Topic: Is there a way to power normal 120Volt products off my 12V SLAs? If so how?

[Bdifr78]

Ok so this is a strange question but I gotta figure some solution out. 

I have recently been diagnosed with sleep apnea.  So I just got a CPAP machine for use while sleeping.

To fill those of you in that are not farmiliar with sleep apnea, it is a disorder where the opening to your trachea closes periodically through out the night.  So your sleep is constantly interrupted by your body having to open this passage back up and gasp for breath.  You don't actually wake up but, technically your body and brain leave the sleep mode.  In fact you almost never enter REM sleep.  So let's say you sleep 6 hours a night, your body only receives about an equivilent to 2-3 hours of rejuvination from normal sleep.  This actually effects a lot of your normal body functions.  It raises blood pressure, it slows your metabolism to almost a stop, and in general your brain doesn't function as it should.  Additionally every once in a while someones body doesn't re-open your breathing passage quick enough and you die.  Ala Reggie White.  This is very rare though.  So this disorder is corrected by using a CPAP maching.  The CPAP is basically a machine that pumps air through your nose down to your treachea and keeps the passage open all night. 

So I just got my CPAP machine and am so siked about actually getting real sleep for the first time in years.  But here is my dillema.  I am a true festivarian!  I will be attending several festivals this summer, as I normally do.  So what I am wondering is if there is anyway to run my CPAP maching off on an extra 12V SLA battery.  I imagine there has got to be a way to convert the plug, but what about the voltage.  The unit does have a jack for 12V power and you can order a car adapter incase your power was to go out and you needed to sleep with the CPAP.  But it takes 6 weeks to order, and I will have already attended 2 festivals by then, Haymaker next weekend, and Bonnaroo.  Plus I have a wonderful air mattress that I use in my tent and would like to avoid sleeping in my car if possible.  I desperately want to be able to use the CPAP at festivals.  We all know that the festivals are hard on your body and mind and we all know that you get maybe 4 hours of sleep a night if you are responsible and don't party too much.  So imagine if through out Bonnaroo you got an equivilent to only 1 or 2 hours of sleep each night.  You are not gonna be doing as much dancing as you would like to by the time Saturday afternoon rolls around, and you would feel like hell on Sunday, and Monday driving home would also be hell.  Add into the equation that I am a very large man and struggle physically at festivals anyway(the heat, the walking, the standing, the dancing, the lack of nutrition) its a tough task for any 300 pounder like myself.  But live music is my passion, and even with all of the things I just mentioned I would not trade the festival experience for almost anything.

I know there is a way to run my CPAP off of a 12V SLA, I just don't know how.  Since it has a jack for 12V power can I just go to radio shack and buy some adapta plugs to make this work, or is there more involved in this equation.  Please someone help me out.

Thank You,
Joe

[Lil Kim Jong-Il]

You can determine the power requirements from a label near the power connector on the machine or off the wallwart if it uses one.

If the machine wants 12VDC, you can run it off an SLA.  If it draws 1A, you'll need at least 10A hour capacity for each 8h night night.  You might find it more convenient to get a large capacity battery and go a little less on the reserve.  It's just a matter of wiring a power cable the same as if you were wiring it for a preamp.

If the machine wants 12VAC, you run the wallwart off a power converter connected to your 12V battery.  In that case you will loose efficiency due to the conversion.  I'm not sure what that is but it may be as much as 30% (seems too high to me but I'm being conservative).  So for a 1A draw to your machine, use a 13Ah battery for each night.

When you figure out how much power you need, just scale the battery size as needed.  You can get batteries and a powersonic charger at most electronic supply houses.  If you can't find a proper plug, you can hack the wall wart cable with 4pin XLRs and then you can swap between the batteries and the wall wart as needed.  Also, you'll have all those extra 12V supplies already wired for your rig.

Edit: I just noticed that you are in DC.  You can get everything you need at Arcade electronics in Alexandria.  Also, if you need help let me know.

[MattD]

If you need a big 12V battery, I have a 12V 12Ah that I've been trying to sell for a few months.

[Bdifr78]

+T for both of you!  As you can tell this is a subject that is very important to me.  Thank you so much for the response.  I am gonna go look at the power requirements and see if I can figure this out.  If I figure out whats going on I might want that 12V 12A you got MattD.  Although this company I got my SLAs for my rig off of ebay, Gruber power supply, sells new SLAs dirt cheap.  Lil' Kim Jong-Il, I do believe I might need more help with this thank you so much for the offer.  Can I PM you when need be?

Joe

[Lil Kim Jong-Il]

My mailbox is always open

[krebsy]

Getting that machine will probably be one of the best things you've done for yourself in awhile. My father has pretty severe apnea also. He could always fall asleep at the drop of a hat at almost any time of the day. Since he got that machine, he has felt so much more rested, and doesn't doze off during the day like he used to. To top it off he doesn't snore one bit, whearas he used to snore to beat the band. Sorry I can't help with your powering issue, but a big ole +T towards a future of good sleep, and improved health!!

[Bdifr78]

Getting that machine will probably be one of the best things you've done for yourself in awhile. My father has pretty severe apnea also. He could always fall asleep at the drop of a hat at almost any time of the day. Since he got that machine, he has felt so much more rested, and doesn't doze off during the day like he used to. To top it off he doesn't snore one bit, whearas he used to snore to beat the band. Sorry I can't help with your powering issue, but a big ole +T towards a future of good sleep, and improved health!!

Exactley!  The day I had the second sleep test where I slept with one of these machines, I felt uber awesome after waking up.  I had so much energy and I was so alert and positive and in a great mood.  In fact those feelings actually carried over to the next day too. 

I just got the thing yesterday morning, and what happens last night about an hour after I go to sleep with it...power goes out!  Doesn't come on till about 20 minutes after I wake.  Is that some shit or what?