Backup Power-Power Inverters/Unitteruptable Power Supplies

[AltPwrPuffer]

HI All,

Just some info for the folks seeking info to survive when the power goes out. When we have to rely on electrical devices to survive, we soon realize that what we always expect to be there seems to let us down at critical times. Before cpap it didnt seem to be all that important, so with that thought here is some info.

Unitteruptable Power Supplies, inside that box sits an inverter, ac switching, battery charger and a battery. The inverter in the lower price units are generally a MODIFIED SINE WAVE unit, which has been said on this site to be avoided for different reasons. The batteries in these units are generally too small to provide a nights run for cpap units especially running a humidifier. The larger units will have a pure sinewave inverter and a larger battery but will still only provide a modest amount of performance when we end up looking at days or perhaps over a weeks time without power.

Inverters, they come in various sizes, modified and sine waveform, plus different input voltages from 12 to 48 volts. The larger ones also come with built in AC switching and battery chargers like the unintteruptable power supplies, add batteries, wire in your house power and you have a far better unintteruptable power supply.

Small inverters for the most part are inexpensive modified sinewave units that run on 12 volt power, power that you find in the various vehicles that we use from the car, boat, motorhome, etc. They can be had in power from less than 100 watts to 1000 watts for $100 or less. They will power a great amount of different equipment if sized properly.

Here's one example http://www.invertersrus.com/xp400.html

Small sinewave inverters can be had but a 150watt unit starts at $100 and the 300watt unit needed to run our cpap machine can run $140 or more depending on the quality of the unit. They also do not have the surge capability to start larger equipment

Here's one example http://www.invertersrus.com/inv300ps.html

Large inverters, 1500 to 3600watts, can be had in modified or pure sinewave also but generally include a built in battery charger with ac switching. With the addition of a battery bank and your house ac wired into them you can run your cpap machine, lights, TV, and refrigerator for days depending on the size of your battery bank.

Here's some examples of modified sinewave units: http://www.solardepot.com/dpc_inv_mod-sq-wv.htm

Here's some examples of pure sinewave units: http://www.solardepot.com/dpc_inv_sinewave-trace.htm

The large inverters run from roughly $600 to over $3000 dependending on wave form and functions but when it comes down to surviving these inverters could support you without much effort and then if you add a 5000 watt generator and some fuel, for weeks!

I have run my house with a Xantrex DR2424 modified sine wave inverter since 1995 with no problems. The Sanyo 32 inch TV doesn't care, the Dish DVR satellite system doesn't care, the KLLM home theatre doesn't care, 2 laptops and 1 desktop don't care, the refrigerator don't care, everything that I have plugged into that inverter runs without any problems. Since May of 2005 I have been running my cpap equipment on it, never had a thought about it until I read on this site it was a no no, hmmm.....

Well, the Remstar Pro/Cflex & HH and now the Remstar Auto/Cflex & HH run just fine. The little Fisher&Paykel HC100 humidifier cycles just fine, the little green lightes show me that, great little unit, I like it better than the Remstar unit. Perhaps the unfortunate ones that had problems had different brand units, that would be an interesting bit of information. I had ran the Pro since May 2005 till a few weeks ago, we will see what the Auto does.

But, of course, if your are fortunate not to need a Humidifier, the Remstar Auto manual says that it will consume up to 1.7 amps of your 12volt power. My thoughts, 2 six volt golf cart batteries in series, 12volts eh, 350 amp hours should give ya about 20 days or so, charge them weekly and puff on!

Darn long post, but with people suffering, this info is needed! If I can help, please ask, I'm willing, Charlie

[parker]

Charlie,

Well it's a long time since you made your post but it came up when I did a search. Seems like you are technical and I hope you can deal with some uninformed questions.

I live in Seattle and had a 3 day power outage which was inconvenient to say the least since I am addicted to my auto cpap. Power is back on on.
After the first night I moved into a hotel with power and got a couple of nights sleep but that can be kind of expensive if there is a better solution.

I am not rolling in dough but I have enough that I would prefer an optimum solution for sleeping instead of cost.

First off, you say you run your house on an inverter. Do you mean you you use it whether your ac power is up -- or not? Or are you in an area where your power is highly interrupted.

I am trying to understand the implications of using an inverter. If you have an inverter -- why do you need a generator?

[AltPwrPuffer]

Hi Parker,
I live in the woods on 50 acres without any power lines to the property, so we provide our own power with solar panels and a wind generator and use a diesel generator to supplement the system when the sun or wind doesn't provide enough input into our modest system.

Don't let the equipment scare you, it's simple, the technical part is what is inside the box that we can't deal with anyway. You size the inverter for how much power you need, size your battery bank to support that power, and then decide how to charge your batteries. You can use the regular ac when its up, use solar panels, wind generator, or engine generator, just depends on your needs and wants.
Charlie

[ColoZZZ]

Charlie,

Great post with tons of detail. Electricity has always eluded me and I'd like to figure out what kind of battery I'd need to run a REMstar at 10 cm H2O with heated humidifier (on low setting) for a specified number of hours. Can you give me the equation to use to figure it out so I can walk into a battery store and get what I need? My hope is for a dual use portable/backup power supply that I could get a couple of nights running w/ HH with a battery weighing less than about 25 lbs. and recharge it during the day using a portable solar collecter.

