# Battery charging sets off carbon monoxide detector



## heruide (Feb 12, 2008)

​Over the last year there were times when my home carbon monoxide detector (CO) would go nuts when I was charging my PUP battery. Typically it would happen late at night. The first couple times I was really concerned that I had a CO problem, but with no combustion source active at the time I finally figured it was related to the battery charging. 

However, batteries lead acid batteries will emit hydrogen so why was the CO detector going off? Rather than do some research I just made a mental note “CO detector goes off while battery is being charged… not to worry. But if detector goes off and I’m not charging the battery… I need to investigate and find the source quickly or exit the house.”

On Saturday evening I came home only to hear the CO detector wailing as I’ve never heard it before. To make a long story short, I had been charging the battery in the garage and I left the door to the utility room ajar. The kitchen CO detector took exception to this and was letting me know in no uncertain terms that it was not happy. The catch was the battery was already charged but the damage was done.

DW was upset and opened almost every window in the house. The good news is that the outside temperature was 71 degrees and airing out the house was a good idea anyway.

So I decided I would at least confirm that hydrogen gas was known to interfere with CO detectors. Yep… thanks to the internet not only did I read where several folks had pondered this question but several fire departments had responding to CO alarm calls and it took them some time to figure out what the problem.

One of the things I learned from reading fire fighting training material was that in addition to battery charging and hydrogen gas there are lots of common household chemicals and substances that may have an effect on the CO sensor. They are: 

Aerosols – (hair sprays, deodorizers, Lysol, etc…)
Cleaning supplies – (Clorox, Bleaches, etc…)
Gas from charging batteries
Paints
Stripping chemicals
Varnish
Silicon glue or compounds
Alcohol
Methane
Toluene
Acetone
Nail polish
Nail polish remover
Sulfur compounds
Sewer gas
Vapors from baby diapers
Car exhaust fumes
Cigarette smoke
Incense smoke
Ammonia
Carpet cleaning solutions
Sealant
Freon from air conditioners
Hydrogen
Nitroglycerin (usually from heart medication)

NOTE, I hesitated to publish the list above since some of the items do contain CO and I do not want to give the impression that there are so many substances that interfere with a CO detector that one should not have one.

The other concern I had was whether the hydrogen level was high enough to create an explosive environment. I was relieved to read of a case where the fire department “Using a cross-sensitivity table supplier by the CO sensor manufacture showed that 80 ppm on the CO sensor means that there was approximately 200 ppm of hydrogen present. This is well below hydrogen Lower Explosive Limit (LEL) of 4 percent (40,000ppm)” Note my CO monitor was reading 89 ppm when I entered my home.

Ruide


----------



## happiestcamper (Mar 6, 2008)

Have personally experienced Lysol and paint setting it off. We also had a scare one night when it went off, and the fire department ruled that the 5 year old monitor was now defective. Wish it hadn't decided to go defective at midnight :thumbdown:


----------



## heruide (Feb 12, 2008)

LOL I understand some of these devices have very poor timing.

One of the things I need to do is check and see what the recommended frequency is for replacing the CO detector. Apparently some companies recommend replacing them every 5 years.

Ruide


----------

