I have been using a CPAP for about 20 years.
When I was a Scoutmaster I use to take a little motorcycle battery with me. I canoed 50 miles down the Klamath River using the CPAP every night. I placed a little solar panel
on my tent during the day and it kept the battery charged for a little over a week.
Now days I use either my Jumpit which lasts 2.5 days, so I only use it for two days with out a recharge.
Or I use the Casita
house battery from the TV 12 volt outlet in the upper cabinet.
The new CPAP machines are so quiet, my wife can’t even hear it run a night.
If you have a specific question just ask. I hope this helps.