BajaNomad - Small pure wave invertor for CPAP machine?

Small pure wave invertor for CPAP machine?

Santiago - 6-27-2021 at 03:36 PM

I want to take my CPAP machine on a 2 night camping trip with the grand kids but I need a small pure sine wave invertor. I also don't want it to be noisy either.
Any recommendations?

Unit's power supply is a 90W unit
Typical Power Consumption: 53W (57VA)
Peak Power Consumption: 104W (108VA)
If I did my math right, a 105 amp deep cycle should get me through 2 nights at 7 hours each? What I don't know is how much is lost inverting.

SFandH - 6-27-2021 at 03:52 PM

Inverter specs will tell you how many amps they consume doing their magic. Not much. Check out Amazon.

A smallish inverter will be noisier because its cooling fan will kick in when it's working hard. Consider a 2000 watt inverter, you'll be able to use it for other things too.

Bob and Susan - 6-27-2021 at 04:36 PM

you are camping...leave the CPAP machine HOME!!!
"come on man"

BajaBlanca - 6-27-2021 at 07:37 PM

No can leave home. I know from Les who could not even sleep on our overnight plane trip. Terrible.

[Edited on 6-28-2021 by BajaBlanca]

bent-rim - 6-27-2021 at 08:24 PM

I have a Jackery 1000w Solar Generator. It puts out a pure sine wave. I can charge it using 12v, 110v or solar panels.

http://www.jackery.com

[Edited on 6-28-2021 by bent-rim]

mtgoat666 - 6-27-2021 at 08:27 PM

Quote: Originally posted by Santiago

I want to take my CPAP machine on a 2 night camping trip with the grand kids but I need a small pure sine wave invertor. I also don't want it to be noisy either.
Any recommendations?

Unit's power supply is a 90W unit
Typical Power Consumption: 53W (57VA)
Peak Power Consumption: 104W (108VA)
If I did my math right, a 105 amp deep cycle should get me through 2 nights at 7 hours each? What I don't know is how much is lost inverting.

I don’t need/use a cpap, but I have seen a number of people camping using the battery-powered travel cpaps. I understand they hold enough charge for 2 nights, so just need recharging every other day.
I think using one of the travel units sounds easier than what you are trying to macgyver.

motoged - 6-28-2021 at 12:40 AM

Quote: Originally posted by Bob and Susan

you are camping...leave the CPAP machine HOME!!!
"come on man"

Appears you don't have sleep apnea. They are medical devices, not a down comforter.

I bought a transformer unit for about $200 from cpap outlet and hook it up to portable car battery I carry when truck camping. I get 4 nights use so far even with humidifier attached

[Edited on 6-28-2021 by motoged]

[Edited on 6-28-2021 by motoged]

Santiago - 6-28-2021 at 05:07 AM

Quote: Originally posted by motoged

Quote: Originally posted by Bob and Susan

you are camping...leave the CPAP machine HOME!!!
"come on man"

I'll check that out. Thanks.

Russ - 6-28-2021 at 06:15 AM

search youtube - "cpap moble power" a lot of info.
https://www.youtube.com/watch?v=mCw2HqcuhDw

[Edited on 6-28-2021 by Russ]

Timinator - 6-28-2021 at 07:51 AM

I've had my buddies use their CPAP machines on my modified sign-wave inverter with no problems. Are you sure you need a pure sine-wave?

Bob and Susan - 6-28-2021 at 09:41 AM

you know i grew up in the 50's 60's and 70's...
an adult in the 80's and 90's and there were NO CPAP machines

how did people sleep?
how did we go camopping?

well...as i remember it...you worked hard...
got tired...and fell asleep

the medical industry found a "cash cow" with the CPAP machine

motoged - 6-28-2021 at 11:43 AM

Geez, now we have obstructive sleep apnea deniers..... :rolleyes:

AKgringo - 6-28-2021 at 12:12 PM

I have experienced the signs, and symptoms of obstructive sleep apnea most of my life! It was not officially diagnosed until eight or ten years ago, when my cardiologist signed me up for a sleep study.

The first night was an observation and measurement exercise that recorded the frequency and intensity of the events. I was at the low end of the spectrum for health concerns, but I returned the next night to repeat the study with a cpap device.

I could not tolerate the procedure well, and long before the night was over, the study was ended and I went home to get some sleep.

