UPS and Resmed

bbeck4x4 wrote:you may be right, but when I turn the m-series humidifier over it reads 12v 4.16a

That's ~50W of energy just for the humidifier, so its still an expensive proposition (in terms of battery weight and capacity) to run it off battery power.

Possibly not an issue if you have a fixed location "power outage protection" battery setup, or a convenyance that has a hefty secondary battery supply built-in, but otherwise running the flow generator plus the humidifier is going to be a big ask in terms of easily achievable 12V battery power supplies!

Cheers,

Bill

To confuse the issue even more, I contacted Fisher & Paykel and was told that a stepped sine wave would be no problem for the F&P 150 humidifier. Maybe they just want to sell more of them LOL - but they actually recommended getting an inexpensive inverter, virtually all of which generate stepped sine waves.

AC voltage "cycles," up and down; that's why it's called alternating current. When you see the "60 cycle" or "60Hz" specification on most U.S. AC-powered devices, that means the device requires alternating current that cycles up and down 60 times per second. All this sine wave stuff simply refers to the manner in which the voltage cycles - smoothly, or in a stepped (almost digital) fashion.


Here's a graphic showing a modified (stepped) sine wave superimposed over a true sine wave.



BTW, I went through all this UPS stuff not long ago and pretty well decided to just go with some sort of battery solution along with an inverter for the humidifier. The deal breaker was in realizing that UPS' are designed to keep your stuff running for maybe 15 minutes - any longer than that, and the prices of them skyrocket. And - most of the ones costing less than $300 generate stepped sine waves.