Power outage - Backup did not work

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

by your "logic" gases in the atmosphere mix over time and become a homogeneous mixture... so, since hydrogen is *very* flammable when mixed with oxygen, we've got a combustible atmosphere here, and the first spark will blow up the world.

and it shouldn't be too much trouble to pull helium back out of the air to use for cryogenic purposes.

yer funny.

palerider wrote:

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

by your "logic" gases in the atmosphere mix over time and become a homogeneous mixture... so, since hydrogen is *very* flammable when mixed with oxygen, we've got a combustible atmosphere here, and the first spark will blow up the world.

and it shouldn't be too much trouble to pull helium back out of the air to use for cryogenic purposes.

yer funny.

Hydrogen and Helium are light enough to escape by reaching escape velocity in the upper atmosphere. The rate is low, but enough to keep the gases rare. CO2 largely gets sequestered in the ground and seawater, though the balance has been upset lately.

palerider wrote:by your "logic" gases in the atmosphere mix over time and become a homogeneous mixture... so, since hydrogen is *very* flammable when mixed with oxygen, we've got a combustible atmosphere here, and the first spark will blow up the world.

and it shouldn't be too much trouble to pull helium back out of the air to use for cryogenic purposes.

I wonder what the ultimate fate is of most molecular hydrogen in the atmosphere? I would expect it would eventually chemically react with something and combine into water or some other chemical. Hydrogen plus ozone would seem to be a match made in heaven. There's also ionized oxygen and even atomic oxygen at higher levels of the atmosphere.

As for cryrogenic separation of helium out of the atmosphere, helium is about 5 ppm by volume of the atmosphere. You'd need to chill 1 million parts of air to liquid nitrogen temperature to get 5 parts of helium. Doesn't sound very economical. I'm not sure it would work, either. The small amount of helium might dissolve in the liquid nitrogen.

CapnLoki wrote:Hydrogen and Helium are light enough to escape by reaching escape velocity in the upper atmosphere. The rate is low, but enough to keep the gases rare. CO2 largely gets sequestered in the ground and seawater, though the balance has been upset lately.

Supposedly, only about 3 kg of hydrogen and 50g of helium escape the earth's atmosphere into space per second. http://en.wikipedia.org/wiki/Atmospheric_escape

archangle wrote: I wonder what the ultimate fate is of most molecular hydrogen in the atmosphere? I would expect it would eventually chemically react with something and combine into water or some other chemical. Hydrogen plus ozone would seem to be a match made in heaven. There's also ionized oxygen and even atomic oxygen at higher levels of the atmosphere.

The large majority of it gets eaten by bacteria in the soil.

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!

Because I"m cheap. But I've adjusted my plans as I've considered different options and don't plan to keep the batteries in my bedroom unless needed. A French door opens onto my covered porch where I'll store them, plugged in with a battery tender. Any maintenance will be done out there.

And before you say, "but all wet batteries are maintenance free and you don't add water" ...

I wouldn't ever say that. I'm aware that deep-cycle batteries require maintenance or, at least, attention.

CapnLoki wrote:

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.

I have bigger issues to deal with.

First off, I live in Florida and have lived in Houston. As a result of hurricanes I've experienced multiple power outages of over a week's duration, in both places. We have hurricane plans but it we didn't need CPAP to sleep back then, so it didn't include power. Now, we'd survive without it but not sleep well. Being as conditions will be generally crappy, anyway, good sleep will help us get through it.

Also, my use for deep-cycle batteries is for more than CPAP. I have a camping trailer and would like to dry-camp on occasion. Most of the time I'll have shore power but would like to visit National Parks for 3-4 days, and many don't have electricity. Having a pair of batteries for CPAP backup helps me justify the expense of batteries for the trailer. My needs for camping exceed the capacity of the 35AH battery you describe. A pair of AGMs of sufficient capacity will set me back by ~$500.

So, my current plan is to get a Deka DP24 battery to match the one I already have. The one that came with the trailer is new. Yes, they're not much but the pair get both me and my wife through a long night with only about a 50% DoD. I'll store those batteries outside the door to my bedroom in a battery box customized with SAE plugs for quick connection. I'll keep our 12v adapters in a box near our bed, and keep a flashlight in the same box. Should we suffer a power failure in the middle of the night it won't be difficult to move the batteries (in battery boxes) 10 feet to my bedside, plug in, and go back to sleep.

I'll use the same batteries on my camper. We don't camp as often as I'd like so it's not like I'll be moving batteries every other weekend. I'll revise the connectors on the trailer to take advantage of the SAE connectors.

I also plan to get a small inverter generator. I'll use that to keep my refrigerator running and to recharge batteries as required. I'll take that generator with me camping to recharge there, as well. I don't intend to use it as a power source for cooking or AC, as others do, so it only needs to be able to handle the refrigerator.

