On Fri, 03 Sep 2004 00:38:01 GMT, "ceraboy" wrote:
Bro Jack wrote:
Jack,
Dont fret about the hydrogen saturation problem. The buoyancy and
atomic size of hydrogen make it very, very unlikely to cause a
dangerous hydrogen content in your basement. During excessive
charging you will have a small excess of hydrogen gas very near the
terminals on your battery, so be careful about hooking up the
charging leads, but other than there is no worry about the furnace
or hot water heater lighting off hydrogen in the basement. Most
trickle chargers operate at 13.2volts / 1.5amps. The mere
milliliters per minute of generated hydrogen are not a cause to
plug and unplug your charger, although if you are really concerned
just put the charger on a timer and forget about it. Just check
your water level from time to time and add a bit of distilled water
if neccessary. AS long as you keep your battery topped off with
water you will not damage it with trickle charging.
Hi, and thanks.
The old charger resulted in a 256 on the CO sensor in the room with
the batteries and 75 on a sensor two rooms away. Someone said you can
estimate H2 by multiplying the CO reading by 2.5. This would be far
below the 40,000 ppm (4% saturation) danger level. Problem is that
the alarm sounds at these low levels and if I disconnect the sensors,
there's no way to know how high the H2 reaches. They're lead-acid
maintenance-free batteries, by the way. Someone suggested they be
replace with gel batteries.
Jack
The gelcells are designed to recombine nearly 99% of the hydrogen &
water which may be a good choice in your situation. I am quite
surprised that you are seeing such high CO readings, as I would not
expect that much hydrogen to be evolving. Where again in the CO
detector. I charge a sump pump battery in my basement 24/7 with a CO
detector (digital ppm readout) about 7 feet away around 4 feet off the
ground and never have been above 1 on the readout. You might consider
putting in a different detector to verify the data you are seeing.
Typically the standard home detector is a metal oxide type, which as
far I know is only sensitive to 10 - 15% actual hydrogen content. The
different types of CO detectors are listed below for your reference.
Also I came across a reference that indicated that the maximum rate of
hydrogen evolution of a standard lead acid battery is 0.42 liters per
amp per hour of overcharge. (0.21 liters of oxygen per amp per hour).
Also, contrary to typical representation in MSDS sheets for safety
purposes, the lower flammability limit of hydrogen in air is approx.
4%, while the actual lower explosion limit of hydrogen in air is
approx. 17%. These limits are empirical though and depend greatly on
the the ignition source and other variable. It is always best to be on
the safe side, but this may ease your mind a bit.
http://environmentalchemistry.com/yogi/periodic/H.html
Biomimetic (mimics body response) - usually battery operated, but
sensitive temperature and humidity, lasts approximately 6 years. The
technology uses gel-coated discs that darken in the presence of CO,
tripping the alarm.
Oxide Semi-conductor (most common) - usually plugged into wall, uses
Metal more power, sensitive to moisture, lasts approximately 5-7 years.
With this type, heated tin dioxide reacts with carbon monoxide to
determine levels of toxic gas.
Electrochemical (least common, more accurate) - expensive, battery
operated, short sensor life. With this type of sensor, three platinum
electrodes in an electrolyte solution generate energy when they react
with CO.
Original Charger: The CO sensor was 25 ft. away and plugged into an
outlet one ft. off the ground. The reading was 75 when the alarm
sounded. It is a Kidde Nighthawk CO sensor, direct plug-in. That
same day, the fire dept. got a 256 reading in the battery room, using
a hand-held sensor.
I bought a second Nighthawk, direct plug-in, and placed it 3 ft. from
the batteries, and 5 ft, high.
Second Charger: When the light is orange (charging) the highest
reading in the battery room has been 48. When the light turns green
(charged) the reading drops to zero, which means it could be anywhere
from 0-30 as it doesn't register below 30. The old sensor in the room
25 ft. away is more sensitive, it will show readings 0-30, but they
have so far been zero with the new charger.
I disconnect the charger at night for peace-of-mind purposes and
reconnect the next morning. It takes anywhere from 15 minutes to an
hour for the light to go from orange to green. If I skip a day, it
takes two hours to turn green.
Jack