Question about CPap machine

[CharlieS3]

I've been on CPAP for 20 years now and at a pretty high pressure of 14. I've camped for years in my RV using the Resmed DC adapter. I found some 12 volt wiring under the bed that runs the slideout and tied a 12 Volt DC outlet into that. I have a huge set of batteries and about 860 watts of Solar, and I've never run into an issue. We almost always dry camp without any other power hookups. I've gone over two months without hooking up to power.

My CPAP does not power up the humidifier when on DC power. I just put water in the reservoir and live with the passive humidifier. Not ideal, but OK.

The key to this is solar. It is easy to set up a small system for this purpose. As mentioned earlier, a couple of the larger jump boxes (for car starting) will probably get you through a week of camping.

[Skocan]

I have a newer machine (Philips) were I can remove the humidifier. I received an automotive booster pack for Christmas and decided to try it out with the 12v cord made for the machine. 67 hours of sleep before I had to recharge the pack. And buckets less expensive than the "made for" battery pack solutions. Also found not having the humidifier not an issue.

[jacques1543]

This is only an issue if you boondock! But thanks for asking this question as we are about to leave on a long trip with some Boondocking involved and we both use clap machines ! Now I know I will run the generator!

[Delco Bobby]

Those of you who use auto booster packs, can you tell us which brands and models?

How old are your machines?

I bought a booster pack awhile ago but when the time came it only lit up the display, no fan or pressure.

Then I tried running off of an inverted outlet. That was good for a couple of hours. Then a low voltage alarm from the inverter woke me up. After that I fired up the generator and had a great nights sleep.

So which modern lithium boosters will work?

I have two machines. An about 8 year old Philips Resprionics REMstar that I use for travel.

A one year old Philips Resprionics Dream station. I don’t need or use the humidifiers.

[frankraney]

Originally Posted by RockyRed

How to you power your cpap machine? I hear that if you run the humidifier part it draws a lot from battery. Any thoughts on how to deal with this ?

You have two options. Run the vehicle to charge the battery, or get a generator. I got a gen, they are cheap at harbor freight and calling world. Actually 3 options......you could add solar and another battery or two.

[Alben]

I am surprised how many people here say their CPAP is 24V. I am an electrical engineer, so here is my take on using an inverter: Most 12VDC to 110VAC inverters are about 80-85% efficient. Then the 110VAC to DC brick adapter supplied with the CPAP itself is an 80% efficiency rating. In other words, using an inverter in combination of the factory DC brick of the CPAP, you are probably losing about 40-45% of your available battery power with the two conversions. This is significant, almost 1/2 of your battery life is wasted.

My CPAP is able to run on 12VDC directly with a cigarette lighter to 12VDC barrel plug cord. This makes it the most efficient use of battery power, as there are no power conversions. My camper originally did not have a 12VDC plug by my bed, so I put one in. The humidifier consumes a lot of current, so I don't use the humidifier when camping. In the summer I seldom need the humidifier anyway.

When shopping for a new CPAP, make sure it can run on 12VDC.

I took some measurements of my CPAP running.
Philips Respironics REMstar 50 series Auto 550P
CPAP not running 100mA (plugged in, not running)
CPAP free running 2.2 Amp (mask not on face, free running)
CPAP in use breathing 0.5 Amp (mask on face, breathing normally)

Here is how long you could run such a CPAP if there were no other drain on the battery: Group 24 marine battery is about 65 AmpHour with about 32 AmpHour useable (50% discharge). 32 AmpHour / 0.5 Amps = 64 Hours of continuous run time. In other words 7 nights of usage.

Obviously, the battery is used for other things, but you get an idea of the demands of a CPAP running directly on 12VDC with no humidifier.

[Oldmanjam]

I use a Phillips Respironics Dream Machine which operates on 12VDC (through a converter when on AC). I purchased the 12V cord for the CPAP and plug it into a Harbor Freight Power Pack Jump Starter (https://www.harborfreight.com/3-in-1...ter-62306.html), purchased for $60 USD, which has a 18 AHr lead acid battery. I turn off the humidifier on the CPAP but leave it attached with water in it. The Power Pack will easily run the CPAP this way for 2 nights. I recharge the Power Pack with a male-male 12V cord with one end in the Power Pack and the other in a 12V receptacle on the dash of the RV when driving or recharge for 1 hour on the generator (same 12V connections because house and chassis batteries are connected when 120VAC present)

[ZampSolar]

This is a great topic. Thanks for asking. I'll try to be as concise as possible. Zamp Solar started due to the use of a CPAP machine, dead batteries and local camp neighbors angry over constant generator noise.

