Power outage - Backup did not work

palerider wrote:

archangle wrote:You know, you'd sort of think that, but gases don't seem to stratify that way once they have time to mix.

Oxygen has a molecular weight of 32. Nitrogen has a molecular weight of 28. CO2 has a molecular weight of 46. However, you don't end up with layers of CO2, nitrogen, and oxygen in the room. The O2 concentration is about the same at the ceiling as it is at the floor. Good thing, because with O2 being only 21% of the air, if it stratified, we'd suffocate if we got over 2 feet from the floor.

and yet, co2 pooling is one of the leading theories to explain SIDS, babies not stirring the air up enough to mix up the co2 they produce, and suffocating as a result.

so, your musing about co2 and oxygen and nitrogen includes saying that that hydrogen, at slightly over 2 molecular weight is going to hang around with that stuff that's what, 10, 15, 20 times heavier?

got something to back up your opinion?

The atmosphere is a couple of miles deep. The ratio of oxygen to nitrogen at 5200 feet altitude is about the same as it is at sea level.

Freon 12 CCl2F2 has a molecular weight of about 121 vs. around 29 for air. However, Freon 12 ends up getting up to the top of the atmosphere and damaging the ozone layer 10 miles or so above the ground.

Even in a tall enclosed space, you don't find that the O2 level is lower at the top of the building.

If you need more education, study up on gases. All gases are "miscible." That means that any gas will mix completely with any other gas in any combination. It's like alcohol and water, instead of oil and water. An alcohol solution will not form a layer of alcohol on the top, with a layer of water on the bottom.

When you first introduce something like hydrogen into an air space, the hydrogen will float to the top of the room because the hydrogen is not mixed with the oxygen and hydrogen. However, it will gradually mix with the air and dissipate throughout the volume of the room.

If you dumped an ounces of hydrogen into the room at once, yes, it would float up to the ceiling and be at a higher concentration for a while, but it would eventually mix and be a fairly even concentration. If you slowly leak out that same ounce over a few hours, it will spread throughout the room.

Look at what happens if you spill some liquid gasoline in an enclosed space. Gasoline fumes are about twice as heavy as air. However, the smell of gasoline will quickly spread throughout the room. It will start near the floor, but it will mix throughout the room fairly quickly.

Calculating how quickly gases will mix would be an interesting exercise. Please present us with your calculations if you are inspired to do so. I feel pretty confident that hydrogen would mix pretty uniformly throughout a room in much less than an hour. It would certainly do so within a day.

I presume that even when mixed, the heavier gases are at a slightly higher concentration near the ground but I might be wrong. They must not vary that much, or we'd be breathing pure oxygen and all the nitrogen would be in the upper atmosphere.

palerider wrote:and yet, co2 pooling is one of the leading theories to explain SIDS, babies not stirring the air up enough to mix up the co2 they produce, and suffocating as a result.

BTW, I didn't address that directly. First, I'm not sure whether that's proven, or is just speculation. However, assume it is true for the moment.

The explanation is that the the baby is consuming O2 and producing CO2 faster than the air currents and diffusion equalize the concentrations back to normal. The gases in the air will equalize once you stop adding gases, but it doesn't happen immediately.

The higher the rate at which you produce or consume a gas, the higher the gradient of gas concentration will be relative to distance from the source or with height.

It's similar to having an old gas stove. If one of the pilot lights blows out, you don't usually end up with an explosive concentration of gas in the house. If you leave on a burner and it doesn't light, you might blow up the house.

Folks, I appreciate your responses to my query but let's not turn this into a flame war.

chriscowles wrote:Folks, I appreciate your responses to my query but let's not turn this into a flame war.

Nothing wrong with a few flames - that's how I cook the popcorn! I do have to give archangle points for deriving from basic principles and agree that
when using a quality trickle charger the possibility of producing hydrogen from over-charging the battery is extremely low.

However ...

chriscowles wrote:... do other users here have standard wet cell batteries in their bedroom? If so, what consideration did you give to the potential for hydrogen gas posing a fire hazard?

Good Grief Man! Why would you want a wet cell in your bedroom??? Have you actually ever added water to a wet cell system? Wearing pajamas?? You should know that very corrosive acid splashes around when you do this! And before you say, "but all wet batteries are maintenance free and you don't add water" this is not true for a real deep cycle battery. When you leave a battery on a charger 24/7 it gets more time in a year than a car battery gets in its warranty lifetime, so there is a reason why they should be checked and watered, at least every 6 months or so. (Yes, I know in the past I've said a Walmart flooded battery is the most bang for the buck, but if you must go that route you'll be happier leaving it in the garage.)

chriscowles wrote:...The cost of AGM batteries is not within reach.

Why do you say that? The AGM battery I recommend is only $65 ... granted that's only 35 Amp-hours, but that should get you through the night, and even several days if you cut back on the humidity. If you expect longer outages you have bigger issues to deal with. This is the same battery my father and half the other tenants of his building have in their mobility scooters, and if they started blowing up I think it might make the news, even in Florida.

