Hi, I recently acquired a  CPAP Portable OUTLET - Lithium Ion BATTERY to run my CPAP when the electricity is out.

Portable OUTLET (the brand name)

   Model PO 155W
   S# 155W0B1003683
   UPC 8-60001 15050 6
   115W-110V Re4chargeable CPAP Batter
   Power CPAP and two USB devices at the same time
   110-240VAC Switching Power Supply
   3-prong
   AC Discharge Output 60Hz/100W
   USB Output 5V/4.2A

https://www.portableoutlet.com/

NOTE there is no alarm sounded when the battery runs out (and your CPAP stops running)

You will need to turn OFF your CPAP humidifier to prolong the battery life (mine powered my CPAP  for 6.6 hours with the Humidifier ON)

NEW Portable Outlet 155W - Rechargeable, CPAP Battery

The longest lasting, most versatile CPAP Battery
The Portable Outlet is the only battery on the market that can power any brand and model of CPAP or BiPAP without any additional adapters or accessories. That's because our 110 Volt input port is as simple as plugging your CPAP into the wall in your bedroom.

Watch the video below to learn how to use, test and charge the Portable Outlet in North America and overseas...

The most features of any battery
• 155 watt backup battery
• AC output: 110v AC 60hz/100w
• Two USB ports 5 volt 4.2 amps

• Works with all CPAPs/BiPAPs
• Does not require additional adapters to power CPAPs/BiPAPs

• Includes a Wall Charger
• Includes a Micro USB Cable
• LED power indication meter
• Meets FAA/TSA Lithium-ion Battery Standards
• Over 500 charge cycles
• Recharges in less than 4 hours
• Size: 5” wide x 7” long x 1.5” tall
• Weight:  2 lbs.
• 1 Year Warranty

Portable Outlet 155W is only $399.00  USD