We'd like to say that solar is the perfect option, but there are a few different ways to accomplish powering a CPAP machine through the night or through several nights.

Our Recommendation -
From what we see with average RV'ers, we recommend CPAP users get a battery bank of about 225 to 300 amp-hours and at least a 200-watt solar system for most RV's 25' and smaller. Larger RV's should look for a 320 watt or larger system. Average campers boondock for 3-4 days at a time, and uses other devices in the RV (TV, Lights, H20 Pumps, Fans).

Why we recommend it -
CPAPs can have two main functions, pressure and humidifier. The pressure is needed to create positive pressure for the airway to open up, the humidifier helps to wet the air so you don't feel like you were just sucking on sandpaper all night. They both use power to work. But pressure can be used without the humidifier. Each pressure and humidifier have a range of setting. The doc will usually set the pressure, but the humidifier can be used or not used at all. Personal choice as to what setting it's on.

CPAPs can work off 110VAC outlets (wall power, much like a house), or 12VDC (battery power). Most CPAPs today have a 12VDC adapter as an option for powering their device. Some older models do not have this option. This is important as the older models will require an inverter (converts battery power to house power), and inverters will increase the amount of power used. Using it on a 12VDC also loses power, but it generally minimal loss. If an inverter is needed, use a pure sine wave inverter with your machine - see note below. You can expect about a 1.1% loss with this type of inverter.

Generally, we see CPAP machines CAN use up to 100 watts of power. This is generally when the pressure and the humidifier are at max. At any other lower setting the power consumption will be less. On average we find that CPAP machines use between 50 and 80 watts. 50 watts if the pressure is the only thing on and 80 for common pressure and humidifier settings. This equates to between 30 and 60 amp-hours a night. We like to use amp-hours due to battery capacity ratings.

Powering Using RV Batteries and Solar-
In an RV, when using lead acid batteries (WET, GEL, AGM, CAL) plan to size the battery bank to 3 to 4 times larger than the average daily draw. Sizing a battery this way will help keep your battery lasting much longer than average. Using lithium tech batteries plan on sizing the battery bank 1.5 times more than daily draw. Daily draw has to be calculated differently for everyone. But I hope the figures above can help calculate average daily draw. Feel free to contact us and chat about what your potential might be. Using a proper solar system and never allowing the battery to go down past 50% one can expect their batteries to last 3 to 4 time longer than average. It also helps to have a larger bank due to poor weather and lack of decent power. This way the bank can be used for 2 full days before it's at 50% and most of the time, with good sun, only 25% is used.

For example - 200-watts and 6 hours of good sun (good average for most locations) on average expect about 60 to 70 amp-hours of recharge power. This should take care of most CPAP machines only, not including other draws on the system. Larger RV's generally use more or people using larger devices or devices for long periods of time should size accordingly. If only the pressure is used on the machine consider ~150-watts.

Powering on Battery Only -
If planning to use a battery only I'd suggest getting a separate lithium CPAP battery bank. Most CPAP lithium batteries can last for a few days and can last for years. I don't suggest using the RV battery bank only unless the batteries are only drawn down to 50%. Killing a lead acid battery several times will result in battery replacements every 1 to 2 years. Very expensive.

Powering Using a Generator -
If planning to power a CPAP with only a generator, sizing the battery bank is important so money isn't wasted on expensive battery replacements. When using LEAD ACID batteries, plan to not deplete the batteries past 50% per night. When using lithium batteries this is not a concern, just make sure there is enough power to power the RV and CPAP for the night. It also helps to make sure the RV has a smart converter for battery charging off of a generator or shore power - get a three stage high amp charger. Stay away from simple trickle chargers.

Inverter Note -
There are two main types of inverters. Modified and Pure Sine wave. Modified is a dirty signal and should be avoided when using a CPAP machine. It's less efficient and makes the CPAP work harder and can potentially make the machine fail quicker. Modified can also have a higher efficiency loss, we don't work with them so I cannot comment on the loss. Just get a pure sine wave for your sensitive electronics.

