Carbon Monoxide Detectors

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Jun 11, 2004
15
Hunter 33 San Antonio
Folks, I received a call from one of my dock mates that my boat had an alarm going off continuously, upon investigation, I discovered that my Carbon Monoxide detectors were going off. I tried unsuccessfully to reset them via the reset buttons on the detectors themselves. I finally disconnected them at the DC panel. My boat had been resting at the dock for over a week, without the engine having been run, or any cooking going on.  Any thoughts on why they would go off? Any thoughts on why I couldn't reset them at the detector, the documentation says holding down the reset button for 3 secs will reset?
 
Feb 10, 2004
4,232
Hunter 40.5 Warwick, RI
There are a variety of reasons......

If your boat was un-attended, the most likely cause for the CO alarm is battery charging. A vented wet cell that is being charged gives off vapors the the CO detector detects. If your boat was plugged in and charging and also closed up, this could be the cause. Additionally, there is a laundry list of other causes for a CO alarm that have nothing to do with carbon monoxide. Kidde used to have a list of these causes on their website- you might look there for further info. EDITED to add: I looked and could not find a list of causes. However, my recollection is that solvents, paints, ammonia, and other 'common' household cleaners may cause an alarm. Regarding the 3 second reset- if the detected level is great enough, they won't reset in my experience. Another less likely cause for the alarm would be a neighboring boat that was putting out exhaust and having that exhaust finding a way into your boat.
 
Dec 14, 2003
1,450
Hunter 34 Lake of Two Mountains, QC, Can
Carbon monoxyde level still too high.

As Rich says, if they don't reset chances are the level is too high for them to reset. Since you cannot smell carbon monoxyde, most people just think the detector is faulty. That could be a deadly mistake. Another reason, particularly if the detectors are old, could be arcing of the contacts created by high humidity. I would suggest you have them checked. And make sure you have good ventilation in the boat when you do all this checking. You don't tell us what type of combustible you use for cooking. You might might have a propane leak, which of course would find its way to the bilge area. Good luck and keep us posted
 
Mar 20, 2004
1,753
Hunter 356 and 216 Portland, ME
CO detector age

You should also check the age of your detectors-if you read the fine print, they're only expected to last 3-5 years in the marine environment
 
Jun 11, 2004
15
Hunter 33 San Antonio
Found it....New problem....

Ok, I found out that for some reason, my starter battery got fried, and the gas that was making the alarms go off was cause by the fumes from that battery. So, now I need to figure out why that happened, and buy a new battery. Thanks for all the help.
 
Dec 25, 2000
6,051
Hunter Passage 42 Shelter Bay, WA
Everett, based on your most recent reply...

did your battery boil dry? If so then you need to replace it. One of our 8D batteries did the same thing. The Interstate battery guy told me that a short in one of the cells was the culprit. I estimate their the age at seven years. Terry
 
Feb 10, 2004
4,232
Hunter 40.5 Warwick, RI
The victim was your battery, but the killer may...

..be the battery charger. I had a Guest 30A charger (a total POC IMO) connected to a house bank that was 450Ah. It turned out that the Guest charge never went into float mode because that mode was triggered by a charging current of less than 4A. The normal charging current of my large bank was 5A+, so the result was that my bank was subjected to a higher charging voltage (and current) than it would have been in a float mode. The batteries boiled nearly dry and I'm sure I shortened the life considerably with this mishap. If your starting battery is connected with your house bank you may have an equivalent situation. OTOH, if your battery was old, it may have just developed a shorted cell.
 
Jun 11, 2004
15
Hunter 33 San Antonio
Battery Boiled Dry....

Yes, the battery boiled dry. My boat is 2004 Hunter 33,and this was the original starting battery, so my guess is the battery is only 2-3 years old. How do I check the charging amps? I will not get out to the boat again until this weekend. Thanks again, for all the help.
 
Feb 10, 2004
4,232
Hunter 40.5 Warwick, RI
OK, here's the scoop....

First, you obviously need a new battery. Procure and install. Turn OFF all your DC loads on the boat- lights, refridgeration, etc. Then turn on your charger. You didn't say what brand or features that your charger has, but if it has an ammeter or at least some LEDs to indicate what it is doing, see what the charging current is. With a brand new fresh battery, I would expect that the charging current would be about 5-10A for no more than an hour, then it would drop to about 1-2A. If your charger has LEDs, it should show "bulk" or normal charging for the same hour and then should show an indication of "ready", "float", "complete", or something similiar that indicates that the battery is pretty much fully charged. If the charger is truly DUMB, then you need an ampmeter to place in series with one of the leads of the battery. Many hand-held multimeters have a 10A or 20A scale that can be used. This is something that you should have onboard (IMO) anyway. Measure the charging current after the system has settled out and is no longer decreasing. I would expect a reading of under 2A. Now turn off the charger. Connect an ampmeter in series with the battery if you haven't already done so. Then, turn on the refridgerator and lights. I know that you said the battery was a starting battery, but there could be a mis-wire such that the starting battery is somehow connected to your house bank. If the current does not increase from nearly zero, then the battery is not connected into your house circuits. That would be correct. Now turn off the refridgerator and lights. Turn the charger back on and you may see a small jump in the charging current for 5-10 minutes. Then turn on the refridgerator and lights with the charger turned on. HERE IS THE KEY: If the charging current on the starting battery increases when the DC house loads are turned on, then the charger that is charging the house bank is providing a "mirror" charge to your starting battery. IMO this is not real good. The reason is that when your boat is at the dock with power on and the charger is running, everytime the refridgerator kicks on, the charger will increase it's output to supply that power to the house bank AND at the same time it will increase the charging current to the starting battery. But since the starting battery doesn't need charging, this "excess" charge will serve only to boil off the battery. How to fix? I would not leave the power plugged in when you are not aboard. I know this means having a warm refridgerator, but it eliminates several possible problems. First is the overcharge of the starting battery, and second is the potential for electrolysis issues with your underwater metal. The boiled battery is the least of the issues. Another fix would be to disconnect the charger from the starting battery. For a battery in good condition and no continueous loads, there is no need for a charger to always top-off the starting battery. The engine will do this when it is run, just like your car. Then you can have your cold beer and you only have to worry about the electroylsis. <grin> Sorry this is kind of long, but I thought it might be useful to you.
 
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