What UPS unit do you Recommend ?

[Labrat0116]

We had a power outage the other day and thankfully it only lasted a short time (5-10 minutes or so). It was a good reminder to me that I NEED to buy an UPS unit ?

What UPS unit do ya'll recommend ?

[iSnooze]

The following thread isn't about a UPS unit but you might find something useful for a back-up battery.
http://www.apneaboard.com/forums/Thread-...for-travel

[OMyMyOHellYes]

I don't think a UPS is well suited for me. We have occasional outages, usually late night/early morning and I wake up almost instantly when the air supply cuts off.

Generally, UPS systems are designed to give you time to shut off a computer gracefully, not run it for extended times. I've not found specs on any UPS that would give me great comfort. Especailly since a UPS would jump in while my APAP is running with heated humidifierr and climate line tubing. Increases the power consumption multiple times over.

I pull out a 35 AH SLA battery from the closet, set it next to my bed, unplug the S9, pull out the the Inetllipap backup and plug it into both the battery and the wall outlet. Put on the mask and go back to sleep. The 35 AH will run the Intellipap an estimated 4 nights at my average pressure - no heated humidity (though it will still go passive humidity) - and will automatically switch back to the AC power if it comes on.

If I didn't have the S9 as my primary, I would run the Intellipap with the battery set up on it all the time -

Question for the group - is the Respironics direct battery input? Does it auto switch with a preference to AC like the Intellipap does?

OMyMyOHellYes

[Shastzi]

What OhMy said.
Indeed, the UPS is a sprinter, and what you need is a marathon runner.
That means a pretty big battery and get the proper DC cord for your CPAP machine.
Do NOT use an inverter. An inverter takes your DC from your battery and converts it to AC
and then your CPAP power supply just has to convert the AC back to DC again.
That sounds kinda stupid doesn't it?
It also means that about half the battery power goes into powering your inverter and generating *heat*
As long is you stick with straight DC all the way to your CPAP machine you'll get about twice the endurance as
using the inverter.

Buyer beware.

[Labrat0116]

What OhMy said.
Indeed, the UPS is a sprinter, and what you need is a marathon runner.
That means a pretty big battery and get the proper DC cord for your CPAP machine.

Do NOT use an inverter. An inverter takes your DC from your battery and converts it to AC and then your CPAP power supply just has to convert the AC back to DC again.

That sounds kinda stupid doesn't it?

It also means that about half the battery power goes into powering your inverter and generating *heat*

As long is you stick with straight DC all the way to your CPAP machine you'll get about twice the endurance as using the inverter.

Good points.

I thought about using a 12 volt car battery w/400 Watt inverter. Appears to be a PITA really.

I do have a generator out back for an emergency. But that is really for extended power outages.... (4) hours or more. It's also a couple hundred feet from the bedroom. I'm looking for something that will power my PaP for up to (1-4) hours or more.

What about a high capacity UPS unit ?

[OMyMyOHellYes]

I thought about using a 12 volt car battery w/400 Watt inverter. Appears to be a PITA really.

I do have a generator out back for an emergency. But that is really for extended power outages.... (4) hours or more. It's also a couple hundred feet from the bedroom. I'm looking for something that will power my PaP for up to (1-4) hours or more.

What about a high capacity UPS unit ?

The inverter is terribly inefficient. The UPS is nothing more than a battery with a built in inverter. Terribly inefficient. Would it work? Yeah. For a while. How long? Don't have enough information.

To answer your question, you really need to figure out how much the System One unit you have eats in the way of current.

Resmed has a guide that tells you how many amp hours of battery capacity you need to run a ResMed S8 or S9 for one or two nights.

For example's sake, you could find it at:
http://www.resmed.com/assets/documents/s...lo_eng.pdf

DeVilbiss has the same kind of information, but I had to call their tech support line to get it. I've Googled it for about the last 15 minutes and couldn't find one for the Respironics System One units that is handy online, so you probably have a call to Phillips/Respironics in your near future.

There are a lot of variables that go into the calculation of power requirements: pressure (usually max - or somewhere between your average and max), heated humidification use, and the use of a heated hose. The "heated parts" of the system SUCK power compared to just the blower unit. I plan to shed all humidificaiton in a power outage to maximize battery life.

Using the information provided by ResMed and DeVilbiss I figured I should be able to get 4 nights on the DeVillbiss and up to 6 on the ResMed using a 35 AH 12V SLA battery (smaller than a car battery and weighs 24 lbs - about half as much as a car battery). If all I wanted was 4 hours, I could get by easily with a 6 AH battery weighing 4 lbs and 2.75"x3.5"x4" in size. A 12 AH at twice that size would probably get me thorough a whole night. If I was to continue running heated humidification and tubing, that 12[/size] AH battery may make it through only 2 hours for me.