The one thing I would like to add to this conversation, is that the frequency and intensity of my episodes, appear to be directly related to the frequency and quantity of alcohol consumed.

cpap battery or invertor?

akshadow - 6-28-2021 at 12:28 PM

depending on brand some will work directly on 12 volt power or have a decicated battery available (usually without heated moisture) typically direct 12 volt will be most efficient. brand provided battery next.

geraldalexander7 - 6-28-2021 at 12:35 PM

Quote: Originally posted by Bob and Susan

you know i grew up in the 50's 60's and 70's...
an adult in the 80's and 90's and there were NO CPAP machines

how did people sleep?
how did we go camopping?

well...as i remember it...you worked hard...
got tired...and fell asleep

the medical industry found a "cash cow" with the CPAP machine

Bob and Susan
No need for you to continue to post about this subject, you are uninformed. Those that have had their quality of life improved by CPAP(myself included) do not welcome your comments.

mtgoat666 - 6-28-2021 at 12:52 PM

Quote: Originally posted by Bob and Susan

And just perhaps you have sleep apnea and the nightly sleep/oxygen deprivation has affected your brain and made you think/say cuckoo things, eh?

willardguy - 6-28-2021 at 01:19 PM

been awhile since we've had a good "Bobism" :rolleyes:

....the light in that lighthouse is getting dimmer and dimmer

SFandH - 6-28-2021 at 01:42 PM

IMHO Santiago is correct to want a pure sine wave inverter. Electric motors run more efficently. I'm assuming CPAP machines have electric motors, I don't know for sure.

"Modified Sine Wave (quasi-sine) A modified sine wave inverter actually has a waveform more like a square wave, but with an extra step. A modified sine wave inverter will work fine with most equipment, although the efficiency or power of the equipment will be reduced with some.

Motors, such as refrigerator motor, pumps, fans etc will use more power from the inverter due to lower efficiency. Most motors will use about 20% more power. This is because a fair percentage of a modified sine wave is higher frequencies – that is, not 60 Hz – so the motors cannot use it."

https://theinverterstore.com/faq-items/what-is-the-differenc...

I know my little shop-vac hates my modified SW 1000W inverter. The motor runs HOT and at slower RPM.

Bob and Susan - 6-28-2021 at 01:46 PM

remember all you nite time "maskers"...
clean those things daily or you'll be "sucking mold"

i'm still amazed at how many people use a CPAP
they draw very little current but make noise

how does the person next to you sleep?

im just saying that for 2 days "camping" you could leave a CPAP home

AKgringo - 6-28-2021 at 02:13 PM

I do not use a cpap, but I can gaurantee that you would rather listen to that, than my horrendous snoring! I don't know this for a fact, but don't the cpaps cut down on snoring?

[Edited on 6-28-2021 by AKgringo]

JZ - 6-28-2021 at 02:58 PM

There definitely seems to be an over use of CPAPs in America.

Can't believe everyone needs one. A bit of a crutch factor going on.

elgatoloco - 6-28-2021 at 03:16 PM

[/rquote]

Definitely an overuse of prescription drugs for people with so called depression especially kids who had to stay home last year.............a bit of a crutch factor. Just saying. :rolleyes:

*I don't use cpap and I don't need antidepressants. yet.

This we me making an inane comment about something I have no practical experience with and it makes me look like an ass, does it not? we can all agree that I (we all) would be better served if I was to have kept my mouth shut about something I not little to nothing about rather then open it and sound like a fool. :saint:

* I did do a sleep study at Scripps in 2019 with my wife in the interest of marital harmony. Turned out I scored slightly better and just under the threshold for needing a cpap. In the last 18 months I have lost about 20 pounds and am more quiet in my sleep. If you know what I mean. :biggrin:

Better living thru chemistry. And science.

[Edited on 6-28-2021 by elgatoloco]

Bajabus - 6-28-2021 at 04:04 PM

There is no such thing as a pure sine wave inverter. That statement is a marketing gimmick. The only way to produce a 60hz pure sine wave is to spin an armature inside a stator at 60 revolutions per second.
All inverters produce a stepped waveform. The difference between a cheap inverter and a nice inverter is the number of steps in that waveform and the filtering reactors it has. The really nice inverters have the ability to increase or decrease the number of steps depending on the load. The greater the load the more steps produced. The 1st inverter able to do that and available to the public was the super sweet Trace 2500 back in the late 80s, I wish they still made that puppy. The higher switching rates coupled with new PWM (pulse width modulation) schemes to create those tiny steps introduce high frequency noise so the nice inverters have those filtering reactors but they tend to be heavy. I have seen tremendous changes and improvements over the years. Today I install maintain and service 3 phase inverters producing up to 6MW with 1500 VDC inputs and 690 VAC outputs. We step that up to 36,000 VAC and feed it into the grid. When looking for a good inverter that uses the marketing term "pure sine wave" You want to look at the total harmonic distortion. Ideally it should be 3% or less, 5 is tolerable but above that is crap. Most inexpensive "pure sine wave"inverters will not tell you this number they typically say something like "lower" THD

