Carbon monoxide going off - possible causes?

[westernman]

I have a procharge ultra battery charger, which has different settings for AGM and sealed lead acid (which all my engine room batteries are) - won't it cause issues if I just change the bow thruster battery to AGM?

I would get an ordinary car starter battery. They are designed for delivery lots of amps.
AGM will be more expensive, and I doubt you will see any advantage.
Leisure batteries are a compromise, and have less good CCA specs. They will have high Ah capacities.

There is a lot to be said for having the same kind of batteries everywhere so you don't need separate chargers.

 

[Plum]

That was it! Still pretty warm to the touch, even after several hours without charging - I thought the heads was a bit smelly yesterday, but must have been this.

View attachment 174053View attachment 174054

Any recommendations on a replacement? I guess it needs to be pretty heavy duty given how much umph the bow thruster uses.

I had the same problem of the CO alarm sounding and caused by an old fashioned "2-stage" charger causing gassing but the battery was not faulty or damaged. Fitted a new "smart" charger, problem solved and the battery carried on for another 5 years.

 

[Grumpydev]

I had the same problem of the CO alarm sounding and caused by an old fashioned "2-stage" charger causing gassing but the battery was not faulty or damaged. Fitted a new "smart" charger, problem solved and the battery carried on for another 5 years.

I have a smart charger, I might have salvaged it by topping up the water maybe, but honestly don't want to risk it.

 

[Momac]

Sounds like the existing battery is scrap if it has become very hot.
On reflection Just thinking is probably best to stick with a lead acid battery if there is only the one charger .

 

[Grumpydev]

Just got to find one that will fit back in the box now

 

[penberth3]

Be very careful! And be aware that Hydrogen Sulphide ( H2S ) from a 'cooking' battery will set a CO alarm off.
H2S is an insipid poisonous gas, slight exposure can dull the olfactory nerves so that you don't smell the bad eggs smell after a while. It is also cumulative in your body and toxic.

Is it really H2S from a hot Battery? I always thought it was sulphuric acid vapour. I'm familiar with both smells.

 

[PaulRainbow]

I have a procharge ultra battery charger, which has different settings for AGM and sealed lead acid (which all my engine room batteries are) - won't it cause issues if I just change the bow thruster battery to AGM?

No

 

[PaulRainbow]

Is it really H2S from a hot Battery? I always thought it was sulphuric acid vapour. I'm familiar with both smells.

It's H2 that sets the alarms off.

 

[PaulRainbow]

I would get an ordinary car starter battery. They are designed for delivery lots of amps.
AGM will be more expensive, and I doubt you will see any advantage.

What do you suppose AGM batteries do ?

Leisure batteries are a compromise, and have less good CCA specs. They will have high Ah capacities.

Not true.

There is a lot to be said for having the same kind of batteries everywhere so you don't need separate chargers.

Not true, again.

AGM will be happy enough at 14.4 absorption/bulk and 13.4 float, as will SLA.

Plenty of production boats built with SLA domestic batteries and AGM bow thruster batteries.

 

[Grumpydev]

Thanks, I'll probably go for this:

Advanced LP85 AGM Leisure Battery 85ah 12v | Advanced Battery Supplies

Just need to double check it will fit when I'm next at the boat (as I stupidly didn't measure the box, only the old battery ).

No big deal if we can't run the charger or invertor next weekend, I don't fancy paying postage to post one of these things back

 

[PaulRainbow]

Thanks, I'll probably go for this:

Advanced LP85 AGM Leisure Battery 85ah 12v | Advanced Battery Supplies

Just need to double check it will fit when I'm next at the boat (as I stupidly didn't measure the box, only the old battery ).

No big deal if we can't run the charger or invertor next weekend, I don't fancy paying postage to post one of these things back

In addition to measuring the battery, make sure the posts are the same layout.

Double check the charging profile your charger is set to. Sealed Lead Acid @ 14.4 and 13.6 will be fine.

As long as the battery cables at the bow are insulated to protect them from shorting you can safely use the charger or inverter.

 

[Grumpydev]

In addition to measuring the battery, make sure the posts are the same layout.

Double check the charging profile your charger is set to. Sealed Lead Acid @ 14.4 and 13.6 will be fine.

As long as the battery cables at the bow are insulated to protect them from shorting you can safely use the charger or inverter.

It's currently set to "SLA preset 2", which according to the manual is 14.6 charge, 13.4 float - "SLA preset 1" is 14.4 charge, 13.6 float - do you think its worth changing it to preset 1?

I've wrapped up the cables at the bow, and also switched the isolator off that seems to connect them to the rest of the system (although I've not verified that with a multimeter)

 

[PaulRainbow]

It's currently set to "SLA preset 2", which according to the manual is 14.6 charge, 13.4 float - "SLA preset 1" is 14.4 charge, 13.6 float - do you think its worth changing it to preset 1?

I've wrapped up the cables at the bow, and also switched the isolator off that seems to connect them to the rest of the system (although I've not verified that with a multimeter)

SLA preset 2 will be fine.

 

[vyv_cox]

Is it really H2S from a hot Battery? I always thought it was sulphuric acid vapour. I'm familiar with both smells.

As someone mentioned earlier, it is hydrogen that confuses CO meters and causes them to alarm. I wrote an article on this for one of the mags (YM I think) a couple of years ago. There may well be a smell of H2S, to which the human nose is sensitive to a couple of parts per million but it is H2 that triggers the alarm.

 

[graham]

My co alarm sounded at 5 oclock this morning .Battery charger was on but batteries felt cold and no smell.
(2 sealed lead acid 110 ah each)

My head is directly under the co detector when i am in my usual bunk .Can human breath cause a co detector to sound?

I opened the hatches for a few minutes switched off the charger and got another couple of hours sleep with no further drama.

 

[Grumpydev]

My co alarm sounded at 5 oclock this morning .Battery charger was on but batteries felt cold and no smell.

My head is directly under the co detector when i am in my usual bunk .Can human breath cause a co detector to sound?

I opened the hatches for a few minutes switched off the charger and got another couple of hours sleep with no further drama

Did you check them all? Mine was the bow thruster/windlass battery under the master cabin bed, which I almost forgot about!

 

[graham]

I only have the 2 both were cold and no smell. This happened once before ,last summer so i replaced the detector for this season.

 

[graham]

I just googled and found a report of a paramedic who farted in an ambulance and set off the co detector.could be a possibility I suppose.

 

[Plum]

My co alarm sounded at 5 oclock this morning .Battery charger was on but batteries felt cold and no smell.
(2 sealed lead acid 110 ah each)

My head is directly under the co detector when i am in my usual bunk .Can human breath cause a co detector to sound?

I opened the hatches for a few minutes switched off the charger and got another couple of hours sleep with no further drama.

When I had the same problem the battery charger was definitely the reason but the battery was not warm and continued in service for another 4 years so was not damaged.

 

[wonkywinch]

Had similar problems this week. Marina called to say boat was sounding CO alarm. Put new batteries in but yesterday that device and the main CO/LPG alarm I'd wired in was beeping.

The only thing powered up on shore power is the battery charger. Switched that off and will do some battery testing.