Asking because I know we have some electrical engineer types on here.
We have a CPAP machine that we’d prefer stay running when our power company does ridiculous things. With the number of short, random, completely-unexplained outages, I swear our local grid is held together with baling wire and duct tape sometimes.
I’d very much like to plug this into a garden-variety UPS. This is both for flexibility with other devices, and long-term cost savings with the ability to swap out batteries. This is a low-draw device, between 20 and 80 watts or so depending on how it’s operating.
The (expensive, proprietary, non-user-serviceable) CPAP batteries I’ve seen make a huge deal out of the fact that they provide “medical equipment grade” pure sine wave power. But keep in mind that this thing normally plugs into my household wall outlet, which I very much guarantee isn’t “medical equipment grade” anything.
If I buy a regular “pure sine wave” UPS from a standard vendor (APC, CyberPower, etc.), is there any reason y’all can think of that I can’t plug my CPAP into it?
This UPS has a clean sine wave output so should work fine with a CPAC machine. The other part of the equation is run time. Do your outages last all night. Does you machine have humidifier and hose heater which effect power useage. Find the specifications for your machine then look up runtimes for those power requirements vs UPS VA rating.
“APC UPS Back-UPS Pro 1000VA Sinewave UPS” It is available on Amazon and there is a 1350VA model available for more $’s.
That’s the most irritating part. Most of these outages are just long enough for anything digital to lose power and reset. I don’t actually need all night runtime, but a couple of hours backup would be very, very useful!
If you have any issues at all with that you will not be able to get a new machine or use any sort of warranty or repair services. More troubling, your medical insurance may fail to cover you if you experience health issues due to loss of the cpap machine or changes in how it operates by being plugged into an “unapproved device”.
Neither of those is a valid electrical reason not to do it but something to consider anyway.
Not too sure about this particular model but most power stations do not provide all the ‘protections’ that most UPS’es provide such as voltage regulation, really quick switch times (if line-interactive), etc. It’s not just about keeping the device running once power is out.
I second the comment from @OogieM. It is the lesson that my roommate in grad school drilled into me about downside risks. There are those risks that common and not dangerous, and there are those that are uncommon but life-threatening. Do not ignore the latter by searching only for things to cover the former.
Before you purchase anything, get/rent a plug-in waveform analyzer and track the quality of the wall socket output over a reasonable period. Also contact the vendor for the UPS to ask for a report on the nominal and emergency waveform outputs from their unit. Finally, contact the CPAP vendor with the two pieces of information at hand. Ask them to certify that attaching the CPAP to the UPS will not void its warranty or decertify its life-saving function at any point, without or with power outages under consideration.
If you get lucky, you may even connect with a technician at the CPAP vendor who is kind enough to tell you straight up a recommended UPS instead of their battery.
Speaking as a retired electrical engineer, a CPAP machine is really nothing special. It has electronics and mechanical components (pump and pressure regulation). And a bog-standard power supply in-line with the power cord so that the unit itself has no dangerous voltages present. Because it is designed to work in a home environment, which tend to be electrically “sloppy”, a good UPS would be fine.
But “garden-variety” UPS can be an issue. You definitely want one that has a sine wave output (usually synthesized to a close approximation) and not all meet that requirement. Unless things have changed since my last purchase, low end APC models were not sine wave, and CyberPower was making a point there theirs were.
Yeah, this is something I’m definitely going to keep in mind no matter what I do.
Oddly enough, it looks like there are rumors that some of these units might be considering USB-C PD as a future power supply option. Obviously that won’t back-port to mine, but it’s interesting that even these companies seem to be getting with the times.
My CPAP machine runs on 24v DC supplied by a power brick. The AC to DC conversion should smooth out any power issues from the UPS. I’ve run the machine off a modified sine wave inverter in my RV with no issues. Any pure sine wave UPS should work fine. Only problem will be the UPS alarm waking you up.