What happens if the power goes out?

HP,

I don't trust or know if I have any "knowledgable sources" around. So can you answer this? What measure is on the box for a UPS for an output rating? Seems to be watts from what I can see online at Stables and Circuit City's web sites?

Can you relate your calculations to this measure? I run the same brand APAP as you do but at 13 pressure (10-15). Since my pressure is higher than yours I need more output for the same length of backup I am sure. I also doubt that I need more than 4 hours since I don't think the power will go off right at bed time (or I would just do without APAP) or stay off all the way until morning. I am mainly looking to avoid the unpleasant wake up suffocating jolt. Can you show me a wattage calculation for this? Or with your pressure so I can get an idea?

[quote="snoregirl"]I am also very interested in battery backup. However when I go to a store to look, I can't tell which I should get.

Wally, could you post any more information on that APC Backup Pro 1100 that you have? In case you have had it a while could you give the specs in case there are new models that replaced the one you listed? Any idea how long it would go if just he APAP were attached?

I would rather go with one that someone else has tested.this unit? I have a Remstar Auto. Can I just plug it in the battery backup or do I need an adapter for it? I don't want to damage the APAP.

I have a Sam's club right down the road!

Thanks

There's also a form you can get from your electric company, which if your doctor signs it, the power company will give you enough power to run whatever medical equipment you need. The form basically says that you need to run your equipment even in an emergency. I did not think my case was bad enough to warrant asking my doctor to sign this. But maybe some of you do.

Caroline

The power went over in my neighborhood (SW Austin) for 3 hours last night. Fortunately, I was off today. I had only been to sleep for about 2 hours before the power went off. After it came back on I slept another 5 hours. I think I dozed off during the 3 hours and interestingly enough my breathing patterns had changed in my 1 week on CPAP. I'm now breathing more through my nose, when before it was always through my mouth. This is according to my wife.

I think a UPS is possibly in the future. I saw one that was up to 145 minutes. That was the maximum I could find. That wouldn't have cover the 3 hours but it would've helped for 2 of them.

you also need a conditioner charger - that was why I suggested the Heart Interface. $550 on ebay, they will condition, charge and provide AC from the batteries.

[quote="snoregirl"]I am also very interested in battery backup. However when I go to a store to look, I can't tell which I should get.

Wally, could you post any more information on that APC Backup Pro 1100 that you have? In case you have had it a while could you give the specs in case there are new models that replaced the one you listed? Any idea how long it would go if just he APAP were attached?

I would rather go with one that someone else has tested.this unit? I have a Remstar Auto. Can I just plug it in the battery backup or do I need an adapter for it? I don't want to damage the APAP.

I have a Sam's club right down the road!

Thanks

In this discussion, I will attempt to answer the question, "What size battery backup do I need for my xPAP?" I will also talk about how to make the backup bigger.

Battery Backups are rated in "KvA". you get kva by multiplying amperes times volts and dividing by 1000.

We can read the UPS FAQ http://www.jetcafe.org/~npc/doc/ups-faq.html but I'll try to net it out. It really does not tell much about our question - because the UPS distributors don't give that much information.

The rating on the front of a UPS is for instant draw, and it is also, frequently, an average number. You therefore want to get about twice as many KvA as you need. Since the xPAP probably draws a max of 125 watts and the smallest UPS devices run about 350 KvA, if all you run on the UPS is the CPAP, you are likely OK, even with the smallest UPS and the xPAP, without a humidifier.

But the KvA number simply does not tell you the story about how long the UPS will last. This is controlled by overhead, efficiency, Amp-hours of the battery pack, voltage of the battery pack, and the phase of the moon.

In general, they put batteries with more Ampere hours into larger UPSs, but they do not have to - the other point is that there are a lot of things that go into, "How long does this UPS last under that load?"

Your appliance may be rated in kva or watts. For a DC appliance, va = watt. For an ac appliance, the ratio is about 100 kva = 80 kw and 100 kw = 125 kva. See http://www.macgen.com/calcul.html. The difference has to do with the inductance of the load vs. the resistance. I have heard that you might want to use conversion numbers as low as 0.6 for safety. as opposed to this site's 0.8.

So, you need enough kva to support the instant demand, and enough battery power to support it for a while, where you define what a while is. For some applications, three minutes is enough. For some applications, eight hours is not enough.

