11:50pm - I was just awoke to the sound of some beeping.
Freaking out thinking it was a smoke alarm, I started running around the house. Found it was my CO detector in the shop going off!
And the number on the display was rising!! No fire, no engine running, etc....
Well - the battery in the car had died from sitting for over 3 weeks, so about 8 hours earlier I'd put it on the charger. No, it wasn't on fire!
After being woken up to all this, I did a quick net search and found this:
Carbon Monoxide Detectors and Charging of Lead Acid Batteries
When charging lead acid batteries, hydrogen (H2) gas is produced.
Hydrogen gas is a by-product from the electrolysis reaction (charging)
of the lead acid battery. Hydrogen gas can interfere with the carbon
monoxide detector's sensor. The carbon monoxide sensor is sensitive to
and will respond to hydrogen gas at about a 10 to 15 % of it's actual
concentration. If you find you are getting high carbon monoxide readings
around battery charging operations do not be alarmed, but be cautious.
The Lower Explosive Limit (LEL) for hydrogen is 4.0 % by volume (40,000
ppm by volume). If your carbon monoxide detector alerts, and you are
charging a lead acid battery in the area, disconnect the battery charger
and ventilate the space in order to dissipate the gas.
The public should be aware of the limitations and interferences that
can affect CO detectors. CO detectors are electrochemical sensors, which
detect a variety of specific gases. In most cases, the gas of interest
reacts with the chemical solution in the sensing electrode to produce
ions (charged particles) that move through the solution to an
electron-accepting electrode, completing an electric circuit. The number
of ions produced and the magnitude of the current developed are
proportional to the concentration of the gas being measured.
Additional 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.
Fire Engineering, September, 1996. ===================================
Learn something new every day! And unfortunately, sometimes at night too.
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