IF I COULD WRITE IT IN MUCH LARGER LETTER I WOULD: YMMV

For any useful calculation of either battery size or the size of a UPS system you need to know what the System One consumes in your configuration (normal with everything for UPS and maybe pared back for battery.) If you went the battery route, you would also need a DC supply cord. I don't know if you need one of the Respironics dedicated cords (My ResMed requires the dedicated ResMed DC power converter - my DeVillbiss just takes a cord straight from the battery)

The Respironics site for DC options is:
http://sleepapnea.respironics.com/access...power.aspx

There may be other ways to skin the cat of finding power consumption - would just be handy if somebody that employed armies of electrical engineers, somebody like Phillips, would just make the information available.

[SuperSleeper]

Using the information provided by ResMed and DeVilbiss I figured I should be able to get 4 nights on the DeVillbiss and up to 6 on the ResMed using a 35 AH 12V SLA battery (smaller than a car battery and weighs 24 lbs - about half as much as a car battery).

Just a bit of info on this... I've written this on other threads, but a standard non-deep cycle 35 amp-hour sealed [SLA] (or unsealed) lead acid battery with only a 35 AH rating will not suffice for most folks on CPAP with heated humidifier. Yes, you can use it maybe one or two nights with a 2-3 amp draw by completely discharging it, but you'll end up with a ruined lead-acid battery in the end. You have to remember that with any types of lead-acid battery, the amp-Hour (AH) of 35 does not mean that you can use the battery at 1 amp for 35 hours. That's a common misconception. You don't have the full capacity available to you. If you discharge a lead-acid battery too low, it will be ruined for future storage capacity. I've said before that if you're going to be using any type of 12 volt lead-acid battery for most CPAP applications, it needs to be a deep cycle (true deep cycle or at least a hybrid "deep cycle Marine" battery (not just a car battery). In addition, it really needs to be rated at 100 amp-hours or greater to deliver adequate power without discharging the battery to too low a level - which will damage the battery permanently.

On UPS systems, I wrote this:

Yep, most home/office UPS units have very small batteries as far as amp-hour rating (even the larger ones). You'd be lucky to power a CPAP with heated humidifier for much more than 30 minutes. As JJJ indicated, you'd have to spend hundreds of dollars to get a high-enough capacity UPS that would power a CPAP for an entire night, and in the end, it would probably weigh much greater than a simple marine deep cycle battery that you could have bought for $80.

It's all about the battery in the UPS. Check the amp-hour rating. To properly get at least one or more nights of CPAP use, you'll need a battery with a 100+ amp-hour rating. In addition, you'll have to make sure that the battery is made for numerous deep cycle discharges. Keep in mind that a "100 amp-hour rating" does not mean that it will power your CPAP for 100 hours, it's simply a rating for comparison purposes and your battery drain will depend upon how many amps your CPAP and humidifier is drawing at a specific voltage over time.

Most common household UPS units have sealed batteries that are rated below 12 amp-hours - which may power a CPAP for a few minutes at best.

Buy yourself an $80 12-volt lead acid Marine Deep Cycle from the local Wal-Mart, K-Mart etc. with a 100+ hour amp-hour rating and you'll be okay. And keep in mind that amp-hour rating is completely different from the CCA rating (cold cranking amps). If there is no amp-hour rating printed on the battery, it's not a deep cycle battery and it will not work for numerous deep cycle charging.

Also, see this quote on discharging a lead-acid battery:

Batteries have Ampere Hour (AH) rating. If you divide AH rating of the battery by the Amp rating your machine you will get the number of hours the battery will power your machine. A 12Volt 120AH battery will last for 40 hours powering a CPAP machine rated at 12V 3Amp.

Not exactly:

Using that formula would assume that you're planning on depleting the battery completely down to a 0% charge, which is a big no-no with lead-acid type batteries.

Roughly, 11.6 volts is considered fully discharged (0%). You never want to do that to a lead-acid battery or you're ruin it.

Ideally, you want enough battery capacity so that you don't regularly discharge the battery much below 70-80% of capacity. That will preserve battery life to a much greater extent. Go below that 70% level too many times and battery lifespan decreases. Go below 40% a few times and you have a doorstop instead of a battery. In other words, in reality, you only have 60% of your battery capacity to work with (otherwise you risk ruining it).

The amp-hour rating for a battery is the maximum amps that can be drawn until the battery is completely discharged, over a specific time period. The effective amp hours available drops as you draw more amps. So a battery rated at 100 amp-hours (for instance) doesn't really have the capacity that the manufacturers claim.