Respironics is not advertising the power requirements of many of their machines, at least not where I can find them. One machine I did see said that they wanted 1.25 amps max at the range of 100-240 volts, so let's assume that they mean 1.25 amps at 100 volts. Generally, you would draw more amps at a lower voltage to power the same wattage load.

Anyway, this indicates that the appliance draws about 125 watts. Got it? This is equivalent to about 160 va.

But this is an INSTANT draw - almost any UPS should be able to supply this, even the cheapest 350 KvA UPS. The remaining question is, for how long?

If all you care about is short outage bridging and a better surge suppressor, then you might be happy with this cheap 350KvA device - in that case, you spend $39.95 plus tax and you are done, or $59.95 to also power the humidifier - and it is a black square box that matches the respironics nicely. When I lived in Peekskill, NY and had ConED our power was close to perfect - no surges, no dims, no short outs, no drops. Once the power was supposed to go out on our street for 10 seconds while they installed a drop that they could not do hot. They sent out post cards to tell us to be prepared a week in advance and they promised that they would consider appeals if we had a reason that they should not cut our power for 10 seconds to install this drop. As far as I remember, that was the only outage that year. I bought a UPS and my friends asked me why.

South Florida is different. On the average I see 5 outages a day - if I did not have a UPS on my TiVO I would have holes in the middle of most of my recordings. My old Respironics had an odd feature - when the power came on, it turned on the CPAP even if it was off. So if there was a short outage, it would run all day with no load on it. I decided to put it on UPS to keep it from running all day several times a week. I'm too lazy and sleepy when I wake up to unplug it every day

In NY, I just left the CPAP plugged in, and this was not an issue. In Florida, I found that three days a week, when I came home, the CPAP was running.

Anyway, back to UPS sizing.

APC is the largest provider of home office UPS devices in the world. They have a sizer on their site - see their sizer for info - I sized the load by saying, ?minitower, celeron less than 1.5, one hard drive, no monitor, 20% power needed for backup.

This led me to the APC Back-UPS RS 800VA 120V Black which has a retail of $149. It runs, with this load, nearly two hours. It has one very important feature for computers - which might be less important for this application - Boost and Trim Automatic Voltage Regulation (AVR) - which means that the "cleanliness" of the power is dealt with, and the power passed through is either full time conditioned or monitored and conditioned when required.

See, generally, this grade of UPS does not do anything to the power that comes through. It looks at the power, and if the voltage goes high, or low, or there is a spike, it disconnects the outlets from the mains, and it turns on the inverter and supplies power from its internal batteries - converting the DC battery power back to 110V, 60Hz. This switch over takes time - click and it is done, but that click is still time. In many, you can hear them click. The changeover happens so fast that it does not affect most devices.

There is another kind of UPS. This sort of UPS has no direct mains connection to the output - it rectifies all of the input power to DC and charges the batteries with it - then it converts all of the output from the charger - or the batteries if the charger dies because there is no input power - and it makes that back into AC. There is no direct connection to the output. The output is always the output from the UPS as if the power were out and it were coming from the batteries - except that if the power is on, the batteries are being charged.

This is the one that should give you cleaner power - and there is never a surge on switch over, or a click. If there is a line surge, it is always arrested in the device because there is no direct connection from in to out. The devices we are looking at are the cheaper ones. Do you need to pay more for better power? This is a medical device - the power supply in the xPAP is a lot better than the power supply in your computer.

Let's see if we can determine what goes into the actual run time calculation. Nope - they have charts but no formulas. We could guess - like 80%-95% efficiency and simple volts-amps calculations, but we don't really know. We can't determine what the actual load of the internal inverter is and so forth. The charts they supply claim that they take that all into account - that they represent real world performance. OK, we will use a their chart.

APC's chart is at http://www.apcc.com/products/runtime_fo ... untime.cfm

We can try to interpolate a 125 watt load. Filter by 120v at the top and refresh. Now look between the second and third column - and interpolate - somewhere between a quarter and half way between. Pretty much everything is topping at about 90 minutes - the only one that extends that is the the BR1500+(1)BR24BP which is an extra battery - this will cost you about $350, as I recall.

