Energy Can't figure out how to run CPAP off grid, long term

Discussion in 'Off Grid Living' started by jpek, Jun 16, 2020.

  1. jpek

    jpek Monkey

    Hello, everyone. I'm new to the forum. I need help with a certain prepping matter that I've been wracking my brain about and unable to solve. I am a CPAP user (used to treat sleep apnea). One of my major concerns in any extensive power outage is that I won't be able to power my CPAP, therefore won't be able to get good sleep, maybe for many nights in a row. Therefore I'll spend my day in a fuzzy, spaced out state, which is the last thing I want to be dealing with in an emergency situation. So, it's been a priority for me to try to figure out how to at least get my CPAP off grid.[*] As an added bonus, I'd like to be able to go camping sometime.

    The CPAP uses an average of 40.2 watts per hour times maybe 7 hours minimum for decent sleep for me, so about 281 watts total.

    I am almost completely ignorant about electricity -- I get lost in terminology fast. I'm also not very handy. And I'm low income. That by itself is a challenging combination because the easiest solution would be to install solar on my rooftop and include a Tesla battery and voila! I would be off the grid for my electricity. But I've looked into that solution and it's too expensive for me. Specifically what makes it unaffordable is the battery.

    I might be able scrape together enough money to buy a "power station" lithium battery, like the Goal Zero Yeti 400 or something similar. Or I might be able to find someone who can build me an acid, deep cycle battery solution, although this has proved hard to find. But then for me it still comes down to the question of how to recharge the battery.This is where I get completely stuck.

    Solutions for recharging that I'm aware of:

    * Plug into AC in the wall. . Great when you can get it but if the power outage lasts more than a day, wall AC is not available.

    * Use portable solar panels. This seems less than reliable. I've read different opinions about how efficiently the various batteries get charged by solar panels. I don't really know how to figure that out. Even when they are charged efficiently, it requires a sunny day. What if the day isn't sunny?

    * Plug into car while it's running. The specs for the last lithium battery I checked out say that it takes about 6 or 6.5 hours to charge it using the car. All this time the car must be running. Who can afford to idle a car for 6 hours, especially in a disaster scenario when gas stations may or may not be available to refuel? But even if gas is available the solution seems completely impractical.

    * Fuel generator. This seems like the most efficient backup to solar, but honestly generators scare me and I can't figure out the logistics of how to run them safely -- not that I actually know what I'm doing here. They say the generator must be run outside and at least 20' away from structures. I have a small back yard which is also on a slope. Hard to figure out where to put a generator safely. Also, it's fairly visible and easily accessed from the street. Front yard is just a tiny postage stamp lawn open to the street completely. Also on a slope by the way. Best I can tell, I would have to sit on the street with my generator waiting for it to charge my battery.

    Then there's the scarier question of where to store fuel. I'm not supposed to store it inside, so I don't know where I'd put a tank or how I would keep it safe. I already keep tiny propane canisters for my camp stove in my basement, despite the instructions not to, because there's nowhere else safe to put them. But, like a big supply of gas or propane? Where would I put it?

    So, given all that, I just really don't know how to proceed. Would someone who is a more experienced off-the-gridder be able to advise me please?

    [*] Aside from natural disasters I should also say that I live in Northern California, where our power supplier has been turning off electricity to large parts of the state for days at a time when there is a danger of wildfires. It hasn't been fun.
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  2. DKR

    DKR Raconteur of the first stripe

    A full profile page is needed to be of any help.

    What city for example, to understand solar potential. IOW tell us more...
    sec_monkey likes this.
  3. jpek

    jpek Monkey

    I don't see where in the profile I'm supposed to provide information. City is Oakland. What else would you like to know?
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  4. TnAndy

    TnAndy Senior Member Founding Member

    Rather than attack this from a 'how to keep the CPAP running' point of view, (which isn't all that hard BTW) I'd personally look into WHY you're connected to a respirator to allow you to sleep.

    So to the 'what else would you like to know' question: What is your height and weight ?

    You don't have to's none of my business of course, but you came seeking help, and I'm honestly trying to help from another angle. You may well have some respiratory issue, but my guess is the vast majority in growth of use of these devices IS due to our lifestyle more than real need. Seems to me the medical industry (and it IS one) is more about selling us STUFF like pills and machines to further their business model rather than to get us into being healthy, and destroying their customer base :D

    I ask this because I'm of the age where the pounds added up on me......they sneek up on you over the years, and as of the end of January, I was 255lbs at 6'0". I'd had a near constant cough over the last few years and according to my wife, slept breathing, she says, would almost stop for periods at night, then I'd gasp in air like I'd just surfaced water, snort, wheeze and so on much of the night. All the classic symptoms for going on a CPAP according to her and my doctor...who wanted me to go get one of those sleep studies done. Plus my fasting blood sugar, checked semi-annually, was running over 100, in the 'pre-diabetic' range for several years....pointing out to me where I was headed with that issue.