Zamp Solar
Techs - Joe/Jeff

[Kaffeenjunkie]

Originally Posted by cavie

Go see your Cpap doctor. I have a full beard and used a full face mask for years. they had to turn up my pressures. After that, I could not stand it. I know wear a new style just nose piece. Not even a nose mask. It's a little larger than a typical oxygen nose piece but nothing goes in the nose. It's called Dreamware. Don't mess with pressure and humidity settings unless you know what you're doing. If they aren't right your wasting your time using the machine.

https://www.easybreathe.com/DreamWea...RoCetEQAvD_BwE

Same here- Love, love the dreamware. I hated the cpap when I first got it. My doc did an in-home sleep diagnostic. The tech set it so high I couldn’t breathe, it was so forceful I couldn’t breathe out. I finally was referred to a real sleep center and did an overnight there. They dialed in and adjusted the machine for me, My wife and I sleep 8 hours blissfully.
I do not use the humidifier at all. Makes me feel like I am drowning.

[SlowrideHD]

My wife uses a CPAP. My battery bank in our 5th wheel is two EverStart Deep Cycle batteries, p/n 29DC that each are rated 122 amp hours. They are hooked in parallel so I have 12v with 244 amp hour capacity. I have an AIMS 600 watt pure sine wave inverter hooked to the battery bank and have installed a 120v receptacle in the floor of our bedroom right beside the bed. Easy for her to plug in her CPAP and we know that that floor receptacle is from the inverter only.
We also have a Honda 2000i generator if we need it.

[jaherbst]

For what its worth. I have 400 solar, 1500 inverter, two inline batteries. With fridge on gas (12v fan runs) and two CPAP with humidifier my batteries are dead in the AM. I turn off inverter at night because Fridge will run on it (115)

I leave the inverter off until need for temporary use then turn it off. If not plugged in I will run the Generator for using CPAPs. Dealer also uses CPAPs and had them disconnect the Inverter to the Bedroom outlets.

We both need the humidifier here in the SW. IMHP inverters were never designed for constant use. only temporary. i.e. Microwave etc.

Jack

[rk06382]

Originally Posted by Kaffeenjunkie

Same here- Love, love the dreamware. I hated the cpap when I first got it. My doc did an in-home sleep diagnostic. The tech set it so high I couldn’t breathe, it was so forceful I couldn’t breathe out. I finally was referred to a real sleep center and did an overnight there. They dialed in and adjusted the machine for me, My wife and I sleep 8 hours blissfully.
I do not use the humidifier at all. Makes me feel like I am drowning.

I had earaches with the high CPAP air pressure and the Doctor switched me to Auto CPAP. The pressure starts at 8 and only increases if I need it. I have tried four different nasal masks over the past four years. I have been on the DreamWear Gel Pillow for a year. I tried the standard DreamWear cushion but it leaked because of my deviated septum.

I like the DreamWear Gel Pillow because I can talk to my wife while on the CPAP. With the DreamWear the hose is the top of your head and not around your neck. I can sleep on either side or back as long as I do no blow air on my wife. I use a CPAP Retracting Reel to manage the hose. I use the humidifier and a heated hose. I cover the hose with a CPAP SnuggleHose Cover. The heated hose keeps water from condensating in the hose and drowning the mask with water.

I left my CPAP plugged into a Kill A Watt Electricity Usage Monitor all winter. The average nightly power used was 760wh or 63ah@12v. That was with a humidifier and a heated hose.

[Skyliner]

Originally Posted by jaherbst

For what its worth. I have 400 solar, 1500 inverter, two inline batteries. With fridge on gas (12v fan runs) and two CPAP with humidifier my batteries are dead in the AM. I turn off inverter at night because Fridge will run on it (115)

I leave the inverter off until need for temporary use then turn it off. If not plugged in I will run the Generator for using CPAPs. Dealer also uses CPAPs and had them disconnect the Inverter to the Bedroom outlets.

We both need the humidifier here in the SW. IMHP inverters were never designed for constant use. only temporary. i.e. Microwave etc.

Jack

Jack, you give capacity of solar, capacity of inverter, but omitted capacity of your batteries bank.

Not sure if you are saying your CPAP are run off of inverter power? Every RV fridge I've seen except compressor residential ones can run off of propane without needing inverter 120 volts AC power.

Please elaborate when you mean by the dealer's CPAP. Not sure I understand what your mean by your statement. Thanks!

[wwachsman]

I bought a sine wave inverter and dont use the heater for the water. In the morning still have the most of a single battery.

[jaherbst]

Originally Posted by Skyliner

Jack, you give capacity of solar, capacity of inverter, but omitted capacity of your batteries bank.

