When the DME brought me my CPAP last Friday, I made sure that he saw my emergency backup battery and cleared it with him for use. I did a test run last night, and was able to use BOTH the CPAP and the humidifer all night on battery backup.
While Pittsburg is in the same country, I will still bring the backup battery, in fact, I might very well use it on the plane -- I did call and clear it even though the person I talked with said -- it's not a night flight so you don't need it and I didn't contradict her.
Anyway, I'm thrilled it works well with the new machine. Primarily because it cost over $250.00 I haven't used it much -- in two power outages locally and when I tried to go to Monte Carlo. There were plenty of times I wanted it before I bought it, so it's been a good purchase. I try to remember to take it on trips, since once when I went to Austin they had a power failure and I ended up driving home instead of waiting for the power to come on -- I did wait an hour.