Jump to content

Carbon Monoxide – False Alarm, Or Not ?


Alan de Enfield

Featured Posts

Carbon Monoxide – False Alarm ?

Currently moored on the Trent and decided to take advantage of the electricity bollard as we hope to be here for a ‘day or three’ chilling out.

Immersion heater plugged in and on the timer

Battery charger ‘on’

Microwave plugged in

Electric kettle, toaster and ‘George Forman’ all out and ready for ‘duty’

 

2:00 am this morning we are woken to an insistent bleeping of the Carbon-Monoxide alarm (first time ever !!)

Quick check around the boat, gas cooker ‘off’, gas hob ‘off’, Eberspacher heating ‘off’, engines ‘off’

Can find no reason for the alarm.

Reset alarm, goes off again

Reset alarm, goes off again

Open windows and hatches and ‘waft’ towels about

Alarm ‘clicks’ and resets itself – silence.

Have another check around the boat but can find nothing that is likely to be a source of Carbon monoxide  (maybe it was the dog’s ‘wind’)

 

Back into bed but unable to sleep then remember that I read (on this very forum) that battery charging can / may produce a gas which fools the alarm into believing that there is CO present.

Switched off battery charger.

Quiet night and no more alarms.

 

This morning   have checked the batteries water levels – the two starboard side ones were quite ‘dry’ (levels below the plates) but the two central and two Port side were OK (Port side a little low but above the plates).

Topped up all batteries – the ‘dry ones’ took 2.5-3.0 litres between them (2 x 230Ah – big things)

 

Questions  -

Can a CO alarm be set off by battery charging gas ?

Would a ‘dry’ battery produce a gas whilst a ‘filled’ battery did not ?

Why has it never gone off before ?

 

Anyone experienced mysterious ‘false alarms’ with their CO alarm ?

Link to comment
Share on other sites

CO alarms detect certain fuel gasses including CO and H2 (hydrogen).   A gassing battery will generate hydrogen, more so if the charger voltage is high or if there is a duff cell.  So if your batteries are losing water, then the loss is the conversion of water into hydrogen.  This hydrogen which vents from the batteries then rises up and flows along the roof to the vents.

 

added - Being pedantic, this was probably not a false alarm as the detector was working correctly and detecting a fuel gas.  It would be better to call it a false positive.  Moving the alarm away from the batteries, or a bit lower down, but located in a place compliant with the manufacture’s recommendation may help by avoiding the H2.  It may also be worth while investigating the charging voltage. Where you doing an equalising charge at the time?

Edited by Chewbacka
Link to comment
Share on other sites

9 minutes ago, Alan de Enfield said:

Carbon Monoxide – False Alarm ?

Currently moored on the Trent and decided to take advantage of the electricity bollard as we hope to be here for a ‘day or three’ chilling out.

Immersion heater plugged in and on the timer

Battery charger ‘on’

Microwave plugged in

Electric kettle, toaster and ‘George Forman’ all out and ready for ‘duty’

 

2:00 am this morning we are woken to an insistent bleeping of the Carbon-Monoxide alarm (first time ever !!)

Quick check around the boat, gas cooker ‘off’, gas hob ‘off’, Eberspacher heating ‘off’, engines ‘off’

Can find no reason for the alarm.

Reset alarm, goes off again

Reset alarm, goes off again

Open windows and hatches and ‘waft’ towels about

Alarm ‘clicks’ and resets itself – silence.

Have another check around the boat but can find nothing that is likely to be a source of Carbon monoxide  (maybe it was the dog’s ‘wind’)

 

Back into bed but unable to sleep then remember that I read (on this very forum) that battery charging can / may produce a gas which fools the alarm into believing that there is CO present.

Switched off battery charger.

Quiet night and no more alarms.

 

This morning   have checked the batteries water levels – the two starboard side ones were quite ‘dry’ (levels below the plates) but the two central and two Port side were OK (Port side a little low but above the plates).

Topped up all batteries – the ‘dry ones’ took 2.5-3.0 litres between them (2 x 230Ah – big things)

 

Questions  -

Can a CO alarm be set off by battery charging gas ?

Would a ‘dry’ battery produce a gas whilst a ‘filled’ battery did not ?

Why has it never gone off before ?

 

Anyone experienced mysterious ‘false alarms’ with their CO alarm ?

Batteries do produce CO when charging ,have noticed this when trying to coax a Battery back to life when Bench Charging.

Link to comment
Share on other sites

2 minutes ago, cereal tiller said:

Batteries do produce CO when charging ,have noticed this when trying to coax a Battery back to life when Bench Charging.

I don't think that is actually true but it is well known that other gasses produced when charging, especially at high voltages or faulty cells are detected as CO by CO meters - as others have said.

I can't see where the carbon atom would come from during charging to form CO

  • Greenie 1
Link to comment
Share on other sites

Yes, it is hydrogen from the charging process that sets them off.  It is well documented that CO monitors are also very good at detecting Hydrogen.