CapnLoki wrote:This is the same battery my father and half the other tenants of his building have in their mobility scooters, and if they started blowing up I think it might make the news, even in Florida.

What a development...


Little saturday morning humor...

CapnLoki wrote:Good Grief Man! Why would you want a wet cell in your bedroom??? Have you actually ever added water to a wet cell system? Wearing pajamas?? You should know that very corrosive acid splashes around when you do this! And before you say, "but all wet batteries are maintenance free and you don't add water" this is not true for a real deep cycle battery. When you leave a battery on a charger 24/7 it gets more time in a year than a car battery gets in its warranty lifetime, so there is a reason why they should be checked and watered, at least every 6 months or so. (Yes, I know in the past I've said a Walmart flooded battery is the most bang for the buck, but if you must go that route you'll be happier leaving it in the garage.)

If you're splashing acid around the room, you're doing it wrong. I find a turkey baster or one of those car battery float testers is a good tool for adding water to the battery. You can suck up a controllable amount of water from a water container, then dribble it slowly into the battery cell. Even if you're pouring water from some more ordinary container, there's no reason to splash it everywhere if you're careful.

Even if you do splash liquid around the room, it's probably mostly the water you're adding, not the fully concentrated acid from deeper down in the battery. Don't fill it on top of your valuable antique wooden bedside table. If you do get a few drops of acid on things in the bedroom, it will probably leave a mark, but it's not going to make your bed explode or eat a hole in the flow.

Keep the battery in a battery box in case you overflow the water and add water carefully. Remember that you are supposed to add water up to the bottom of the filler tube, not to the top.

If you do have something happen with the battery acid run into the shower quickly and start washing it off. Other than getting it into your eyes, it's probably not going to do any major damage if you wash it off quickly. Wear safety goggles when filling up any car battery.

Yes, if you turn it over and spill the acid, you're going to be unhappy with the results.

I like to keep my standby deep cycle batteries on a float charger, and I like to plug the charger into a weekly electrical timer so it only runs a few hours once a week. That resets the charger once a week in case it gets electronically "confused" and limits the amount of time it can spend boiling away the water.

archangle wrote:

CapnLoki wrote:Good Grief Man! Why would you want a wet cell in your bedroom??? Have you actually ever added water to a wet cell system? Wearing pajamas?? You should know that very corrosive acid splashes around when you do this! And before you say, "but all wet batteries are maintenance free and you don't add water" this is not true for a real deep cycle battery. When you leave a battery on a charger 24/7 it gets more time in a year than a car battery gets in its warranty lifetime, so there is a reason why they should be checked and watered, at least every 6 months or so. (Yes, I know in the past I've said a Walmart flooded battery is the most bang for the buck, but if you must go that route you'll be happier leaving it in the garage.)

If you're splashing acid around the room, you're doing it wrong. I find a turkey baster or one of those car battery float testers is a good tool for adding water to the battery. You can suck up a controllable amount of water from a water container, then dribble it slowly into the battery cell. Even if you're pouring water from some more ordinary container, there's no reason to splash it everywhere if you're careful.

Even if you do splash liquid around the room, it's probably mostly the water you're adding, not the fully concentrated acid from deeper down in the battery. Don't fill it on top of your valuable antique wooden bedside table. If you do get a few drops of acid on things in the bedroom, it will probably leave a mark, but it's not going to make your bed explode or eat a hole in the flow.

Keep the battery in a battery box in case you overflow the water and add water carefully. Remember that you are supposed to add water up to the bottom of the filler tube, not to the top.

If you do have something happen with the battery acid run into the shower quickly and start washing it off. Other than getting it into your eyes, it's probably not going to do any major damage if you wash it off quickly. Wear safety goggles when filling up any car battery.

Yes, if you turn it over and spill the acid, you're going to be unhappy with the results.

I like to keep my standby deep cycle batteries on a float charger, and I like to plug the charger into a weekly electrical timer so it only runs a few hours once a week. That resets the charger once a week in case it gets electronically "confused" and limits the amount of time it can spend boiling away the water.

I rest my case.

archangle wrote:

palerider wrote:

archangle wrote:You know, you'd sort of think that, but gases don't seem to stratify that way once they have time to mix.

got something to back up your opinion?

The atmosphere is a couple of miles deep. ... They must not vary that much, or we'd be breathing pure oxygen and all the nitrogen would be in the upper atmosphere.

you could just say "no".

and for anybody who's interested, gases DO stratify if not stirred up, by things like convection currents and wind (outside) and forced ventilation inside... which is why we have fun stuff like: 29 CFR 1910.146 (page 4557, appendix B, section 4) which states that gases must be monitored at four foot intervals.

with pictures:http://www.worksafecenter.com/safety-re ... cation.pdf

The document you cite applies to "confined spaces". OSHA's definition is below. That doesn't sound like my bedroom.