All of this to say that this $34 300 watt inverter should suit you fine.
https://www.amazon.com/BESTEK-300Watt-Inverter-Converter-Cha... I have two and they have served me well in all manner of instances. I don't know the THD on it but it produces so little noise i can even run my O-Scope on it which is pretty sensitive to noise.
Good luck with the sleep apnea. Modern medical discovery's and improvements should be welcome. I wear a small continuous glucose monitor that lets me see my sugar levels on my watch and a tiny pod that delivers insulin that I can easily adjust to customize my insulin delivery. These devices have vastly improved my quality of life. Should I not bring them camping because real men in the 60's out in the boonies sucked it up and went comatose. ***k that.

[Edited on 28-6-2021 by Bajabus]

[Edited on 29-6-2021 by Bajabus]

What is wrong with some of you people?

Howard - 6-28-2021 at 04:10 PM

For crying out loud, what if it extended your life and better living through modern inventions? Why do you think the average age for the living has gone up and up over the decades/centuries? Is it just a coincidence that medicines and machinery have improved the quality of life? I think not, it's no coincidence.

Your right, all users don't need a C-Pap and most probably do not need one to survive. The same case can be made for most medical inventions. However if it improves your quality of life and extends your quality of life, why not?

Your right, society uses way to many things as a crutch as we are a lazy bunch of humans and looking for the easy way out. Why condemn the people who actually benefit through modern science?

Bajabus - 6-28-2021 at 04:14 PM

Here I am with a 3.3 MW inverter in Utah's beautiful Milford valley

elgatoloco - 6-28-2021 at 04:31 PM

[/rquote]

Definitely an overuse of prescription drugs for people with so called depression especially kids who had to stay home last year.............a bit of a crutch factor. Just saying. :rolleyes:

Better living thru chemistry. And science.

[Edited on 6-28-2021 by elgatoloco]

willardguy - 6-28-2021 at 06:11 PM

Quote: Originally posted by JZ

There definitely seems to be an over use of CPAPs in America.

Can't believe everyone needs one. A bit of a crutch factor going on.

what a joke! lets talk a little about the "crutch factor" this from the self proclaimed "one of the top offroad GPS experts in the world" thats a quote. here's a guy that obviously needs GPS to find his way from san diego to the coral hotel! now this azzhole is gonna school us on CPAP machines??
gimme a break! :rolleyes:

willardguy - 6-28-2021 at 08:12 PM

Bucks crutch is the internet forum

Alm - 7-1-2021 at 09:14 PM

Quote: Originally posted by Santiago

Unit's power supply is a 90W unit
Typical Power Consumption: 53W (57VA)
Peak Power Consumption: 104W (108VA)
If I did my math right, a 105 amp deep cycle should get me through 2 nights at 7 hours each? What I don't know is how much is lost inverting.

You'll be fine with inverter rated 120W continuous power. Samlex is a decent brand: https://www.amazon.com/Samlex-PST-120-12-Pure-Inverter-Watts...

If you rely on specs, not measurements, they might say 104W for starting the motor, and then it turns out to be 150W. Maybe get
300W unit: https://www.amazon.com/Samlex-America-PST-300-12-Pure-Invert....

You don't need a bigger inverter if all you have is 105 AH battery.

Inverter losses can be 5-15%.

53W non-stop is 33 AH per 7 hours with inverter losses. Your battery should better be fully charged before the trip.

landyacht318 - 7-2-2021 at 10:47 PM

Does the C pap have a power brick?

If so, it will list an output DC voltage and amperage. Multiply output voltage times output amperage and than will give the maximum wattage the power brickis rated to output continuously( in a lab), which can be different that what the C pap draws at any given time.

Powering a Cpap often comes up on RV related forums. The solution for those who don't already have an inverter, and more than enough a battery capacity to power it, is the DC to DC converter, instead of using an inverter taking 12vdc, changing it to 115vac, only to have the powerbrick convert 115 vac to whatever DC voltage the Cpap uses.

