battery backup

[k_ogre]

anyone ever try a computer back up? you can get one for about $50 that at 400w should keep a resmed a10 running for over 4 hours

[archangle]

anyone ever try a computer back up? you can get one for about $50 that at 400w should keep a resmed a10 running for over 4 hours

Do you mean a UPS?

If so, post the particular model you're talking about and your pressure settings for the A10.

[k_ogre]

the power supply for the a10 is 90 watts (could be wrong) and any ups (just did a quick look for a cheap one ) so regardless of the settings the a10 can't draw more than 90 watts

[archangle]

the power supply for the a10 is 90 watts (could be wrong) and any ups (just did a quick look for a cheap one ) so regardless of the settings the a10 can't draw more than 90 watts

How are you calculating the 4 hour number for how long the UPS will last?

[k_ogre]

yes at 400w

[Woody]

That 400w figure is just how much the supply can deliver for a very few
minuets. Most of these will be powered by a 12v 7a battery or smaller and
figuring on 90% efficiency that would let it supply 76w for one hour. Now
to 1 other problems. When you have a power failure and the UPS takes over
it starts beeping at you. If you are asleep it will definitively wake you up at
least the 2 I have will bother you if you are in another part of the house. So
that's why even though I have one I also have a real battery backup to plug
up during a power failure.

[CapnLoki]

anyone ever try a computer back up? you can get one for about $50 that at 400w should keep a resmed a10 running for over 4 hours

You're going to have to be a lot more specific with your claim. First of all, its hard to find a 400 Watt UPS for $50. Amazon has some "400 VA" for $50, but they are actually only 200 watt. Generally 400 watts cost up to $120 or more. Second, the rating of 400 watts only means that it can put out 400 watts for a few minutes. What you need to know is the Amp-hour rating of the batteries.

The higher quality UPS's have batteries very similar to what have been discussed here lately, AGM (sealed lead-acid) usually sized about 7-18 Amp hours. For example, my computer system UPS is an APC 550ES rated at 330 Watts, and cost $55. The battery inside is 7 Amp hours. However, since the output is only 120 Volts, the battery is run through the UPS inverter so its only capable of the equivalent of 4 Amp-hours comparing to a direct 12v setup. Moreover, the UPS will shutdown before the battery is killed so its probably only going to deliver about 3 Amp-hours. This would actually run a CPAP for 1-4 hours, depending on the pressure, but if humidity and a heated hose are involved the time drops to well under an hour. This is why the ResMed recommendation for running of a battery with humidity starts at 30 Amp-hours and goes up to about 80. 7 Amp-hours doesn't get you much.

(As an aside, the APC system is pretty good for $55 - a good, though small, battery, a quality charger and inverter, plus software the shuts down the file server before data is lost, while keeping the the cable modem and router going so WiFi stays up, at least for 15 minutes. A handy gadget!)

The system I've been pushing as CPAP backup uses the same type of battery, but 35 Amp-hours so it can make it through the night. It can be run in UPS mode, though I confess I only do that if a storm is threatening.
viewtopic.php?t=102775

[Sleeprider]

Many UPS have built in alarms to warn computer users to shut down. They are intended to provide power until the computer is able to be safely shutdown. Most do not operate for an extended period with a load. The alarm function would wake you up anyway. It seems that if you want the ability to switch to a battery source for an extended blackout, you'd be better off with an appropriate battery solution that avoids the use of an inverter to power the machine.

[archangle]

yes at 400w

If you're responding to me, 400W has nothing to do with how long it will last before the batteries die.

Tell us a specific model of UPS, and if it has useful specs, I'll tell you how long it would last. Most decent UPS's have a graph that shows you that with x watts load, it will last y minutes.

For instance, this 550 VA model would last 28 minutes at 100 watts, and 1 hour 8 minutes at 50 watts.

My S9 machine averages around 30 watts, blowing 16 cmH2O and running the humidifier, but no heated hose.

It might actually be somewhat useful. Many of my power outages are less than an hour.

If you get a UPS, be sure you can turn the beeper off if it beeps when power fails.

[dcell59]

I think that the alarm is the biggest problem with most UPS units. It used to be common to allow them to be turned off, but the ones I've had for the last 10 years or so don't allow that. On some you can cut the wires.

What I do is to keep my travel unit handy and charged and if my main unit stops working I can switch over. I don't require the humidifier, though I do use one, so it's no big deal to switch. If my CPAP machine goes off, I will know it.

[RogerSC]

I think that the alarm is the biggest problem with most UPS units. It used to be common to allow them to be turned off, but the ones I've had for the last 10 years or so don't allow that. On some you can cut the wires.

What I do is to keep my travel unit handy and charged and if my main unit stops working I can switch over. I don't require the humidifier, though I do use one, so it's no big deal to switch. If my CPAP machine goes off, I will know it.

I've had several UPS's over the years, and just got a new one about 6 months ago (1500VA), all of them have allowed turning off the alarm, including the latest. With our dog, that's a must *smile*. I was buying a couple of the lower powered ones, which also allowed their alarms to be disabled, this time I decided to go with one large UPS. Maybe it's the brand of the UPS's that you buy? This latest one for me is by CyberPower.

And you should be able to find out about that before you buy it, pays to do your research.