Speaking of photovoltaics, I'm also curious as to how I'd set up a small (3' x 3') solar panel to charge said battery and would appreciate any references you may have.

Thanks,

--Andy

[Bearded_One]

ColoZZ; I am assuming that the 3' x 3' photo voltaic that you are speaking of is rated at 12 volts. You will need a regulator.

http://www.sailgb.com/c/solar_panels/
http://www.etaengineering.com/regulators/pbr.shtml

You will not be able to run a CPAP and a HH for 16 hours on a battery that weighs 25 lbs, although you can probably run your CPAP by itself for 16 hours -- and you won't need an inverter. HHs use MUCHO current.

As an example, an Optima model# D51 12V battery will provide about 41 AMP/HR. It will weigh 26# and measure about 9.25 x 5.0 x 9.0" http://www.1st-optima-batteries.com/ YMMV

An interesting set of solutions is at http://www.sleepzone.com.au/, which consist of a 12V CPAP, passover humidifier, and an Aussie Heated Hose.

One solution is a Tyco GoodKnight 420G CPAP machine, Tyco passover humidifier, and Aussie heated hose. According to the website, the total current draw at 10 cmH2O is 21 watts, which means 26 hours from a 55 AMP/HR 12V battery. This should give you about 2 night's use from a 26# 41 AMP/HR battery. YMMV. The GoodKnight 420G has an especially low current draw, your REMstar will draw more current than a GoodKnight 420G.

[AltPwrPuffer]

ColoZZ,

The Bearded One is correct about your battery size when wanting to run a humidifier.

To figure, you can use a couple of formulas to find your power needs in order to size your battery.

My Remstar Auto specs say at 120 volts it uses 1.0 amp max so:

120volts X 1amp = 120watts

The Remstar HH spec says at 120volts it uses 1.7 amp max so;

120volts X 1.7amp = 204watts

So if you sleep 8hours: 120watts+204watts=324watts

324wattsX8hrs=2592watthours/day

To figure your amp hours, you divide your watt hours by the inverter voltage,

2592watthours/12volt inverter=216amphours/day

So you would need a battery that could supply you with 216 amp hours, of course this is a maximum equipment draw situation.

To find your equipment power requirements you could purchase a Kill-A-Watt meter http://www.sustainabilitysystems.com/products.php?cat=8 and then size from there.

According to my Kill-A-Watt my system was running at 123watts last night,
123wattsX8hrs=984watthrs/12volts=82amphrs/day, still more than a little battery can handle.

The Remstar says it needs 3amps @ 12volts, 24amp hours/night, but that would mean your humidifier would be used as a passover.

Solar panel sizing is amp output of the panel times the peak solar hours for your area. For instance a 3amp panel and 5 peak hours (approx for your area) 3ampsX5peakhrs=15amphrs production from the solar panel.

Hopefully this information will help you decide which way you need to proceed.

[Patrick A]

Great info

[clarenceh9]

Would this work from QVC "XPower Plus Powerpack/Compressor 200W Inverter & Jumpstarter" item # V22464 for QVC Price $72.75
Shipping and Handling $9.47

[AltPwrPuffer]

It would more than likely run the Auto but it wouldn't run the HH at the same time, plus the battery is unlikely of sufficient size to run it a full night. I use a Cobra 800 watt inverter in the big truck when I'm out over night and it runs my Remstar /Auto and HH no problem but alas the truck runs all night providing plenty of power.

[Bearded_One]

QVC lists quite a bit of information about the unit but it gives no information concerning the weight or capacity of the battery. From what I could find on the net, a unit similar to the "XPower Plus Powerpack/Compressor 200W Inverter & Jumpstarter" weighs 14 pounds. Of that, I would guess that no more than 10 pounds would be for the battery. A Guardian # DBG-1212 weighs 9 pounds and is rated at 12 Ah. A 12 Ah battery should run a typical 12 volt CPAP machine (with no HH) for one night, but it will be nearly dead in the morning. This sort of use could cause a short life span for a battery.

For a few dollars more you could get a Sears "DieHard Portable Power 950 with 12 Volt Outlets and Light" which has an 18 Ah battery but no inverter or air pump. This one would run your CPAP all night without even breathing hard.

[Patrick A]

Would this work from QVC "XPower Plus Powerpack/Compressor 200W Inverter & Jumpstarter" item # V22464 for QVC Price $72.75
Shipping and Handling $9.47

I would say you would be netter off getting th 400 watt version I tried using the above version and it did not last for more than 2 hours. I had to plug into the cig. plug off the chassis of my mh .