(01-11-2015, 02:23 PM)Rivky Wrote: I am listening for any good ideas and may call my BiPAP company tomorrow.
No if's, and's, or but's, if you're doing this in a fixed location, such as your home, the easiest solution is a lead acid battery or two. Think something the size of a car battery. A car battery will actually work, but a "deep cycle" battery will last through more power outage cycles. Do your regular maintenance, and replace the battery every 5 years or so.
One battery the size of a car battery should give you several nights worth of CPAP.
Fancier batteries, such as AGM or gel cells, have the advantage of not being spillable. Lithium batteries are lighter but much more expensive. If you're not moving them around, it doesn't matter that much.
You'll need the appropriate DC cable/power converter for your VPAP III. I believe it won't run the heated humidifier on DC.
You can also use an AC inverter, but it will waste some power and cost you some run time. I believe for the VPAP III, you'll have to have a pure sine wave inverter, which is more expensive and usually even less energy efficient. You can probably use a normal "modified sine wave" inverter with the VPAP III as long as you remove the humidifier. MSW inverters will damage the heated humidifier for S8 series machines.
Many of them now have "stepped approximation to sine wave," which is sort of somewhere between MSW and pure sine wave. Unfortunately, there's not a good way to tell how well the particular inverter approximates a sine wave, or how your equipment will react.