Battery questions and other

[michaelthomas]

I've been using my CPAP for a few years now and I am quite used to it. When I lose power though, it has become a problem. I have looked in the past for a battery option, I know there is the CPAP one for $300 that claims to get 12.73Hr on my device and my setting (17).

I was looking for a cheaper alternative, that will hopefully provide more time. I would like to avoid building myself type system like the awesome post from JohnBFisher.

As a computer geek, my first instinct was a computer UPS, I can easily get a 500-1000VA unit for under $100 but I cannot figure out how long the unit would last on such a unit. I have a Killawatt meter and measured the device and comes out to .02kwh over the course of 2hrs and 8 minutes. Typically the run time on UPS units is not very high, but for $50-100 to get 1-2 nights I'd be happy.

I went through a lot of John's guide and considered putting something like that together, but it is very heavy and bulky, and I don't like the chance of fumes even in the case if I can avoid it. I am not much of a builder either, computers sure, anything else not really.

On another note, I noticed a lot of people have software in their signature, what is the main benefit of this? I can view leakage and my apnea rate from my device, I don't think I need much more than that even though I don't check that all that often anyway. Is there a real advantage to running the software?

Thanks!

[archangle]

Welcome to the board, Michael.

I believe you have the wrong machine listed in your profile. I don't want to be picky, but it matters in terms of how you can power it. Does your machine look like the picture on your post? Does it say Philips Respironics on it? Does it say "M-series" anywhere on it? Look on cpap.com and tell us what your machine looks like?

Most home computer UPSs are not made for this kind of usage. They are made for keeping the computer powered just long enough for you to save your files and shut down your computer cleanly when the power goes out. You will probably not get even a few hours on a cheap UPS.

The VA/watts rating on a UPS is useless for telling how long it will run. VA ratings tell how much instantaneous power it will put out, not how long it will put it out that much power. i.e. they help you tell whether it will power a particular device or not. It does not give you any hint as to how long it will run.

Any backup power supply that will power your machine for a full night will tend to be somewhat bulky, but not necessarily as bulky as a car battery.

Depending on what machine you have, the software will tell you things like what kind of apneas you're having, when during the night you're having them, how severe they are, how your pressure changes over the night, whether you're snoring, and several other things.

[michaelthomas]

I updated it, I picked one that looked like it, but I have the right one now.

[JohnBFisher]

Rested Gal has a thread that she maintains about Battery Backup setups.

I also put together the following thread on a Battery Backup Design:

viewtopic.php?t=49115

Hope that helps.

[moresleep]

What they said. Also, no free lunches when it comes to weight or other tradeoffs. Your lightest, most efficient, and most trouble-free configuration will be running your Cpap directly off a battery (assuming it can run directly off 12 volts); worst in all those categories will be running it off a UPS.

Deep cycle lead acid batteries (your cheapest option by far) are rated in volts and amp hours (AH). By your figures, your machine draws only about 10 watts (are you sure that Kilowatt meter is accurate at the lower end?), which would mean about 1 amp for a 12 volt battery. While deep cycle lead acid batteries can cycle deeper, if we assume 50% cycling, that means you need about 20 AH for 10 hours. That's about the size of a large jump start battery pack.

You mentioned reservations about hydrogen emitted from a large battery. Lead acid batteries all have the potential to emit gas while charging, whether large or small, whether in a UPS or standing alone. Wet cell batteries will emit gas. Sealed gel and AGM batteries have valves that will emit if pressure builds up. It's not a problem in the real world--see the calculations that either JohnBFisher or Archangel have done. If it were, medical equipment would not use these batteries.

Your best bet is a deep cycle AGM battery. It won't leak acid; and it will probably not vent gas. You can get them in small sizes up to very large sizes. A Batterytender or other float charger will keep it charged. Battery stores or boat stores such as West Marine will have them.

Cheapest would be a jump start battery pack, which has a charger and easy 12-volt hookup built in. These use AGM batteries but are not true deep cycle batteries, although they seem close enough. But, unless you want to experiment, get a model that others have used successfully for backup purposes, as not all work well for this. You would also want to make sure it had a float charger, as otherwise constant charging will ruin the battery.

[michaelthomas]

Rested Gal has a thread that she maintains about Battery Backup setups.