    Being fairly resistant to doctor's advice.....I find most of them merely want to treat symptoms rather than problems, I never went for one. But I have a good friend that uses one, is over weight, drinks way too much beer (he freely admits it) and I know of a couple others in a similar situation.

    Starting in January, I finally decided to do something about my weight....not from a respiratory point, but just overall health. I'm 70.....I'd like to get 20-30 more years IN decent health, and I could see my weight was clearly going to be an issue going forward.

    So I started fasting, beginning with a 5 day nothing-but-water fast, then 'intermittent' fasting where you only eat a good meal, but only once every 24hrs, giving your body time to lower your blood sugar and force it to burn your fat reserves. There are many videos out there, I found Dr Jason Fung, a kidney specialist on YouTube to be an excellent source of HOW to fix Type 2 diabetes if you have it, why you have it, how to prevent getting it, and so on......but weight loss and future control of weight is the key. THAT is why I went on this kick.

    BUT a huge side effect of my loss (I'm down 40lbs now to 215, going for 190 or less eventually, and keep it there) is I now sleep like a baby. Wife says I'm so quiet, she has to really listen to see if I'm even breathing. That on/off cough I've had literally for years, seems to be gone (knock on wood).....which may have been due to weight, or now NOT eating commercial bread products at all, or cutting out my intake of Splenda sweetened ice tea (I used to drink several glasses/day year round) water, or water with lemons, is my choice of drink.

    Long post, I know, that did nothing to address your original question.....which I can still answer if you really need it.....but were I you, I'd look seriously at WHY you're dependent to a device like that to start with. None of the above is medical advice, but some of it does contain some common sense......which seems to be lacking for the most part in the medical industry.
    Last edited: Jun 16, 2020
  5. jpek

    jpek Monkey

    TnAndy, the question of why people have sleep apnea and if there are better ways to treat it or prevent it is an involved one and I don't want to have it here at this time. Suffice it to say that for the foreseeable future I've been convinced that I need to use a CPAP and that this is important for my long-term health and good functioning. I don't mind discussing how I come to that conclusion, but I don't want to do it here. Here is where I would like to get help on how to power my CPAP machine when the grid goes down.
  6. TnAndy

    TnAndy Senior Member Founding Member

    Sure, fine....we'll not have that discussion if you choose.

    You have to plan on how long the grid will be down in order to make a plan for it. IF the grid is just down for a short period, hours or even a couple days, you can get by with a battery bank that does recharge/keep charged, by the grid.

    IF you're planning on more than a couple days, solar is the way to go IMHO.

    So what are your parameters.....HOW LONG.

    Also, how did you measure the 40.2 watt draw per hour ?
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  7. jpek

    jpek Monkey

    How long: I'm thinking several scenarios:

    • A 1-day occasional power outage. In a way I'm not too worried about this because even if I don't sleep with my CPAP for one night I'll survive.

    • A 2-3-day electrical outage. Our power company has been doing this to us in the fire season. My house hasn't been affected yet, but it could be. During these outages, some electricity is available in the city, but some neighborhoods are down. The same 2-3 day scenario would probably also apply to camping trips, though those are definitely a second priority for me.

    • A 2 week outage. May include other things such as gas. This is the basic prepping scenario of being ready to shelter in place for two weeks with no government services or aid. Example: there is a major earthquake or other disaster and first responders are swamped or otherwise unavailable. What do we need to do to stay safe, fed, relatively healthy, etc.?
    How I measured my electrical usage was by using this gadget: I measured it over a seven-day period and then averaged.
  8. arleigh

    arleigh Goophy monkey

    My life is built around a battery system.
    I use several means to charge this battery bank.
    grid, solar, wind, alternator, generator.
    for something you are going to run extensively it needs to tolerate being drown very low. car batteries cannot take that, but deep cycle batteries can.
    I run primarily on trojan 6 volt golf cart batteries for the shop and house .
    I am holding off till I can get the latest technology, however that may take a while.
    I know that battery powered units are available , i have a friend going that direction.
    Gator 45/70 likes this.
  9. ghrit

    ghrit Bad company Administrator Founding Member

    OK, seems like you have the first step figured out, know the load. I have to say, that load is WAY small, and, if accurate, should be easy to satisfy. That alone is (obviously) not enough to design a system, and knowing how long you intend to run it without commercial power available is critical to system sizing and selections. Next step, make a decision on time off commercial power to design for.

    Once you have that dialed in, you figure out the (kilo)watt hours you'll need to sustain operation for the selected off commercial power duration. That will size your battery. (We'll talk batteries later, not ready for that yet.)

