RE: battery backup? (Moved to Main Forum)
Welcome to Apnea Board, btaylor!
I'm not sure what the power requirements of your RemStar Auto are, but I'll share with you what I did during the hurricane when we lost power.
I bought two items, an Evercell Heavy-Duty 12V/5A Power cord at Radio Shack (part number 270-048, $12.99), and a Die Hard 750 portable jump starter from Sears (item number 02871486000, $58.99). The DC adapter has a "cigarette lighter" type of plug and terminates in a small barrel which accepts various plugs, depending upon your needs. The purchase price of the adapter includes the plug...I brought my ResMed S8 in with me and matched it up.
Based on the power consumption of the S8...it's a pretty power-frugal little beast...I figured that I'd need at least a 7 to 9 AH 12-volt source to run the whole night (no humidifier, of course) without interruption. I selected a Die Hard unit with a 12 AH battery. They had 15 and 22 AH units as well, but they were out of stock.
Now, this was a bit of a leap of faith. ResMed says that if you run the S8 on 12 volt DC power without their proprietary adapter with the secret toasted-in frosting, you'll turn into a frog or something. For one thing, 12 volts DC is 12 volts DC, and I wasn't about to drop $75.00 on a handful of magic beans. For another, in the aftermath of the hurricane, nobody had the ResMed adapter in stock, just some goofy bag-battery thing (apparently, CPAP manufacturers think that hoseheads can't resist anything in a nylon bag) that sells for hundreds of dollars.
I configured the plug for the ResMed (which means plugging it into the cord with the correct polarity, which is negative-tip as opposed to the more common positive-tip, a little trick which keeps you from using most cheap and readily-available 12 volt cords), plugged it in to the jump starter, and presto...a night of blissful, wonderful sleep.
A couple of caveats, though.
The Radio Shack cable was tagged $12.99 but rang up at $17.99. When I pointed that out, they charged me $12.99, but YMMV. If you have trouble getting the lower price, though, you can always order a Chinese copy on eBay, since you're in the preparing stage and not in immediate need. Probably run you about $5.
The Die Hard 750 worked well, and is on sale right now for $49.99. It has the more desirable AGM battery (I didn't want a "leakable" battery in my living space), a charge indicator, a light, and an integrated dual-stage charger so it can be left plugged in all the time without issue. It weighs 12 pounds which is easily carried by almost anyone. I did a lot of comparison shopping, and I think it's a good value.
You can probably get away with a cheaper unit...I've seen them as low as $29.99 elsewhere. Check Wallyworld, Home Despot, Amazon, Pep Boys, AutoZone, Parts America, etc. Just be sure it has a DC outlet! Some don't, since they're dedicated jump starters. Be careful to check the AH rating, some units have a battery that's only 5 AH or so. That might run your unit all night, but it's not likely to repeat that performance many times, because the more deeply you discharge the battery, the shorter its lifespan. If you don't get a unit with an AGM battery, consider a plastic tray or some other method of containing possible spills. Note, too, that some units come with a cumbersome, "wall wart" charger that can easily be lost. And even units like mine with built-in chargers will need a simple one-outlet extension cord (not included) for charging. And charging is slow.
There are units with huge batteries, dual outlets, USB charger ports, even 110 volt AC outlets (really!) and an air compressor built-in. Tim "The Tool Man" Taylor would love that, but I sure wouldn't want to lug that baby through an airport. Plus in my case, I had to take the thing to work with me every day to charge it, since I didn't want to go two nights and risk killing the battery completely. I wanted something handy and compact and I was pleased with the 750. But it only has four LEDs to show the battery condition. One is pretty much fully discharged and one is fully charged, so that only leaves two to indicate a partial charge. Other units have a digital readout, which I think would be really handy.
If you need to go more than one night on a charge, that should also figure into your purchase decision.
Anyway, it worked for me! It's a cheap, clean, portable and relatively elegant solution (only two components). However, if you blow up your CPAP, you're on your own.
Good luck! Carl
Edited to incorporate archangle's correction of VA to AH
(This post was last modified: 11-13-2012 06:02 PM by ConnCarl.)