What brand of inverter do you recommend?

I'm looking for a 300w Pure Sine Wave Inverter for Ron's CPAP. Which brand is the best? Been reading bad reviews of the Aims brand and that's the one the CPAP people are recommending. :hmmm:

[ShrimpBurrito]

I don't have any specific model recommendations unfortunately, but realize they will be expensive - probably around $300 for a 300 watt model. But why do you think you need a pure sine wave model? A visitor of ours has run a CPAP several nights on a cheap-o $25 150 watt plug-in type inverter like this:

http://www.amazon.com/Wagan-EL2405-1.../dp/B0017ONDXE

...and it worked fine. Granted, it wasn't particularly quiet, so if I had to use one consistently, I'd want to install a quieter one permanently in a secluded location, but they wouldn't cost more than ~$50.

Dave

The CPAP company recommends this type because of the electronics in his model. Did you read those reviews? Scares me when they talk about them smoking and burning up during use. When we travel, the CPAP isn't easily replaced (prescription from dr. , medical supply store etc.) so I'd like to err on the side of caution even if it's more expensive. Thanks for your input Shrimp Burrito.

[ShrimpBurrito]

Nope, I didn't read any reviews. I guess if you would be SOL if the CPAP died on a campout, then it might be best to error on the side of caution. I know they are difficult to replace - our visitors attempted to replace theirs while at our house, and it was an unbelievable hassle. In any event, I don't know why a modified sine wave inverter would cause a problem as it's probably DC powered, so any non-pure sine waves won't matter anyway.

Which leads me to another thought -- is there a transformer brick in the cord between the wall and the unit? If so, there should be some info on the brick that tells you the output voltage. The few CPAPs I've seen are all DC-powered, so once you find the voltage, you can simply find a DC-DC transformer. (The "brick", if you have one, is essentially an AC-DC unit.) Not only are they far cheaper (maybe $30-$50?) than a pure sine wave inverter, but they'll probably be slightly more efficient than an inverter as well. That means more usable battery power for you. And the power they'd put out would be identical to the power it currently sees when you plug in at home.

If the output voltage is 12VDC, that's even better - you won't need a transformer at all. Just a $10 plug to go from the cigarette socket in the TM to the CPAP (assuming it has a detachable cord, which it probably does).

Not trying to dissuade your mission in finding an inverter -- just trying to save you some cash.

Dave

I'm getting close to needing a CPAP. A quick BING search of "CPAP 12V" shows a wealth of information.

You might want to buy a second CPAP unit just for travel...($279) -- 12v DC/100-240v AC:
http://www.cpap.com/cpap-machine/dev...ne-system.html


Batteries just for a CPAP:
http://www.bestcpapprice.com/Compact...hr-_p_516.html
scroll down for run times at different rates..


http://www.cpap-supply.com/Articles.asp?ID=146
"Many of the sleep apnea machines we sell have a 12V input that allows them to be powered by a 12V battery. Having the ability to run your machine from a battery can be useful for traveling and it can also come in very handy during a power outage."


Woodalls Forum:
http://forums.woodalls.com/Index.cfm...g/1/page/1.cfm

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A BING/GOOGLE search of "CPAP INVERTER" may give you more help.

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[Bill]

Can you tell us the specific CPAP machine Ron uses?

I have several thoughts, but can't really address them without knowing what is needed.

1. How much power does your specific CPAP need? As has been said, don't buy more inverter than it needs - this is a case where "more" is not "better". An inverter tends to have lower efficiency at small loads. This means that it will draw more current from the 12-volt battery than it needs to, and your battery will deplete faster.

2. A second machine, specificlly chosen to operate from a 12-volt supply, might be a good idea. It would eliminate inverter losses. Bring the original machine with you for emergency backup, but use the other for normal operation.

3. What happens if the CPAP machine fails to operate in the middle of the night? Does it beep or buzz to wake you up and warn you? Or does it just quietly sigh and die?

4. Will you have a spare battery? In other words, what is your plan if the TM battery dies in the night, for whatever reason? A motorcycle or lawn tractor battery can be an excellent backup - small, cheap, and easy to carry.

5. Does your CPCP machine operate on foreign power, or 220 volt power, or 50 Hz power? I bet it does. What this means is that its internal power supply can handle almost any power it receives. Foreign power is often far worse than modified sine wave.

6. Finally, if the CPAP manufacturer can't build a machine that will handle modified sine wave (which isn't that far from true sine wave), I'm not sure I'd trust them to build the machine itself. Does your CPAP mfr also make and sell inverters?

Bill

Thanks for the questions Bill. Ron uses a Fisher-Paykel HC221LE with a humidifier attached. CPAP.com recommends the 300w Pure Sine Wave Inverter.

I tried a 2nd machine run on battery but Ron doesn't like the way it breathes, so no dice. It didn't seem to have the power for the positive force that he is used to. They are all set by prescription, so I'm not sure what the difference is between battery and standard power.

When the power goes off, the machine "quietly sighes and dies". It is still distinctive enough that he wakes up at power loss. This last trip, the generator had a problem in the middle of a huge thunderstorm. Unable to work on it, we were without power for several hours.

A spare battery is doable; we're able to carry a little bit more with the Avalanche. This is only being considered as an emergency backup, not an answer to boondocking.

The machine does switch to 220 with an outlet converter. I don't know if Fisher-Paykel makes or sells inverters.

I really appreciate your questions and hope you can help me come up with some answers to my dilema.

[mjlaupp]

Judy,
You may have a better chance of getting the answer you need on the Sleep Apnea Support Forum:
http://www.apneasupport.org/

[Brittany Dogs]

My brother uses a CPAP and he goes camping and needs to use the CPAP also for hunting camp. The first attempt was to use a Honda generator all night when he had the 120VAC model. It was a pain and would not be allowed if he was trailer camping running a generator all night long. So he found a 12VDC battery model CPAP that uses a "brick" AC to DC power supply when plugged in at home. So not only does this unit run on it's own battery which is good for about 2 nights, it then can be plugged into a deep cycle battery to use for another 2 or 3 nights. The battery he uses is what we call a "wheelchair" battery, a sealed lead acid battery the size of a group 24 battery that is cut in half or about the size of a lawn tractor battery.

So his new CPAP has an on-board battery and when that runs low, he uses the wheelchair battery. It works great in his opinion and sure beats running a generator all night at hunting camp.

Lastly, most inverters are modified sine wave and it has a "choppy" sine wave that upsets some electronics but not all electronics. The CPAP machines have a small compressor in them that might tolerate the choppyness of the signal but the control board electronics may not. A safe bet is a true or pure sine wave inverter and they are more expensive.

But an inverter is about 65-70% effecient and that is less favoriable than certainly buying a good 12 volt CPAP capable machine.

Thanks for your input! I checked out the sleep apnea forum and got a lead on a battery pack geared for the CPAP Ron uses. Expensive! But rentable! Still not sure what to do; the battery pack would cost as much as a new machine..... We can't do that until November, when he sees the doc. In the meantime, we have a 10 day trip planned. What to do? What to do?