By definition, a confined space:

Is large enough for an employee to enter fully and perform assigned work;

Is not designed for continuous occupancy by the employee; and

Has a limited or restricted means of entry or exit.

These spaces may include underground vaults, tanks, storage bins, pits and diked areas, vessels, silos and other similar areas.

chriscowles wrote:The document you cite applies to "confined spaces". OSHA's definition is below. That doesn't sound like my bedroom.

take a room, put a charging battery in it, close the door, no forced air... that's a confined space, physically.

sure, there aren't any osha regulations about bedrooms, but we're talking about the physical properties of gases, and the effect gravity has on them.

palerider wrote:you could just say "no".

and for anybody who's interested, gases DO stratify if not stirred up, by things like convection currents and wind (outside) and forced ventilation inside... which is why we have fun stuff like: 29 CFR 1910.146 (page 4557, appendix B, section 4) which states that gases must be monitored at four foot intervals.

with pictures:http://www.worksafecenter.com/safety-re ... cation.pdf

Gases DO stratify when first introduced into a space. They eventually mix and become equally distributed.

You need to monitor gases at various levels in an industrial confined space because it takes time for gases to mix. If, for instance, you spill gasoline in a confined space, the fumes will be concentrated near the ground at first until it mixes. An explosive gas detector at ground level will go off much sooner than on at ceiling level. A detector placed higher would eventually go off, but the one at a lower level would go off sooner.

Pour a little chlorine bleach on the floor of your bathroom with the door closed and the air conditioning off. You'll probably smell it first at floor level, but you'll soon smell the chlorine at head level. It won't simply hug the floor.

Here's a NIH document pointing out that the percentage of O2 in the atmosphere doesn't vary with height, even up to 15,000 feet. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1114067/

archangle wrote:

palerider wrote:you could just say "no".

and for anybody who's interested, gases DO stratify if not stirred up, by things like convection currents and wind (outside) and forced ventilation inside... which is why we have fun stuff like: 29 CFR 1910.146 (page 4557, appendix B, section 4) which states that gases must be monitored at four foot intervals.

with pictures:http://www.worksafecenter.com/safety-re ... cation.pdf

Gases DO stratify when first introduced into a space. They eventually mix and become equally distributed. ...

Heavy gases definitely stratify, especially when introduced in concentration without much movement. Boaters are ever vigilant for propane and gasoline fumes in the bilge. The day I came to the marina to purchase my new boat the salesman ominously said as we walked down the dock, "Don't be alarmed - your boat wasn't damaged at all ..." In fact a boat two slips away had blown up, destroying it and damaging the immediate neighbors, with only minor injuries to the owner.

There are neat experiments done in freshman physics labs, like using vinegar and baking soda to fill a glass with CO2, and then pour it over a candle to extinguish it. And there have been many cases of suffocation from swamp gas and CO2.

That said, eventually entropy wins out over gravitational potential and the gases will almost completely mix.

CapnLoki wrote:Heavy gases definitely stratify, especially when introduced in concentration without much movement. Boaters are ever vigilant for propane and gasoline fumes in the bilge. The day I came to the marina to purchase my new boat the salesman ominously said as we walked down the dock, "Don't be alarmed - your boat wasn't damaged at all ..." In fact a boat two slips away had blown up, destroying it and damaging the immediate neighbors, with only minor injuries to the owner.

There are neat experiments done in freshman physics labs, like using vinegar and baking soda to fill a glass with CO2, and then pour it over a candle to extinguish it. And there have been many cases of suffocation from swamp gas and CO2.

That said, eventually entropy wins out over gravitational potential and the gases will almost completely mix.

Yes, heavy or light gases stratify when you introduce them into a space. Then they mix and become unstratified.

Have you ever spilled some gasoline in the garage? Have you noticed that after a while, you smell it at normal nose height? You don't have to crouch down to the ground to smell it. It probably started off stratified near the floor, but didn't stay that way.

Pour your CO2 into a container and confirm that it's concentrated near the bottom by slowly lowering a candle into the container. Now leave the container alone for an hour and see if it's still stratified.

My old setup included a F&P HC150 humidifier run off a separate a/c cord. It worked well but my new setup included the humidifier and I misplaced my old F&P hotplate. Thing is with a battery unit the old one would stop the humidifier but the battery would keep the APAP going. I got a good start-er-up battery thing that has a battery bypass converter to power the unit when power is on. It stays plugged in all the time (per instructions) and works all night if the humidifier is off. I lost power one night with it on and didn't wake up until the unit died. Wish I could find my old hotplate. I can do without the hose heater but not humidifier.

archangle wrote:

palerider wrote:you could just say "no".

Gases DO stratify when first introduced into a space. They eventually mix and become equally distributed.

you keep saying that, yet you offer nothing other than your opinion as evidence.