When the pair of G24s gets old, I'll replace them with true deep-cycle batteries. But that will be a few years from now, by which time I will have recovered from the expense of the generator. Maybe they'll be AGMs but I'll make that decision based on my needs and means at the time.

Thanks for everyone's input. It resulted in changes to my plan.

CapnLoki wrote:

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.

Before stumbling on this thread today, I'd already reached the same conclusion after losing power a couple of nights ago for the first time.

I have on order:
* A 35 amp-hour AGM battery intended for wheelchairs & scooters. $63.95 with free shipping. I bought from an etailer in Brooklyn rather than Amazon to get quick ground shipping.
* A Deltran Battery Tender Junior to keep the battery topped up. $27.69 on Amazon Prime.
* A ResMed S9 DC-DC converter. $84.95 at an online DME in New Hampshire to get quick ground shipping. They had the A10 on sale for the same price.

I never hooked the power meter I own up to either of my APAP machines but the ResMed battery guide says my S9 with an unheated hose and no humidifier should pull about 1 amp out of a 12v battery at my settings. A 35 amp-hour battery should last for days on the boat and I don't have to worry about killing my battery bank. I can put a 25 pound wheelchair battery in a canvas boat bag and move it around pretty easily. With a ClimateLine hose and the humidifier running, I should get 5 or 6 hours out of the battery.

I opted to use the S9 instead of the A10 for a few reasons. I already own an unheated hose. The S9 pulls a bit less power than the A10. I own the S9 outright so if I drop it overboard on the boat or otherwise destroy it, I don't have to mess with my DME for a destroyed rental machine. The S9 looks to be a lot less fussy about power. I'm not sure I'd want to try an A10 with a generator or other funky power source.

The ResMed battery guide: http://www.resmed.com/us/dam/documents/ ... lo_eng.pdf

If I'm every faced with an overnight airline flight on a plane that didn't have power at the seat, I may splurge on a Lithium battery pack. The airline regulations to keep the battery under 100 watt-hours is really annoying. The ResMed Lithium battery is rated at 97 watt-hours. That will barely run the unit for 8 hours without a humidifier or heated hose. On an airplane with the dry air, I'd have to find some kind of passive humidifier solution.

GeoffD wrote: I have on order:
* A 35 amp-hour AGM battery intended for wheelchairs & scooters. $63.95 with free shipping. I bought from an etailer in Brooklyn rather than Amazon to get quick ground shipping.
* A Deltran Battery Tender Junior to keep the battery topped up. $27.69 on Amazon Prime.
* A ResMed S9 DC-DC converter. $84.95 at an online DME in New Hampshire to get quick ground shipping. They had the A10 on sale for the same price.

I never hooked the power meter I own up to either of my APAP machines but the ResMed battery guide says my S9 with an unheated hose and no humidifier should pull about 1 amp out of a 12v battery at my settings. A 35 amp-hour battery should last for days on the boat and I don't have to worry about killing my battery bank. I can put a 25 pound wheelchair battery in a canvas boat bag and move it around pretty easily. With a ClimateLine hose and the humidifier running, I should get 5 or 6 hours out of the battery.

I opted to use the S9 instead of the A10 for a few reasons. I already own an unheated hose. The S9 pulls a bit less power than the A10. I own the S9 outright so if I drop it overboard on the boat or otherwise destroy it, I don't have to mess with my DME for a destroyed rental machine. The S9 looks to be a lot less fussy about power. I'm not sure I'd want to try an A10 with a generator or other funky power source.

The ResMed battery guide: http://www.resmed.com/us/dam/documents/ ... lo_eng.pdf

If I'm every faced with an overnight airline flight on a plane that didn't have power at the seat, I may splurge on a Lithium battery pack. The airline regulations to keep the battery under 100 watt-hours is really annoying. The ResMed Lithium battery is rated at 97 watt-hours. That will barely run the unit for 8 hours without a humidifier or heated hose. On an airplane with the dry air, I'd have to find some kind of passive humidifier solution.

It looks like you have a plan. I've used my APAP for the last two summers on board my boat in New England, and have not even bothered to bring the the humidifier aboard. The only time I missed it is when a cold front went through in September and the temp dropped to 35 degrees. I use the house bank (ran an outlet to the bunk) since the 4 AH load doesn't strain my system much.

CapnLoki wrote: It looks like you have a plan. I've used my APAP for the last two summers on board my boat in New England, and have not even bothered to bring the the humidifier aboard. The only time I missed it is when a cold front went through in September and the temp dropped to 35 degrees. I use the house bank (ran an outlet to the bunk) since the 4 AH load doesn't strain my system much.

I only have a Marshall 22 catboat with a little 2-cylinder Yanmar diesel and a couple of small marine batteries. I don't run the auxiliary enough in typical use to push 20 amp-hours back into the batteries. I hate listening to the diesel. I can use the house battery if I manage to kill the wheelchair battery but I'd much rather keep both marine batteries fully charged to start the engine and run the nav lights.