Not sure if you are saying your CPAP are run off of inverter power? Every RV fridge I've seen except compressor residential ones can run off of propane without needing inverter 120 volts AC power.

Please elaborate when you mean by the dealer's CPAP. Not sure I understand what your mean by your statement. Thanks!

Sorry I was not very clear on this. Both batteries are deep cycle marine/RV batteries. They were installed new when I purchased the new toy hauler in Jan 2018. Not parked at the house and in my hanger so cannot give the exact Amps of the batteries.

At PDF owner of dealership said he uses a CPAP also and recommended disconnecting inverter from the bedroom ac outlets which was done. Both my wife and I use a CPAP.

My inverter is connected to my refrigerator which will run it on 115 AC and run the batteries down in about 5-6 hours if not manually connected to gas. I have never had an inverter connected to the fridge before. My Fridge is a three way automatic connect i. e. 115 VAC priority from Generator or shore power, next priority is 115 VAC from Inverter/battery and last priority is gas in that order. If no 115 VAC from Generator or Shore Power it is powered from Batteries via Inverter. (115 VAC)

I now keep inverter off to prevent it from powering the Fridge. With Inverter off it will automatically revert to Gas with batteries running the small electric fan on the fridge.

I only use the inverter when needed such as Microwave etc. and make sure it is off so as not to power the Fridge with 115 VAC via the batteries automatically when not plugged into shore power or have Generator running.

I know this is confusing but leaving the inverter off until needed and shutting it off after use solves the problem. I have discussed this with the dealer and the factory in Hemet CA and could permanently disconnect the inverter from the fridge altogether but leaving the inverter off until temporary use and then making sure it is off after use solves the problem. All trailers coming out of the factory with an inverter now are wired that way. I would imagine it is in case you run out of propane the batteries will keep the fridge cold temporarily. (5-6 hrs.)


Of the seven motorhomes I have had with an inverter non ever powered the Fridge with loss of normal 115 VAC when inverter was on.

Jack

[pmsherman]

Originally Posted by rk06382

You should get a Kill A Watt EZ Electricity Usage Monitor to find out how much electricity you will need. I did and I only needed 6.5ah to run my CPAP for the night. That is with the Heated Tank & Hose.

Amazon: Kill A Watt EZ Electricity Usage Monitor

I have one of these meters. The 500W I measured came from that meter. The DW's CPAP machine uses around 120W a night, including the humidifier heater.

My big issue is the power my medical equipment requires. It has, according to the manufacturer, AC motors in it that won't work on a MSW inverter. It also has a very loud alarm, run from an internal battery that goes off if AC power disappears during use. The alarm is loud enough in an rv to wake the dead and should wake up anyone in a nearby rig. I discovered this last Fall when I discovered that my converter, when outputting lots of amps to charge the battery, would trip a GFCI outlet feeding power to the rig. I installed my spare converter (different manufacturer) and had no problems with the GFCI after that.

Between both medical devices, I need to plan on needing 650W of power for them. With conversion losses at the inverter, this comes out to 55-60A. With a 220A battery bank and a "use only 50% of capacity" rule, that's over half of the bank's usable capacity. This doesn't leave enough capacity to boondock in the Winter when I need a significant amount of power for the furnace fan. I should be able to do Summer and Fall single night boondocking as long as I can recharge the batteries the following day.

My new PSW inverter is located inside a kitchen cabinet, close to the house batteries. It presently feeds an outlet in the cabinet and the fridge 120V outlet. The rewiring for the fridge outlet was done by my dealer when I bought the rig and had the MSW inverter installed. The wiring done by the dealer was fairly simple because all of it was behind the cabinets on that side of the rig. To get all of the outlets powered by the inverter, I'll need to run a new line from the breaker box to the inverter, an interesting job since it needs to cross from one side of the rig to the other.

Phil

[rk06382]

Originally Posted by pmsherman

I have one of these meters. The 500W I measured came from that meter. The DW's CPAP machine uses around 120W a night, including the humidifier heater.

My big issue is the power my medical equipment requires. It has, according to the manufacturer, AC motors in it that won't work on a MSW inverter. It also has a very loud alarm, run from an internal battery that goes off if AC power disappears during use. The alarm is loud enough in an rv to wake the dead and should wake up anyone in a nearby rig. I discovered this last Fall when I discovered that my converter, when outputting lots of amps to charge the battery, would trip a GFCI outlet feeding power to the rig. I installed my spare converter (different manufacturer) and had no problems with the GFCI after that.