    For the time being, keeping the battery charged will be the duty of the grid. Bear in mind that your machine wants what? 120VAC? That means an inverter is wanted. Even if you get a small portable genset for grid down, you need the conversion gear. There are inefficiencies involved, so don't be surprised at how the numbers can grow.

    I am not trying to over-complicate this for you. Nor is it important how you came to need the machine, that is for you to deal with. Most of us are very conscious of cash and land shortages, so we have a pretty good picture of your situation. From what you said, I get that you're a renter, therefore apt to be unable to add stuff to the house. We'll keep that in mind as well, you'll need to go full portable.
    Gator 45/70 and sec_monkey like this.
  10. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    As a long time CPAP user, and an Off-Grid liver, way out in the Alaskan Bush, I can tell you what I use, and how well my system works... Which is “Very Well”... First thing is that I use a Resperonics REMstar Pro C-flex+ machine... Second, I modified the AC Power Supply which outputs 12Vdc, with a Automobile Cig-Lighter Plug, so that my CPAP can run off 120Vac or 12Vdc which ever is available at my sleeping location for the night... Third, My Cabins are setup with 120Vac and 12Vdc Power Systems in each Room.... The 120 Vac comes from a Trace 5.5Kw 48Vdc Inverter/Charger w/ 800 AmpHours of Batteries.. This is charged by either a 12.3Kw 1800 Rpm 3Cyl Lister Water Cooled Diesel Genset, or my Fairbanks/Morse 45B 3Kw 1200 Rpm Single Cyl Diesel Genset.. Each of my cabins has a 12Vdc System that consists of set of 4 ea. T105 6Vdc Batteries wired in a Series/Parallel setup that gives me 400AmpHours of 12Vdc Power... These Battery Banks are charged with 400Watts of Solar Panels run thru an MPPT Charge Controller and a 120Vac/13.6Vdc 35Amp Linear Power Supply that charges the Banks whenever the Gensets are running. In the Alaskan summers, the Solar is enough to keep the 12Vdc System Batteries at Full Float, but during the winters we have to run the Gensets once every couple of days to keep everything around the place running..

    So, my suggestion to you would be get yourself a couple of T105s wired in series for a simple 12Vdc System, and a good 120 Vac/12Vdc 12Amp, (Minimum) Battery Charger, that feeds your CPAP Machine Input, and if you are really worried about a week or more of No-Grid Power, a Couple of 200 Watt Solar Panels and a Good MTTP Charge Controller... You will be fine, baring the Sun doesn’t rise once every 24 Hours, anymore..
    Ganado, Gator 45/70 and sec_monkey like this.
  11. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Load was checked by ? a KILL-A-WATT unit or just a figure .
    Looks like a Job for a
    Solar Morningstar SureSine, 300 Watt Sine Wave Inverter 115VAC
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  12. ghrit

    ghrit Bad company Administrator Founding Member

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  13. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    12Vdc @ 6 Amps = 72Watts. That is the 120Vac/12Vdc Power Supply that came with my machine.. I am sure it doesn’tdraw that much when actually running, but I have never actually looked at the Dc Amps when it is running... Maybe when I get cleared to get out of this chair, (hpoefully on Thursday) that is something I can look at...
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  14. ghrit

    ghrit Bad company Administrator Founding Member

    Got it, thanx. So the 40ish may be real. Still, for design purposes, the nameplate rating on @jpek 's machine would be nice to have.
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  15. UncleMorgan

    UncleMorgan I eat vegetables. My friends are not vegetables.

    I think I can help with this question.

    The first thing to do is seek a simple solution.

    First, what voltage does your CPAP machine actually use?

    Of course, it plugs into the wall, but so does a computer--and it has a Power Supply that converts 110V AC into (usually) 3.3 volts, 5 volts, or 12volts DC.

    110AC is a lightning bolt compared to the energy that most small devices use.

    Like hair dryers, for example. The heating coils use 110AC, just like a toaster. The little fan inside uses 12V DC.

    That's convenient!

    So let's work backwards:

    1. Nose to CPAP mask.
    2. CPAP Mask to Hose
    3. Hose to Hair Dryer. (See Note!)
    4. Hair Dryer to 12 volt car battery. (Or riding mower battery at half the cost plus better portability.)

    Almost done!

    Note: Test first! Set the hair dryer on "Cold" and plug it in. Run the output air into the CPAP hose, and put on the mask. If the air pressure (speed) is good at Lo, Med, of High, you;re golden, and it's time to get rid of the old wall-socket power cord and convert the hair dryer to battery power.

