CO detectors sounding alarm

[405driver]

I have a 405 and the boat is new to us...about four months. A few weeks ago one of our marina neighbors called to say that an alarm was going off in our boat. I drove over and found two of the CO detectors sounding an alarm loud and clear. When I opened the windows in the boat, the alarms eventually quit. I was about to put new detectors in anyway, finished that task today. I had to go to the marina tonight to pick up some clothes and the new detectors were sounding again.

Now, there is nothing running on the boat except the refrigerator and the battery charger. Tonight I have read on line that a CO detector can also detect hydrogen. If that's true, seems that the only thing it could be is the battery system. Perhaps the battery charger is over charging, or there is a bad battery. Funny thing is, it seems to only happen at night.

Has anybody else had this issue and what was the fix?

Thanks for any opinions.

[tomschauer]

The CO detectors will alarm with Co of course, also low voltage will send them into alarm. If you were cooking a battery enough to set off the alarm I believe you would be able to smell a Sulphur type smell very readily when you entered the boat.
I would check a couple things, are you losing shore power intermittently and draining the batteries with the fridge? Check the clock on your micro wave or something similar, is it flashing when you get there (power loss)? Is the neighbor running their genny when the power drops and actually sending CO into your boat? Maybe your battery charger is failing and cutting in / out. the CO detectors are 12v hard wire or should be. Try adding a self contained battery co detector and see if it alarms also.

Just a few ideas.

[Midnight Sun]

I would bring a home style co unit on board with digital readout so you have something to compare to.

[bud37]

I had the same sort of thing but turned out it was a voltage thing, switched battery feed and alarm stopped. Now that said bringing a portable on board is a great idea and I will throw something out there that the night thing could be air being warmer inside and creating air convection pulling the H2 ( lighter than air ) from the batteries inside.
Interfering gases of similar molecular size and chemical reactivity may produce false positive response. Major interferents that can affect CO detectors are acetylene, dimethyl sulfide, ethyl alcohol, ethylene, hydrogen cyanide, hydrogen sulfide, isopropyl alcohol, mercaptan, methyl alcohol, propane, nitrogen dioxide, and sulfur dioxide.This is from a firefighters site.
Try leaving the boat with the battery charger off with no other change..........

[waybomb]

I had the same thing on my Riviera (2807 Carver).

Turns out, the battery charger was overcharging the batteries, and the CO detector was sensing the battery gas as CO.

Odd, but it happened. Had to drive all the way from Bakersfield to Ventura in the middle of the week because of it.

Check you charging voltage and water level.

[405driver]

Thanks....I think that's exactly it. It's the only thing that makes sense with everything on the boat shut off. Last night we shut off all the power to the boat and opened all of windows...the alarms stopped. That means that the battery charger was shut off and the boat flooded with fresh air.

On my way now to check the batteries and the charger....

Thanks.....

[Viper]

CO detectors are prone to false warnings with age....they don't last forever and many have expiry or manufacture dates on them for replacement reference. Most nuisance tripping is generally due to low voltage either from the source/supply or because of a poor connection.

[Midnight Sun]

Source of the post CO detectors are prone to false warnings with age....they don't last forever and many have expiry or manufacture dates on them for replacement reference. Most nuisance tripping is generally due to low voltage either from the source/supply or because of a poor connection.

He did say the alarms cleared when the windows were opened.

Not sure what they had in Carvers prior to 2007 but mine has Xintex units. Oddly enough they have no advertised life span yet the newer models start screeching after 5 years to tell you it's time. This brings up a point to check the dates on these things when buying new otherwise you unit may only last a year! Below is a link to the new self destructing units. I have not replaced mine yet however I am much less concerned as my boat is diesel.

http://www.fireboy-xintex.com/marine-ca ... d-of-life/

[Viper]

Source of the post CO detectors are prone to false warnings with age....they don't last forever and many have expiry or manufacture dates on them for replacement reference. Most nuisance tripping is generally due to low voltage either from the source/supply or because of a poor connection.

He did say the alarms cleared when the windows were opened....

Yep. For the benefit of everyone, the statement is meant to advise reasons why they may sound off without the presence of CO.

....I have not replaced mine yet however I am much less concerned as my boat is diesel....

Curious, why do you feel it is less of a concern with diesels? They still produce CO.

[Midnight Sun]

Mostly because diesels give off so little CO ( .05% vs 7%+) Plus the fact that according to ABYC A-24, CO detectors are required only on gas powered boats and therefor assume they would recommend it even if the dangers were slight for diesels.

According to the American Boat and Yacht Council (ABYC A-24) Standards and Technical Information for Small Craft, a carbon monoxide detector must be installed on all boats with an enclosed accommodation compartment and a gasoline generator set or inboard gasoline propulsion engine.

That being said I did say I was less concerned. What does concern me most would be rafting up to someone with a gas generator operating or being close to someone with a gas engine running for extended periods.