I also put together the following thread on a Battery Backup Design:

viewtopic.php?t=49115

Hope that helps.

I read your thread John as mentioned above. It is an excellent thread, and I was hoping for something a little more done for me. I can get a $300 battery from CPAP.com that will last 13 hours or so on my settings, but it is expensive for the run time. I will check out Rested Gal's thread and see if that helps. Thanks!

[michaelthomas]

What they said. Also, no free lunches when it comes to weight or other tradeoffs. Your lightest, most efficient, and most trouble-free configuration will be running your Cpap directly off a battery (assuming it can run directly off 12 volts); worst in all those categories will be running it off a UPS.

Deep cycle lead acid batteries (your cheapest option by far) are rated in volts and amp hours (AH). By your figures, your machine draws only about 10 watts (are you sure that Kilowatt meter is accurate at the lower end?), which would mean about 1 amp for a 12 volt battery. While deep cycle lead acid batteries can cycle deeper, if we assume 50% cycling, that means you need about 20 AH for 10 hours. That's about the size of a large jump start battery pack.

You mentioned reservations about hydrogen emitted from a large battery. Lead acid batteries all have the potential to emit gas while charging, whether large or small, whether in a UPS or standing alone. Wet cell batteries will emit gas. Sealed gel and AGM batteries have valves that will emit if pressure builds up. It's not a problem in the real world--see the calculations that either JohnBFisher or Archangel have done. If it were, medical equipment would not use these batteries.

Your best bet is a deep cycle AGM battery. It won't leak acid; and it will probably not vent gas. You can get them in small sizes up to very large sizes. A Batterytender or other float charger will keep it charged. Battery stores or boat stores such as West Marine will have them.

Cheapest would be a jump start battery pack, which has a charger and easy 12-volt hookup built in. These use AGM batteries but are not true deep cycle batteries, although they seem close enough. But, unless you want to experiment, get a model that others have used successfully for backup purposes, as not all work well for this. You would also want to make sure it had a float charger, as otherwise constant charging will ruin the battery.

Thanks, I tried looking at Deep Cycle batteries from BatteriesPlus that John mentioned, but they didn't give much information and didn't seem to have a lot of options in that regard.

I also noticed some rated Ampere Rating (20 Hr. Rate): 105. What does this mean? I understand a 14.4 AH rated battery will get me about 12.75Hr on my setup, but I don't get what 105 means when also linked with "20 Hr. Rate").

If I went the route of using a Deep Cycle battery, I'd probably pick it up locally since Amazon doesn't have much of a choice and most places have insane shipping prices and by the charger and case online. Ideally I would like to get 4 days out of the battery on my setup, I know I can get a DC adapter for my unit for about $25. I would also like to take it camping when going camping, if it isn't insanely heavy and bulky. Using the specs on the CPAP.com battery, I'm guessing a 38 AH battery will give me 4 nights based on 8 hours (I usually only sleep 4-6 hours).

I was looking at something like this, since it is quite self-enclosed and cheap, but will only last for a little over 1 night.
http://www.amazon.com/Schumacher-IP-125 ... 173&sr=8-1 and would probably not handle the constantly charge.

I would like to have my unit plugged into it all the time rather than having to deal with charging it from time to time if possible. I suspect it would draw more off the battery than a trickle charger can charge and will always leave it slightly uncharged. Not sure if it would harm the battery either.

[dtsm]

amazon.com sells the duracell 600 which is a solid backup battery that will run 10+ hrs of cpap without humidifier. And it's reasonably priced. i've used in for several power outages and never a problem.

http://www.amazon.com/Duracell-DPP-600H ... 939&sr=8-1

[michaelthomas]

amazon.com sells the duracell 600 which is a solid backup battery that will run 10+ hrs of cpap without humidifier. And it's reasonably priced. i've used in for several power outages and never a problem.

http://www.amazon.com/Duracell-DPP-600H ... 939&sr=8-1

That was was another one I was looking at.

[michaelthomas]

Rested Gal has a thread that she maintains about Battery Backup setups.

I also put together the following thread on a Battery Backup Design:

viewtopic.php?t=49115

Hope that helps.

Do you have a link to her post, I can't seem to find it.

Also, I had a few other questions.

