CO Detector also detecting hydrogen?

[first230sl]

Hey there. Every once in a while, the CO detector in the foreward V-berth on our 58YF goes off. Usually at night. Each time I bring another CO detector in to verify - and indeed - both show a reading. It usually seems to be seeping up from the bildge area under the floor as the reading is higher under the hatch. It was always a bit baffling as typically the only source of combustion at the time is our Kabola diesel heater. But the output is far away and there is no reading in the engine room where the Kabola is.

It happened again last night when we were on the boat. This time I wanted to get to the bottom of it. After hunting around (won't bore you with those details), I finally discovered that the "CO" is coming from the batteries. Now - I realize it is not since batteries cannot produce CO. So it seems pretty clear to me that the detectors I have detect hydrogen in addition to CO. BTW - the ambient reading in the battery room was about 50-100, and the reading right above a battery (which was noisly gurgling with visible bubbling as it charged) max out at 999 - the highest displayable reading. If it were CO, I'd not be typing this.

Anyone had this experience?

Seems to me I should consider better evntilation for the battery room - though there is an existing vent. I found a hydrogen detector on line which has a relay to start an exhaust fan at 1%, and then alarms at 2%. If it is not too expensive, I will get one and hook it up to an exhaust fan.

Take care - Murray

[Boss Lady]

Hydrogen is highly explosive. I don't know squat about detectors. However, CO is heavier than O2 and will displace it in a confined space like your boat hull. Distance from the source is immaterial. Just think of water flowing down hill and then filling up your hull, and you will get the picture of how CO accumulates. Neither situation is good. Take immediate action to correct this. You need positive ventilation to get rid of CO.

It doesn't take much Hydrogen to create an explosion. I was blown out a truck cab once while jump starting another vehicle. The truck was an Army 2 1/2 ton truck, the batteries are under the seat, and we had the seat up, the windows down and one door open, but sufficient hydrogen was present to create an air burst that threw me 5 feet backwards when I connected the jumper cables (spark). The cause was low battery level, and they were boiling off hydrogen, you could actually see white looking gas coming out of the vent caps. We topped them off with water and the problem was solved. I learned a valuable lesson that day.

[MikeP]

FIRST, DO NOT IGNORE THE CO ALARM - People have died doing so.

Several years ago there was a newspaper article - a guy on Long island disabled his CO detector and he/his family died from CO poisoning. His neighbors said that he had complained about the constant alarms but he didn't smell or see anything so he disabled it...CO is colorless and odorless!

I have never heard of Hydrogen/Oxygen triggering a CO detector. I'm not saying it can't happen but you need to be very careful to be sure exactly what is going on.

This is not something to fool around with.

[first230sl]

FIRST, DO NOT IGNORE THE CO ALARM - People have died doing so.

No worries - I am completely aware of the dangers - that is why I have 4 detectors on the boat.

And yes - I can assure you it was indeed hydrogen. It took some investigation - but the source was the charging batteries, and that is what they produce. I would never consider disabling a CO alarm. What I did do was to dissipate the hydrogen and everything was fine after that (reading of 0).

And thanks for the anecdote on the volatility of hydrogen gas mixed with oxygen. Glad you were OK. I am aware of the dangers and that is why I am considering concentration-triggered ventilation.

Overall - I am not so foolish as to believe that I can't do something foolish :-) But thanks for all the cautions. Can't have too many of those.

Take care - Murray

[first230sl]

I looked up how CO detectors work. They are based on Platinum Oxide. It reacts (is reduced) by CO to Pt and CO2 - producing heat. This makes the hydrogen theory pretty plausible because hydrogen can also reduce PtO to Pt generating water (and I think heat - but am still checking).

But the fact that both CO and H2 reduce PtO is pretty compelling evidence that a PtO based CO detector will also detect H2. Not certain, but compelling.

Murray

[MikeP]

I was interested in this and did some web research and found that some, if not all CO detectors DO detect Hydrogen, as you suspected. Here's a quote from one of the CO maker's specs:

"This model HIC-203 CO detector will alarm at 2000ppm of Hydrogen, which is 5% of LEL. It will respond to
Hydrogen Sulfide (H2S) and Sulfur Dioxide (SO2) too, but the sensitivity to those gases is relatively low compare
to that of CO."

Of course, then the issue is how do you KNOW for sure that it's detecting H instead of CO?

[Nonchalant1]

Mike,

I have the "CO Experts" monitor and I was recently equalizing charging my batteries and had the same experience. In my case, it's when I opened the generator area trap door after charging all night. It went away within 30 minutes. The hydrogen gas rises, and works it's way out of the boat.

I too am very cautious about hydrogen explosions.... no sparks near the batteries and keep the chargers BELOW the level of the batteries because chargers sometimes have micro-sparks when their internal switches operate.

Now I know why I got that CO reading!

Thanks

[solanderi]

FWIW,

I have two of the CO experts ( http://www.aeromedix.com/product-exe...rts_Model_1070 ) on my Hat. One in the stateroom and the other in the salon. I would say from reading this interesting account that the CO monitor really alerted you to a big time potential problem. What model is it?

The other thing that caught my attention was that the instuctions for mounting the Aeromedix product recommends that you mount it at head level away from doorways and ac vents. That would seem to go against the fact that CO is heavier than air. The only reason I could uncover for mounting the sensors high, is that the CO is a product of combustion and therefore initially lighter than air. (See a discussion at http://www.newton.dep.anl.gov/askasc.../chem03364.htm).

Of note, my CO monitors have only alarmed once and that was backing down on fish. Pretty important stuff, so you want to get it right.

Greg
1985 45C
Hat Time
Miami Beach

[Nonchalant1]

FWIW,

I have two of the CO experts ( http://www.aeromedix.com/product-exe...rts_Model_1070 ) on my Hat. One in the stateroom and the other in the salon. I would say from reading this interesting account that the CO monitor really alerted you to a big time potential problem. What model is it?

The other thing that caught my attention was that the instuctions for mounting the Aeromedix product recommends that you mount it at head level away from doorways and ac vents. That would seem to go against the fact that CO is heavier than air. The only reason I could uncover for mounting the sensors high, is that the CO is a product of combustion and therefore initially lighter than air. (See a discussion at http://www.newton.dep.anl.gov/askasc.../chem03364.htm).

Of note, my CO monitors have only alarmed once and that was backing down on fish. Pretty important stuff, so you want to get it right.

Greg
1985 45C
Hat Time
Miami Beach

Greg,

Mine is a model #2004. It starts warning at 10PPM (maybe too low) and increases it at 25PPM and 50PPM and goes nuts at 75PPM with an Exit Immediately warning. Most govt agencies recommend warning at 25PPM or more.

Doug

[Capt K]

My father's boat (not a Hatt) has some CO detector false alarms in the winter when the boat is closed up. He hears it when he goes in to check on things. This battery vapor idea seems to make sense here, too. The reason is he closes up his engine room vents and shrink wraps the salon window so the boat gets pretty "tight".

Have to look into this and maybe provide more ventilation.

K