I have a bunch of 7-9 hour international flights coming up in the next year. I'm looking for the smallest battery solution that can provide at least 4-5 hours with the humidifier on. Is the $700+ Resmed Power station II really my only option here? That's nearly as expensive as a new CPAP machine. I ...

I also need one for multiple locations, though a bit farther than a different room.

Besides, it's always nice to have a backup without waiting a week for a shipment (I'm international).

I receive a new machine every three years covered fully by my insurance. Is there anything better or about to be released, or should I go with another S9 Elite?