases, but they would not stop a battery exploding.

[system 4-50]

I'm not keen on the smell of hydrogen sulphide.  Does anybody do batteries that give off a different smell when they fail?   Lavender would be nice.