These retail for $300+ and have GREAT reviews!
PO-160UPSv2 159W 110-240V UPS CPAP Battery & Backup Power Supply Compatible with Philips Respironics DreamStation 1 & 2, ResMed AirSense 10 & 11, or Luna 2 & G3
Introducing the Portable Outlet Uninterruptible Power Supply PO160UPSv2 by Sunset. This power supply is perfect for those who need a reliable and uninterrupted power source. It is designed to meet California Prop 65 Warning standards and ensure that you are protected from cancer and reproductive harm.With its compact and portable design, this power supply can be easily taken on the go and used anywhere. It is compatible with a wide range of devices and has a maximum output power of 160VA. The PO160UPSv2 is a great choice for anyone who needs a reliable power supply, and it comes with a peace of mind knowing that you are protected from cancer and reproductive harm.