Battery manufacturers do tests on the battery to give them an Amp-Hour rating. A typical time period for a test is 20 hours, but it varies... batteries are tested over different periods, such as 24 hours, 75 hours, sometimes 100 hours. Let's use a 100 amp -hour battery as example, just to make the numbers easier.... A 100 amp-hour battery tested over a 100 hour period (i.e. 1 amp drawn for 100 hours) will not have the same capacity as a 100 Amp-hour battery tested over a 20 hour period (i.e.-- 5 amps drawn for 20 hours)... If you drew 1 amp continuously from a 20 hour test battery, it would last about 110-120% longer than on a 100 hour test battery.

Suppose you have a 100 amp-hour battery, tested over a 20 hour period. 100 Amp-hours divided by 20 hours = 5 amps. That means that the battery manufacturer claims the battery can sustain a 5 amp load for 20 hours until the battery is completely dead.

That's great, but wait... like I said, you don't want to drain a battery to it's completely dead 0%. On a lead-acid deep cycle battery, you should only drain a battery down to 40% of it's original capacity, absolute max. (in other words you've only got 60% of the battery to use).

On a 100 AH, 5 amp load, for instance... You have 20 hours of time at a 5 amp draw, but really you only have 60% of that time, so 20 hours x 60% = 12 hours.

Thus far, what I've said is true because I've used the same amperage over the same time period at which the battery was originally tested (20 hour rate). So what if you took your 100 amp-hour battery, but wanted to draw 10 amps from it until it was at the "safe" discharge level (say 60%)?

Do the math: 100 AH / 10 amps x 60% = 6 hours, right? Wrong.

The More Amperage You Draw, the Lower the Battery Capacity. So, the effective amp hours available drops the more amps you draw. Now, that 100 amp-hour battery is not what it says it is.

Ok, now, using a 100 AH, 20 hour test battery, at 5 amps draw, you get the full 100% of the battery rating (that's how the battery was tested in the first place, so you should get all 100%). But step up the amperage to 10 amps, and you will lower the capacity of the battery by about 10% (or 90% remaining).

That makes 100 AH x 90% = 90 AH / 10 amps draw = 9 hours x 60% (max safe discharge number) = 5.4 hours. And that's a difference from the 6 hours you thought you had.

Where did I get the 90%? It comes from Peukert's Equation... that's where the approximate 90% comes from. The Peukert Equation explains this... using it, you can predict how much time you'll actually have on a battery given a specific discharge rate.

The whole point is that the more you allow your battery to be discharged, the more you reduce your battery's lifespan. Even though you can discharge it to low levels, it's probably not wise to do so, so buy a battery that has a relatively high amp-hour rating to begin with so you won't have to worry about discharging it too low and keep your battery charged up if you can rather than allowing it to go below 70% of charge (which is about 12.3 volts). Keep in mind that I'm primarily talking about lead-acid deep cycle batteries. Other battery types can be discharged to a greater extent, depending upon their design.

Also, keep in mind that the above info is concerning lead-acid batteries, not other types such as Lithium Ion batteries, which have other criteria.

[Shastzi]

Just FYI there are devices around called low voltage battery cut-off's.
What it does is act as a pass through between your battery and load, when the voltage falls down to the critical level, it
disconnects the load (some can also squeek a warning tone and lights too!)

This will prevent pulling the battery "below the point of no return", so to speak. (around 11 volts or so?)

Bad news is:
These things are not cheap however, because they have to be heavy duty. Expect to pay $150+ for these.
Often they are used in Ham radio power supplies and automotive audio equipment.

Good news is:
If it saves your big battery once though, it will have paid for itself.

Cheers!

[Labrat0116]

Buy yourself an $80 12-volt lead acid Marine Deep Cycle from the local Wal-Mart, K-Mart etc. with a 100+ hour amp/hour rating and you'll be okay.

Great info (as always) people! Thank you!

Now, how do ya'll recommend recharging a deep cycle battery when it is INSIDE one's bedroom ?

I hate the thought of lugging one down from the 2nd floor, out to the garage to hook it up to my battery charger.



.

[Shastzi]

oh boy, now you got a new bag of worms to open.

Assuming its a sealed lead acid battery (non-spillable and won't vent hydrogen all over the place)

You should first disconnect the load (your CPAP 12v power supply might get fried.) then connect a battery charger to the terminals.
(make sure the battery is in a proper enclosure or battery box so some stupid idiot doesn't drop a screwdriver or pair of scissors across the terminals. ...Unless you want to see a section of the wall blown out of course...)

A good charger that will "top off" the battery and automatically shift into "float" mode should work fine. (follow reccomended charging rates posted on/with the battery)

Just be as careful as hell around this beast. The voltage is low but it is capable of astounding current flows.
Instant welding of large conductors (an open end wrench for example) followed by explosion and fire are not uncommon.
(maybe redundant for some but I state it nevertheless)
If you are skilled in servicing wheelchair power supplies you should be ok with this project.

Cool?

Play safe now kiddies!