supplying power all night

Discussion in 'Camping & Outdoor Gear' started by aedgington, Nov 7, 2005.

  1. aedgington

    aedgington

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    i'm looking for ideas about how to power my cpap all night. for those unfamiliar with this lovely device, it keeps those of us w/ sleep apnea from snoring or suffocating.

    i had tried daisy-chaining computer ups battery backups, but it looks like apc won't let you do that. i also found out it was limited to 99 min, regardless of power draw.

    this little sucker draws like 8w, not much, but i need to power it all through the night. i don't know anything about car batteries, but i'm assuming i would just wake up w/ a dead car battery?
     
  2. petescoffee

    petescoffee

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    How about a power invertor on your car battery and use a deep cycle battery. There is also a Odysey battery in one of the new 4x4 rags that is supposed to be military grade and have tons of back up juice in it. If you put a dual battery set up in your car you would probably have juice to turn over your car in the morning.
     
  3. photogod

    photogod

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    I have a friend that has a dedicated battery in his boat that he runs an inverter off of and runs a small fridge all night and half the next day. I'm not talking a 12 volt either, it's a small colledge kids fridge. You could add a battery in the rear wheel well and put the outlet in the plastic pannel then run the inverter and cord where ever you need to. Charge the battery the nevt day. If your apnea isnt serious you could look into an adjustable mouth brace to help keep your jaw from colapsing. I use one of these devises and it uses no power and fits into your pocket. Find a dentisr that specializes in TMJ and they should be able to point you in the propoer direction. Good luck
     
  4. aedgington

    aedgington

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    hmmm. dual battery sounds like a good way to go. i might test it out before i order the tray & do the wiring. i'm sure a fridge draws more power...

    unfortunately my apnea is pretty bad. i did the upp surgery w/ no results. sad thing is, i'm not overweight, so there's nothing i can really do.
     
  5. Tools R Us

    Tools R Us

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    A booster pack, jump box may work well for this? Some have inverters built in.
     
  6. alia176

    alia176

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    I wonder if you can find out if your device can run off of DC power. If so, then have an electrical whiz design a transformer circuit that can run on 12vdc. Inverting DC to AC is inefficient with the inexpensive inverters and adds to your total power consumption. However, if it's strictly an AC device then perhaps have the same whiz design or purchase a more efficient DC to AC inverter circuit so that your total consumption remains low. As you said, dual battery should be a big bonus in this scenario; afterall, this is a more serious matter than running a fridge!

    Good luck.
     
  7. NorCalDoug

    NorCalDoug problems solved daily...

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    Complicated solutions to a simple problem :D

    Get one of those portable battery packs that you can use to jump start your vehicle.

    I found one at Brookstone.com a couple years ago. When you're shopping for one, make sure it holds enough power for a 10 to 20 hours of use. You'll need to know aprox how much power the cpap draws per min/hour/etc. and divide that by the battery life given that amount of draw.

    I did a quick check, but didn't see the model of portable battery that I have, but mine has plug in cables to use for jumping -- I've used this several times in the past -- it works well enough.
    Mine also has an integrated inverter, so I can plug in 110v plugs as well as use the 12V outlet that's built in. Mine charges via the car battery - through the 12v plug and also from standard household 110v via another plug.

    do a google on xpower portable batteries -- you'll find quite a few options. you might find something similar at costco.com or your local costco. If you have a mall close by with a BrookStone store in it, they might have some in stock as well -- just navigate through the trinkets and gadgets they have in there ;)

    Good luck with your search and feel free to PM me if you have any specific questions about the battery pack that I have.
     
  8. alia176

    alia176

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    After 10 hours of usage, how will he recharge the battery pack if he's still camping?
     
  9. NorCalDoug

    NorCalDoug problems solved daily...

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    2 battery packs? :D

    I'd suggest plugging into the vehicle via 12V outlet and recharging that way. Mine allows for this, in fact, I recharged mine at Surf-n-Turf this way.
    The 12v deep-cycle on the tent trailer died because I wasn't smart enough to turn off a fan during the day. The heater for the trailer requires 12v power to blow -- no 12v, no heat (even though it's powered via propane).

    So, since my trailer connector also powers the 12V battery, I plugged in the trailer connector, started the 80 to recharge the trailer battery and to supply power to the trailer itself. I also plugged in the battery pack to the spare 12v outlet in the cargo area.

    Kind of an expensive and inefficient generator, but it worked.

    ANOTHER possible solution is to get something like the Honda EU1000i generators. It's super quiet, you can put the generator 10 to 20 feet away, get a long extension cord and connect your cpap to that.

    Assuming you're hauling the cpap...which isn't very compact...you're going to have a vehicle close by.

    The honda generator is not cheap...but it's VERY nice.
     
  10. Tools R Us

    Tools R Us

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    At 8W draw it would take weeks to kill a jumper pack, an inverter plugged into the lighter would work fine with that small of a draw.
     