    Here's how you convert the hair dryer:

    1) Unplug it.
    2) Unscrew the screws that hold the halves of the hair dryer together.
    3) Remove everything except the on/off/Lo/Med/High switch (or switches) and the fan they are connected to. Get rid of the AC power cord, the heat switch, and the heating coils entirely. You'll see which wires to cut.
    4) Make a new power cord: Get a nice long lamp cord and cut the plug off of it. Strip all four ends of the cord back about 3/4". Connect the wires at one end to ordinary car-type battery terminals.
    5) Install the new power cord: Strip the ends of the wires coming out of the switch about 3/4" back. Twist the ends of the wires from the switch and the ends of the wires from the power cord firmly together. (Individually!) Insulate each connection with electrical tape.
    6) Put the halves of the hair dryer back together, running the new power cord out where the old power cord was. Almost done.

    Connect the battery terminals to the battery. Turn the switch on the hair dryer to "On". The fan should run at low, med., or high, depending on where the speed switch is set.

    If the fan blows air out. you're good to go. Mark the "+" side terminal with red paint or nail polish.

    If the fan sucks air, swap the terminals and then mark the "+" one.

    That should fix the problem.

    Ever after--the battery will be good for years--just hook it up and select the pressure you need by Lo, Med., or High.

    Recharge the battery with a cigarette lighter adapter fitted with MARKED battery terminals. You can set them to just push on and pull off by hand, with no tools required. Ditto for the terminals on your new power cord.

    If, after wiring up the new power cord the fan won't run, you've either hooked up the wrong wires or had a soldered connection pull loose--probably a switch wire. Check everything out. Experiment with the wires. At 12V, you can't get hurt, and you can't set anything on fire. And you can make it work.

    At the very worst, you might have to buy another hair dryer at a thrift store (@$3.00) and rewire it with the knowledge you gained messing up the first one.

    If you hate hair dryers, you can also use a computer fan and an inline switch for the power cord. Computer fans are designed to run for years.

    Converting a hair dryer, though, is VERY simple and easy.

    Don't forget to put a filter in the end of the hair dryer.

    One last thing:

    If you want to get fancy, put a complete 12v adapter & socket in the power cord. Then you can unplug the new power cord, and plug the male adapter into a cigarette lighter in your car to charge the battery. You'll never have to worry about hooking anything up backwards.

    Get something like this:

    Auto car motorcycle truck cigarette lighter power Socket plug adapter 12V 24V | eBay


    Auto car motorcycle truck cigarette lighter power Socket plug adapter 12V 24V | eBay

    The ones with color-coded wires are easiest to install. You can skip the battery terminals entirely and attach the wires from the male plug to the battery with small hose clamps. New battery terminals can cost $7.50, so it's actually cheaper to go with the connector, as well as more convenient.
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  16. 3M-TA3

    3M-TA3 Cold Wet Monkey Site Supporter++

    @jpek I'm a CPAP user and hopefully another 75 lbs of weight loss will result in being a former one. My solution for camping with a CPAP might be useful to you:

    Get a second car battery the same size as your vehicle.
    Get a plastic automotive battery box
    Get a car accessory socket and a set of battery terminals. Some wire if needed.
    Assemble. Note that there is enough space between the battery box lid and the box for your wires to pass through

    Now use your 12 VDC CPAP cable and you have power for at least a couple of nights. When it runs low, charge it from your car for a while. Now, swap the batteries and let your normal driving charge the one your CPAP depleted. Usually when I'm camping the exploratory drives will fully charge battery A while battery B is in use by the CPAP.
  17. coloradohermit

    coloradohermit Monkey+++ Founding Member

    jpek, I hate to ask a stupid question, but have you consulted with your oxygen supplier company about what alternatives are available for power outages? DH was on oxygen 24/7 for years, but not cpap. As backup in case of power outages we had an H tank of oxygen. I don't know if a cpap could be hooked to one of these tanks or if the tank with a regulator and canula would provide enough nighttime oxygen to get you by.

    "What is an oxygen H tank?
    The steel "H" medical oxygen cylinder is a great choice for oxygen back up units or to use to supply a oxygen filling system. The steel "H" cylinder can supply up to 7079 liters of oxygen."
    Gator 45/70 likes this.
  18. DKR

    DKR Raconteur of the first stripe

    Thanks - that allows the solar isolation to be calculated.

    Make & model of machine? I'll look up the tech spacs on line with that...
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  19. Merkun

    Merkun furious dreamer

    +1 Back to basics.
    Gator 45/70 likes this.
  20. Big Ron

    Big Ron Monkey++

    Look at how much power the CPAP uses and figure out what it would take for 8 hrs worth of power. I bet a really big battery is need with a pure sine wave inverter. Time for you to read up on batteries and off-grid living. Using LIFEPO4 batteries would be my suggestion.
    Gator 45/70 and Cruisin Sloth like this.
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