I am at 17, and my AHI usually is around .5, but is at 1.0-1.3 lately (I had a leaky hose I just taped). Do I need to do another sleep study to find out what my current setting needs to be? 17 was prescribed a few years ago, and although I've gained weight, it seems like I could probably go lower. My leakage is usually around 40-55.

I suspect if my current unit ever breaks, I will probably get a totally different unit style. Is there a real difference between many of the newer ones? It seems they take more power.

[JohnBFisher]

... Do you have a link to her post, I can't seem to find it. ...

A search of "Rested Gal Battery Links", yielded ....

Here are some links to battery power put together by Rested Gal, Hope it helps.

viewtopic.php?t=9682

... I am at 17, and my AHI usually is around .5, but is at 1.0-1.3 lately (I had a leaky hose I just taped). Do I need to do another sleep study to find out what my current setting needs to be? 17 was prescribed a few years ago, and although I've gained weight, it seems like I could probably go lower. My leakage is usually around 40-55. ...

Any AHI of 5 or less is considered "normal" and does not require any further tweaking. Of course, if you no longer feel as rested, you might want to talk with your sleep doctor about it. But normally that's a great reading and should not require a new sleep study.

Of course, (always easier said than done), loosing some of that weight would help some.

... I suspect if my current unit ever breaks, I will probably get a totally different unit style. Is there a real difference between many of the newer ones? It seems they take more power. ...

Yes, they probably do take a little more power. As is always the case, there's no such thing as free lunch. The more the machine monitors, the more automatic its response to changing conditions, the more power the machines will use. To summarize the situation in one word: TANSTAAFL [ There Ain't No Such Thing As A Free Lunch ! ]

But in general, most of the units use about the same amount of power and are MUCH quieter than they were just a few years ago. Often the integrated humidifier and the quiet operation make the differences worthwhile. At least it is for me.

Hope that helps.

[michaelthomas]

Any AHI of 5 or less is considered "normal" and does not require any further tweaking. Of course, if you no longer feel as rested, you might want to talk with your sleep doctor about it. But normally that's a great reading and should not require a new sleep study.
Hope that helps.

Thanks again for all the answers.

Is a big no no to lower the setting to say 12-15 and see if my AHI stays considerably below 5? This of course would make the battery demands much less, but also make it easier for me to fit the mask, I always have to have it extremely tight as after a day or so of using a new mask it leaks from the sides like mad because of the pressure. I generally just keep tightening it and tightening it over time to fix that as it drives me nuts.

[physicsbob]

Lead acid batteries get less efficient the higher the current that you draw out of them. For a deep-cycle battery the manufacture will rate the battery at different discharge rates, the 105Ahr at 20hr rate means that the battery put out a little over five amps continuously for 20 hours to get a 105 Amp/ hour rating. If you discharged it at a higher rate that 5 amps it would not have 105 amp/hour rating but lower. I have had my cpap running off of battery power for two years, with the battery being continuously charged by a Battery-Tender float charger without any problems.
As I live out in the country we tend to get numerous power outages here, seven so far this year. It is so nice to be able to sleep all night and not have to worry about it. With the maximum rating on the battery charger of about 3 Amps the amount of hydrogen that could be produced is negligible to he point of absurd to be worried about an explosion or fire.

[michaelthomas]

amazon.com sells the duracell 600 which is a solid backup battery that will run 10+ hrs of cpap without humidifier. And it's reasonably priced. i've used in for several power outages and never a problem.

http://www.amazon.com/Duracell-DPP-600H ... 939&sr=8-1

Just realized that one you mentioned ( one I did look at a few months ago when I was trying to find a battery as well) is rated at 28 amp hours, according the CPAP.com 14.4 AH battery lasting 12.75 hours with my machine & my flow setting, this thing should last 24.8 hours! That's pretty damn good for a off the shelf portable unit. Provided it functions as well as it claims.

This battery has both AC & DC attachments, I assume I would be best to buy and use a DC adapter for my machine since one is available rather than using the 120V transformer and cable that is traditional used in the house?

[JohnBFisher]

... Is a big no no to lower the setting to say 12-15 and see if my AHI stays considerably below 5? ...

Nope. But be certain to monitor carefully, can change only one thing at a time. Changing too much or not too frequently can confuse the situation.

But don't be too surprised if your AHI score climbs pretty dramatically. That can often happen.