Co Alarm, False Alarms

[PaulRainbow]

I have a Co alarm fitted just below the ceiling in my aft cabin, it's fitted there as it's the closest area to where the Eberspacher lives and the cabin that i sleep in. At random times the alarm goes off, during the day. The last few times there has been no heating or cooking appliances on and none of the adjacent boats have been occupied. It might go off twice in two days, it might be twice in three weeks, totally random.

I've emailed the manufacturer, who have said they would test it and replace if faulty, but they say false alarms are "very unusual", although in later emails they say

we have had quite a few cases ( in boats and caravans) where there has been a fault with the leisure battery ( leaking hydrogen) - the hydrogen can then contaminate the internal sensor of the alarm , causing activation. This is most likely to happen during the night , as the moment of people within the living space during the day is causing a constant movement of air – which in turn will dilute the hydrogen that has escaped.

I have four batteries, charged by solar panels, under one of the saloon sofas. Seems to me if batteries being charged in an adjacent cabin are going to keep setting the alarm off it isn't much use on a boat.

Anyone else had this issue ?

 

[GHA]

Mains charging at absorption of 14.8v (trojans) will set my alarm off after a while, in the same cabin a the batts. Not enough oomph from the solar to set it off.

Not a fault with the co alarm, it shows something like 180ppm.

 

[prv]

Anyone else had this issue ?

I've had acetone fumes set the LPG detector off, but my CO detector has been well-behaved so far...

Pete

 

[VicS]

I've had acetone fumes set the LPG detector off, but my CO detector has been well-behaved so far...

Pete

The LPG detector is basically a flammable gas detector. Almost any flammable gases or vapours are likely to trigger it. The only "special" thing about it as an LPG detector is the concentration of gas (10% LEL ???) it is calibrated to alarm at. I guess CO would set it it off but at a very high concentration compared with the level we are normally interested in for CO.

CO detectors are I believe electrochemical cells and somewhat more specific but not immune from cross sensitivity. Hydrogen is one of the gases to which they are sensitive. Hydrogen sulphide is another

I believe that for critical industrial use substance specific detectors are available but they are not what you find in your domestic CO alarms.

 

[mlines]

How old is the alarm

CO alarms have a "life" - 7 to 10 years. Some then have an "end of life" alarm to tell you they need replacing others (typically older ones) do not.

We had an older one and it started to randomly alerting, more and more frequently. We then bought a cheap battery one that had a display of the CO levels as well. Put it alongside the old one and could see when the old one alarmed that the levels on the new one were fine.

Martin

 

[bitbaltic]

I have a Co alarm fitted just below the ceiling in my aft cabin, it's fitted there as it's the closest area to where the Eberspacher lives and the cabin that i sleep in. At random times the alarm goes off, during the day. The last few times there has been no heating or cooking appliances on and none of the adjacent boats have been occupied. It might go off twice in two days, it might be twice in three weeks, totally random.

I've emailed the manufacturer, who have said they would test it and replace if faulty, but they say false alarms are "very unusual", although in later emails they say

I have four batteries, charged by solar panels, under one of the saloon sofas. Seems to me if batteries being charged in an adjacent cabin are going to keep setting the alarm off it isn't much use on a boat.

Anyone else had this issue ?

I've had a CO alarm triggered by a gassing battery in just the manner you describe. The important point is that most batteries when charging normally won't leak out hydrogen (can't speak for all of them as GHA seems to regard his gassing trojans as normal) - the issue is, as your alarm manufacturer has said, when you have a faulty battery. My leisure battery was old and had been finished off by a total discharge event (left the fridge on and shorepower off) - replaced it with a nice new Rolls and there have not been any false alarms since.

Assuming the alarm is in-date (as per mlines point above) then one or more of your batteries needs looking at, not the CO alarm. Suspect the "randomness" is related to variation in sunshine hours and thus the juice supplied by your solar charging system.