Flamingo's batteries are actually in the engine room, physically separate from the main accommodation space, and with only a few smallish holes in the bulkhead interconnecting the two.

It is hard to imagine enough hydrogen can get through those holes, and 12 feet further on into the cabin to set off the alarm but it did.

On the occasion we had it, only one battery out of 5 was gassing badly, but feeling that battery revealed it to be very hot, whereas the remaining 4 were not.  Having heard just how much damage an "exploding" battery could do, and not wishing to think about what would happen if sulphuric acid ended up under the immoveable fuel tanks, such that I couldn't clear it up, we immediately took that battery out of service.

If you have some batteries where the level was not heavily depleted, and some where it was, I would be tempted to think the latter are probably not long for this world.

If any are getting very hot when charged, I think I'd consider taking them out.

 

Link to comment
Share on other sites

1 hour ago, Alan de Enfield said:

This morning   have checked the batteries water levels – the two starboard side ones were quite ‘dry’ (levels below the plates) but the two central and two Port side were OK (Port side a little low but above the plates).

Topped up all batteries – the ‘dry ones’ took 2.5-3.0 litres between them (2 x 230Ah – big things)

 

Would a ‘dry’ battery produce a gas whilst a ‘filled’ battery did not ?

As others have said CO monitors can react to hydrogen.

I would keep an eye on the two cells you had to top up. It is possible that these cells have internal shorts, which will cause them to gas more, generating more hydrogen to set of the CO monitors and boiling away the electrolyte when on charge.

If they have shorts, your overall battery capacity be reduced, so the lights will go dim quicker as well as the electrolyte boiling off. They will also gas more vigorously than the cells without shorts when charged.

Link to comment
Share on other sites

3 minutes ago, Alan de Enfield said:

 

It was two batteries out of the bank of 6 (rather than 2 cells)

The other 4 batteries are quite a bit 'younger' so maybe these two are nearing the end of their life.

Whether they are cells (2 volt batteries) or 12 volt batteries makes no difference, sounds like they have shorts. 

With them being older makes it more likely. One reason why some people don't recommend mixing batteries of different ages.

Personally I think it is ok to mix different ages of batteris as long as you KEEP AN EYE ON THEM.

If they do have shorts, change them ASAP. Batteries with shorts can explode, and clearing up is messy.

Link to comment
Share on other sites

My shorts never exploded. Chilly time of year for wearing them though. Spontaneous combustion, setting people alight has been known, caused by passing wind whilst wearing nylon underware. :closedeyes:

Edited by bizzard
  • Greenie 2
Link to comment
Share on other sites

Definitely battery gasses, with our ageing Trojans situated in the engine room our Co alarm in the back cabin has been triggered many times, always at the same point in the charging cycle. I wonder if your immersion issue the other day gave the batteries a work out? 

Link to comment
Share on other sites

38 minutes ago, Alan de Enfield said:

 

It was two batteries out of the bank of 6 (rather than 2 cells)

The other 4 batteries are quite a bit 'younger' so maybe these two are nearing the end of their life.

Just to clarify, if one cell in a 12v battery has an internal short, it means the remaining 5 cells now have a much greater charging voltage across them than they should, and so gas freely. So a shorted cell will show up as a general loss of water in that battery, not just in the one cell.

Link to comment
Share on other sites

1 hour ago, Peter X said:

If I was on a boat where hydrogen was accumulating, I think I'd want it detected. Remember the Hindenberg?

Light the gas hob in the morning, could go Kaboom!?

I have only seen the aftermath of one battery explosion, and one was enough.

An unsupervised decorating contractor placed some polythene sheeting over a 50 volt battery bank (comprising 25 x 2 volt batteries) whilst he was decorating.

When he removed the sheeting a spark, presumably caused by static electricity ignited the two 2 volt cells on the other end of the battery to where he was pulling from.

Luckily he wasn't injured, but the acid permanently stained the vinyl flooring and flying glass took chunks out of the solid concrete walls and ceiling.

Oh,  and he had to redecorate again after the mess was cleaned up. 

Link to comment
Share on other sites

1 hour ago, Peter X said:

If I was on a boat where hydrogen was accumulating, I think I'd want it detected. Remember the Hindenberg?

Light the gas hob in the morning, could go Kaboom!?

As Hydrogen is 'lighter than air' I don't forsee any problem with it collecting in the bilges - it will happily float up out of the engine room and out of the vents & windows.

Not being complacent, just cannot see a 'kaboom' happening.

Link to comment
Share on other sites

6 minutes ago, Alan de Enfield said:

As Hydrogen is 'lighter than air' I don't forsee any problem with it collecting in the bilges - it will happily float up out of the engine room and out of the vents & windows.

Not being complacent, just cannot see a 'kaboom' happening.

And the last time we discussed this, one of the experts on here pointed out that the alarm alarms at H2 concentrations well below ignition levels. Still need to weed out those two batteries though.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.