  11. rusty_tlc

    rusty_tlc Dain Bramaged Member

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    Whatever else is said here I have this generator and it kicks. We can dry camp for weeks in the dead of winter and just charge the batteries for a couple of hours a day to run the forced air heater. You can have a normal conversation while standing right next to it. They are pricey, but I've had mine for a few years and feel it has more than paid for itself.

    Edit: Seems like a good investment if you depend on a medical device, power can fail at home too.
     
  12. NorCalDoug

    NorCalDoug problems solved daily...

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    The portable battery that I'm referencing is something like this: Xpower portable battery

    The one I have is from the same company, but looks much different -- I bought mine a couple years ago...the style has changed quite a bit since then.
     
  13. desertdude

    desertdude SILVER Star

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    :D :D :D :D

    Well worth the $$ to save you life ;)
     
  14. aedgington

    aedgington

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    i'll have to try this, i have an xpower jumper/inflater already. i had just figured if the apc ups' didn't have enough juice, that wouldn't either.
     
  15. MrMoMo

    MrMoMo That's not rust, it's Canadian patina...

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    Ok you folks are WAAAY overthinking this. You said that it draws 8W. If that is correct and I am assuming that it operates on 110 AC, go to your nearest Auto supply store and buy the cheapest Cigarette lighter inverter you can find. I can get them here locally for $30Canadian - Circuit City has them. The Smallest cigarette lighter inverter I have seen is good for 50 to 75W.

    So. If you have 8W @120V AC you are using 0.06667 Amps AC. If you pull that out of an inverter you would need 8W @ 12V DC = 0.6667 Amps DC. Remember how much that $30 Inverter can supply.

    OK, so now you want to run it all night. You now need battery Reserve Capacity. First of all, do you think you could run your stereo all night? Probably - be able to start the engine in the morning - probably. So how many watts is your stereo? Check the back - likely has a 10A fuse in the back of it, so MAX it can be drawing is 120W.

    Now for the funky part....

    Lets say you have a 24series battery.. you then have about 75Ah reserve
    If you have a 27series battery you have about 100Ah reserve

    Lets say that the inverter is extremely inefficient, and then you run back down to DC through a wall plug converter -so you as much power to get your power - upping your total load to a whopping 16watts.

    WITH A 24 SERIES YOU GET OVER 23 HOURS before your battery is depleted to 1/2 - which is where you should stop using it.

    Remember - this is with a CRAP inverter at CRAP efficiency on a small 24 series battery.

    With a 27 series battery, a decent inverter (most are 80% efficient) load of 10W or so, you get 50 hours of use.

    Your stereo, balls to the wall, fully loaded up with its amp at full power, driving a tape or CD would be able to run for over 4 hrs - but it really doesn't draw 10 amps so it would run much longer than that.

    I have a HUNCH that will get you through the night.

    BTW - I do this sort of crap all day - I design electrical systems for Fire Rescue boats, I have to run MUCH larger loads off of batteries. The current project I am working on will have close to 300A @12V (3600 Watts) of house load, with twin 235A 12V alternators to charge it.

    Hope this helps you out, and you are not afraid to kill your battery!!, worst case, if you are really paranoid, install a totally seperate battery. The easy way to maintain a charge on it would be to run a wire through a relay from your main battery to your secondary battery, with the relay trigger hooked up to your alternator, this way, whenever your engine is running it will charge both batteries, but as soon as your alternator is not putting out power, it will disconnect the second battery from the system.

    If you have any questions feel free to e-mail me - I can draw you up a simple schematic.

    Bruce
     
  16. NorCalDoug

    NorCalDoug problems solved daily...

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    You think we're overthinking stuff?

    Geez dude. I haven't heard that much gobbledegook since my high school physics teacher started rambling on about his home made PC clone that he built back in 1982 :rolleyes:

    Battery pack or small generator. Done.

    And...you're not tied to your vehicle if you have something portable.
     
    Last edited: Nov 15, 2005
  17. Arya Ebrahimi

    Arya Ebrahimi

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    What about just getting one of those auto-disconnect things that cuts off anything drawing the battery down once the battery's charge level reaches a certain point? The idea is it's supposed to leave you with enough charge to start the vehicle. I'm pretty sure they're cheap, and I think it would be the most cost effective option since you already have an inverter.

    Ary
     
  18. TheGr8Doughboy

    TheGr8Doughboy

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    But if it cuts the drain off the battery, won't that defeat the purpose? The primary goal is to keep the apc going. Secondary goal is to have some juice lefft over to start the battery. No sense in accompolishing the second goal at the cost of the first one.

    Chris
     
  19. NorCalDoug

    NorCalDoug problems solved daily...

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    But what use is a dead battery? I think Ary's talking about a vehicle's battery, not a portable or 2nd battery.
     
  20. BMAN

    BMAN

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    Which CPAP are you using exactly? Is it a Respironics Remstar(probably) or a GoodKnight 418? Does it help? and How long have you been on it? I've been thinking about getting in for a sleep study but haven't yet, I'me sure it would help though.
     
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