Between both medical devices, I need to plan on needing 650W of power for them. With conversion losses at the inverter, this comes out to 55-60A. With a 220A battery bank and a "use only 50% of capacity" rule, that's over half of the bank's usable capacity. This doesn't leave enough capacity to boondock in the Winter when I need a significant amount of power for the furnace fan. I should be able to do Summer and Fall single night boondocking as long as I can recharge the batteries the following day.

My new PSW inverter is located inside a kitchen cabinet, close to the house batteries. It presently feeds an outlet in the cabinet and the fridge 120V outlet. The rewiring for the fridge outlet was done by my dealer when I bought the rig and had the MSW inverter installed. The wiring done by the dealer was fairly simple because all of it was behind the cabinets on that side of the rig. To get all of the outlets powered by the inverter, I'll need to run a new line from the breaker box to the inverter, an interesting job since it needs to cross from one side of the rig to the other.

Phil

I just install my new Samlex 2200 Watt PSW Inverter/Charger.
see: Expanding compartment space for 2200 Watt Inverter/Charger

I designed the system but age & heath required that I hire a RV shop to install. Cache Camper Manufacturing, Inc builds custom campers for Alaska.

I was going to double my batteries with four new Interstate batteries. Then I found out Battle Born Batteries would ship to Alaska. They also gave me a Military discount. I did the total cost of ownership of Lead-Acid vs LiFePO4 batteries. I now have four 100Ah 12V LiFePO4 Battle Born Batteries.

I then had Cache Camper install six 100 watt of solar panels. I now have a complete system:
1> 2200 watt Samlex PSW Inverter/Charger. I have enough power for the microwave.

2> 400ah - four 100ah LiFePO4 deep cycle lithium batteries. LiFePO4 can be discharged 100% vs lead acid recommended 50% depth of discharge.

3> 600 watt of Solar Panels with a 40 amp MPPT charge controller. I was getting 65 watts from the solar panels in the rain.

I am still testing the system in my driveway while work on installing a few 12v DC outlets and other modifications.

I found I need to design ventilation for the Inverter/Charger. I programed EVO-2212 to charge the LiFePO4 batteries at 100 amps. LiFePO4 batteries can be charged at 50% of 100ah rating. 400ah can be charged at 200 amps. Lead-acid is about 25%. I can recharge in a few hours on shore or generator. A 100 amp charger does produce heat. I will vent it to the battery bay. I am already planning to have Cache Camper sealing the battery bay and add space for more LiFePO4 batteries.

I still need to order a Victron BMV-712 Battery Monitor.

I will get back 30% of the total cost of this project with Federal Tax Credit for Solar.
See thread: If your considering Solar now might be the time

[Skyliner]

RK06382,
Sounds like you have an awesome system. Please let us know what your experiences are with the samlex inverter/charger. My next camper will have an inverter/charger for reduced complexity. Hopefully by then Lithium batteries will have

[Tom48]

Originally Posted by wwachsman

I bought a sine wave inverter and dont use the heater for the water. In the morning still have the most of a single battery.

When I first had cpap in old trailer I had one separate agm battery under the bed to run it. With low temp on humidifier battery ran for two nights, although not full nights because I only tolerate the darn thing for about five hours in a night.

I soon hooked the agm up to the coach wet batteries (I know. Not supposed to mix battery types.) and coach solar then when all three batteries were charged I isolated the agm with a switch to keep it as back up when running inverter or 12 v cpap. From that day forward, including intermittent use of 2000 PSW inverter, the solar always topped the batteries enough to meet all of our needs, including the cpap.

The problems I read in here made me think the author ran frig and cpap on inverter and just didn't have enough battery for that. Both of my CPAPs run fine directly on 12vdc. And I've seen others that would need a voltage buck device, but could be made to run on DC voltage. And we NEVER RUN our propane/120v frig on the inverter. On gas it uses only a tiny bit of battery/12vdc. On inverter provided 120vac, it sucks way too much battery for even a good two battery system.

[Stotes57]

Another option, that I use when traveling, is provent. These are little self-adhesive devices that you put over your nostrils. You can still breath in normally, but there is added resistance when you exhale to keep the airway open. DW claims they do the trick - she gets a good night's sleep.
The only issue is cost - $2-3/night.

https://www.proventtherapy.com/