Some cPaps have the 'car adapters' as as option. Please note that the ciggy plugs and 12v powerport/ ciggy plug receptacles and the wiring leading to those receptacles is often super substandard. This ciggy plug/12v powerport connection, even when all is as good as it can be, is still substandard and can work its way loose all too easily, and the more often it is asked to pass 50+ watts the more likely this is to occur, sooner.

a 2000 inverter powering a 53 watt load will be much less efficient than a 200 watt inverter powering the same load, and most inverters say they are upto 85% efficient, but consider there to be a huge asterix with that statement which make it rarely attained.

a 2000 watt inverter turned on, yet powering nothing will draw ~ 20 watts, whereas a 200 watt inverter turned on, powering nothing will draw 3 to 6 watts from the battery. Not so much a factor in C pap usage unless one forgets to turn off the inverter after they wake up.

If one Knows the DC voltage the C pap is expecting to see, and it is not already in the 11.5 to 13.5 vDC range, then one can get a DC to DC boost/ step up converter and wire it up themselves, if they have some wiring skills and the desire to do so. 150 watt versions of Boost/ step up converters can be had, slow boat from China, for as little as 3$, or 7$ from a US vendor.

I bought one and it works well, and has exceeded that 150 watt rating for far longer than ever intended, but I did install a 50mm fan atop the heatsinks.

If the output voltage is less than 12vDC, then one gets a step down, buck converter, and these visually appear almost identical to the step up/ boost converters.

There also exist step up/ step down, buck boost converters available, in several different wattage ratings but these are less efficient than a simple buck or boost only converter.

The inverter is often seen as the solution to all problems, but their inefficiency, and noise, often can cause issues, especially when the charging capability is not upto snuff, or the battery capacity and its remaining health are questionable/unknown.

Seek a premade DC to DC 'car adapter' or similar for your Cpap, if the ONLY thing you need an inverter for, is the Cpap.

Having an inverter for other things is of course useful, but don't expect to be powering a hair drier, and 'Pure' sine wave vs modified square wave can be an argument with no end, as to what actually needs 'pure', vs which is 'just fine' with modified.

If you have some DIY skills and inclinations, then feeding the Cpap the required DC voltage is relatively easily accomplished.

Here is the first DC to DC step up boost converter that I found a link to.

https://www.amazon.com/Converter-Yeeco-Voltage-Regulator-Adj...

Note these claim to be upto 95% efficient, whereas most inverters claim upto 85%, and that does not include the inefficiency of the powerbrick which came with the Cpap, which can be in the 80 to 85% range.

I mounted my 150 watt/ step up converter in an old ventilated gutted power supply transformer based power brick and modified it with a larger fingertwist potentiometer voltage dial and voltmeter on it to easily change output voltage. some of them have a voltage potentiometer, as well as a current limiting potentiometer as well, but the latter is unneeded for a cpap application. There are also some that come with input and output voltage displays and buttons to change parameters and clear enclosures for not all that much more money.

I've found the smaller sub 60 watt boost or buck converters with the current limiting potentiometer to be less reliable than the voltage only adjustment, but have had no issues with the 150 watt versions.

A PWR+ branded DC to DC 'car adapter' is powering this '90 watt' laptop, as I type this, and I got it over 10 years ago.

It is drawing on average, 32 watts, but if I use the original powerbrick, on my inverter, the laptop through tine inverter consumes an average of 47 watts, and I have to listen to the dang inverter fan. My powerbrick might run slightly hotter on my MSW inverter compared to when my PSW inverter still worked.( wagan elite 400 watt PSW, avoid!)

I make extensive use of voltage buckers as speed controllers for powerful 12vDC fans, and as insanely bright LED dimmers, and in cases of 24vDC fans, buck/boost converters. The main issues are that I wear out the cheap potentiometers and need to replace them every 2.5 years or so, though some Caig Deoxit f5 fader Lube is often the cure, without replacement.

Anything which draws more than 25 watts, I do not use ciggy plugs, but cut them off and use Anderson powerpoles instead.
Usually upto 50 watts is OK with ciggy plugs/ receptacles, but failure is just a matter of time with such a poorly engineered, but ubiquitous, electrical connector.

My 45 amp Anderson powerpoles have no issues passing 55 amps continuous, but I am shoehorning 8AWG into contacts which say 10AWG max.

Anderson Powerpoles are great connectors, but not perfect.

Use binder clips over their ends, to prevent ruining them when inevitably treating them like one does their 115 vAC connectors

Santiago - 7-4-2021 at 05:32 AM

Turns out Resmed makes a DC brick, see here. I've ordered it and we will see. Thanks for the huge amount of info.

GeraldoS - 7-5-2021 at 02:16 PM

Every CPAP I have seen runs on 12v to 24v DC. The plug has a black box on it which is a transformer to step the voltage down from 120-240AC down to 12-24 volts and then a rectifier to convert the AC to DC. So, it does not matter how the sine wave looks on the AC side. It comes out as pure DC on the other side which feeds the CPAP.