The heart interface costs more, way more - but it can use huge, comparatively cheap batteries that will run all night and all day if this is the only load, or all night and a TV and the UPS if that is the load. I would strongly suggest putting the humidifier into passover if you can possibly stand it - if you can't, you need to determine what the draw of the humidifier actually is with an ammeter or wattmeter - or if you give me the watt rating, I will try to figure it out for you. But it will be a lot more. My guess is that a humidifier is about 50 watts.

The point is that the Heart Interface can supply 1000 watts (not 1000 KvA, as I recall) and if you want a lot of runtime, well, you can just add more batteries in parallel. Figure on three days to get power back after the hurricane? Run six big batteries in parallel. That simple - and it is designed for all this, automatic switchover, isolation, etc.

You could just install a separate inverter and a battery charger - the point there is, well, the batteries need careful charging and conditioning so that they give maximum life and capacity. This much battery will cost you hundreds of dollars - and if you overcharge it or undercharge it you will reduce its life. A first class battery charger will make the battery last years, a cheap one will kill the battery in short order, even a deep discharge. You need a three or four stage charger for optimum life. Get one that provides more amps than you draw - and the battery will last and you will have perfectly conditioned power. The Heart interface does almost all of this properly in a single integrated package. It does not do full time inversion. But it will keep your batteries alive.

The point is that you need something that is sized for more than small, short interruptions in power if you have a long term need. That technology is still expensive, and the expense is more than just the batteries.

Me? I use a BR500ish one (different model, same capacity) and I accept that I can only deal with a short outage - some nights I get a series of 10 or more 3-30 second power outages - that is something I am forced to accept, living in South Florida and that is what I am protecting against. I am specifically not protecting against a 4 hour outage - if that happens, I have to crank my generator or just wake up. Hurricane? Generator.

A while back, Walmart had a 1.5Kw generator - you plugged the item you wanted protected into the plug, and the generator into the wall. It was powered with propane. It had its own battery. In the event of a power failure, it automatically started and ran - providing power to one outlet.

That kind of arrangement is what I should have bought. I didn't.

But I have one more possibility. Some of the UPS devices use a 24 volt battery internally. If one were to take a couple plastic boxes that might hold batteries and connect two of those $90 walmart deep cycle batteries in series, then wire them to where the battery goes in the inverter. Well, it might take a week or more to recharge the battery after it goes flat. Someone I corresponded with said that his batteries took a month to charge - the size imbalance was so high. Now, with the tiny batteries, four hours of charge gave him 15 minutes of run, and that ratio held true. But he had a long, long run time with two walmart Deep Cycle batteries..

See, tiny load, big batteries, it might take 20-30 hours to discharge the battery. All the pieces that you need to do this are in the UPS: The DPDT switch to isolate the power line, the inverter and the battery charger. You might want to have an extra charger to bring the batteries up faster - but remember that unless you go special supply (24 volt - two batteries in series) you will need to charge them one at a time or use two chargers. And the charger in the UPS will be set up to charge a gel cell of small capacity - again, this is why something like a heart interface, which is designed to power an RV off the inverted 12 volts as well as charge and condition the 12 volt batteries and can do the right thing by high output gel cells or big wet cells is the RIGHT device for this - and why it costs a bunch.

Finally, there is only a tiny voltage difference between a fully charged lead acid battery and a partially discharged lead acid battery. The sensing circuitry in the UPS is likely very sensitive to small voltage changes and it expects to be physically close to a battery and it expects the wires to be fairly thick - if you are going to make these wires longer, they have to be way heavier - Way way heavier. Think size 4 copper or even heavier - and as short runs as possible. Suppose you have a ventilated space under the house - don't run DC wires down there through the floor --- put the inverter down there (shielded from the weather) and run the AC wires remotely. they can be thinner and they are not as length sensitive.

And, if you have never done a project like this, fitting a UPS into a power company circuit should not be your first. Get a Heart Interface or the commercial equivalent and pay an electrician to install it according to their instructions and to code.

I hope this helped someone. The high points:

The rating on the front of the UPS box is for instant draw capacity, not for run time. You should not load your UPS past about 60% of its rated capacity for instant draw. A 1500KVA may or may not provide a longer run time than a 800 KVA UPS - the draw capacity has little or nothing to do with the run time. This is very important because you should not exceed this limit, but a single xPAP is unlikely to exceed the draw capacity of even the smallest UPs. Again, the KVA rating does not have much to do with the time that the UPS will run at a certain load - except that the companies tend to put larger batteries in higher rated UPS devices - but not always.