 

[GHA]

(can't speak for all of them as GHA seems to regard his gassing trojans as normal)

Not me thinking it's normal, manufacturers recommended absorption voltage. On solar without the luxury of leaving a mains charger connected all night, if you're not getting at least a tiny bit of gas (obviously not with sealed like agm) then chances are your batteries won't be getting to full charge.

http://www.cruisersforum.com/forums...tor-bulk-charge-issue-179406.html#post2389968

 

[macd]

Not me thinking it's normal, manufacturers recommended absorption voltage. On solar without the luxury of leaving a mains charger connected all night, if you're not getting at least a tiny bit of gas then chances are your batteries won't be getting to full charge.

...and will be at increased risk of stratification and sulphation. Gassing is normal for well-regulated flooded batteries.

 

[bitbaltic]

OK, wouldn't claim to be an authority on it. So if gassing batteries are desireable (especially/particularly on solar) then Paul probably has a point about CO alarms being less useful on boats with that setup?

Very glad my battery charges fine without producing sufficent gas to set off my CO alarms!

 

[GHA]

OK, wouldn't claim to be an authority on it. So if gassing batteries are desireable (especially/particularly on solar) then Paul probably has a point about CO alarms being less useful on boats with that setup?

Not if you read...

Mains charging at absorption of 14.8v (trojans) will set my alarm off after a while, in the same cabin a the batts. Not enough oomph from the solar to set it off.

 

[macd]

wouldn't claim to be an authority on it.
Very glad my battery charges fine without producing sufficent gas to set off my CO alarms!

But presumably you can read? Rolls recommend bulk/absorption voltages in excess of 15V for their flooded batteries. Which Rolls battery do you have?

And if you're no authority, do you think a sweeping assertion that a gassing battery is on its last legs is just a little bit irresponsible?

Incidentally, precisely how do you know your battery "charges fine"?

 

[bitbaltic]

But presumably you can read?

Cheers, I think I'll leave you to it if that's your attitude. Apologies if you think I've insulted you in a manner deserving of that sort of put-down. Enjoy your day!

Hope Paul gets his problem sorted whatever the cause is.

 

[macd]

Apologies if you think I've insulted you in a manner deserving of that sort of put-down.

I fear that the only insult will be the one you're perpetrating on your new battery.

 

[PaulRainbow]

Thanks for the replies. The alarm is less than a year old and is a Fire Angel 10yr life one. It went off yesterday lunchtime while the batteries were being charged by solar, as usual, and the main companionway hatch was open, along with three other hatches being very slightly open (again, as usual).

My domestic bank consists of two open cell batteries and one sealed one (don't ask), so i set the mains charger and solar controller for sealed batteries. Bulk/Absorption with the solar controller is 14.4v and it does usually reach this for quite a while each day.

I've just put the mains charger on an equalisation cycle. I've shut the companionway hatch, so will see if this sets the alarm off. It will also give me a good starting point to run some tests on each battery. Might do the same as Martin in #5 and buy a second alarm with a display. Martin, what did you buy ?

 

[PaulRainbow]

Batteries very gently bubbling at 15.3v at the moment, although each of the open cell batteries has a cell that isn't bubbling, don't like the look of that, my wallet is trembling

Co alarm just went off. Opened the hatch in the aft cabin, still going off. Put it in the cockpit, quickly stopped. Will try bringing it back onboard............

Edit : 10 minutes inside the aft cabin and off it went again. Literally 1 minute in the cockpit and it stopped. Almost certainly the batteries setting it off, so i'll have to do some testing and see if i have a dodgy battery or two.

 

[PaulRainbow]

As suspected earlier, i have to knackered batteries. Both of the open cell batteries dropped to about 11v after just three hours. The almost new sealed Numax is holding up fine and must have been running things overnight on its own, although i had noticed that the voltages were dropping lower than normal recently. I've disconnected the offending batteries and have turned the emergency "combine" switch on, so i can run off of the Numax and the engine battery until some new ones arrive next Tuesday. Plan is to fit three Varta A28s, which are wet cell, same as the two knackered ones, which are of unknown vintage (came with the boat). I'll stick the surplus Numax on the for sale forum, it's only 8 months old.