A KvA is not a watt. It is between .6 to .8 watt, especially since the motor load in a xPAP is inductive. My best guess is that a CPAP is about 125 watts for Respironics BiPAP. If you have a different xPAP, look on the plate on the brick, or the box, or the instructions, or call them, or measure it.

The charts on the side of the box or on the web site are about the only good way to tell you how long this particular UPS will power this load. the KvA rating does not have anything to do with how long the UPS will last.

If you use a UPS and are happy with the charts, it is as simple to use as, "read instructions, plug into wall, plug device into correct plug on UPS." Follow their instructions over mine - there might be a tab to pull to engage battery. That is the best solution for most people who need UPS for short outages.

If you are into home-brew, you could use a UPS and somehow attach it to an oversized battery. This should only be attempted by someone who is familiar with wiring and confident in their experience and abilities - a mistake with power wiring could kill you, either by electrocution or in the resulting fire. Others have done this - One common hint is to make the low voltage lines as thick and short as you can. The best choice, if you can afford it, is a "Heart Interface" (or equivalent) which is commercially used for this sort of thing and which can be installed by an electrician.

[quote="brasshopper"]In this discussion, I will attempt to answer the question, "What size battery backup do I need for my xPAP?" I will also talk about how to make the backup bigger.......................................

...................................................The best choice, if you can afford it, is a "Heart Interface" (or equivalent) which is commercially used for this sort of thing and which can be installed by an electrician.

[quote="chdurie2"]There's also a form you can get from your electric company, which if your doctor signs it, the power company will give you enough power to run whatever medical equipment you need. The form basically says that you need to run your equipment even in an emergency. I did not think my case was bad enough to warrant asking my doctor to sign this. But maybe some of you do.

Caroline

I have been looking at the following UPS:

Xantrex XPower PowersSource 400.

http://www.preparedwithpower.com/backup/products.asp

This looks like a good candidate for providing power to an APAP unit during a power failure.

Only beeps once when the power goes out and the APAP switches to battery power.

Any comments from users with the more electrical knowlegable?

Specs seem to be sufficient for APAP purposes.

Since around here, the power can go off whenever. I purchaced one of these last year.

I know need to figure out if it is safe enough to have the APAP plugged into it all the time and the adapter for the eliminator into the wall outlet.

This is a Canadian link, but it will give an idea of what is available. I have not hooked up my CPAP to it yet, I need to read all the specs first.

http://www.canadiantire.ca/assortments/ ... 0413532356

A marine battery can be added for extra power.


I have one of the other units, and a marine outlet, but would need a car or something else to use it with. Maybe an idea for camping trips, with a car.

Smaller ones are also available. I bought this for general short term power outages. I am not equiped for any long term outage, especially in cold weather.

This is not your lightweight stuff here:

http://www.canadiantire.ca/assortments/ ... nt=primary


Anybody has any opinions or experience with either of these two items and xPAPs.

Last week we were using our motor home in a campground. The power pedestal had a power surge am I glad I had a srge protector plugged into my c-pap the power went out and it shut down my cpap.
And the alarm went off in my cpap machine loud enough to wake both my wife and myself up.

well i know this fails all scientific knowledge but i woke up last week to all my clocks flashing as if the power had gone out, the computer had been reset, as if the power had gone out, my modem lights screwed up as if the power had gone out.. YET my cpap was still blowing out air as normal as could be..... and my machine has zero battery backup.. just plugs straight into the outlet.

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CPAPopedia Keywords Contained In This Post (Click For Definition): CPAP, Power

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Lyza wrote:well i know this fails all scientific knowledge

Most (all?) CPAP machines will restart to their previous operational state if there is a power interruption. Its quite possible to have a short power power outage (say less than a minute) which is enough to get all the devices you mentioned to reset, but which you will not necessarily notice as an interruption to breathing while asleep.

When the power comes back on the CPAP machine will restart to it's previous operational mode, which if you were asleep would be blowing air (with no ramp up). Even if something else triggers you to awaken because of the power outage, by the time you reach even a basic state of alertness, your CPAP machine may seem to be operating normally.

Cheers,

Bill