It is possible to use a CPAP machine while on charter. Our boats do have inverters so you would be able to operate a CPAP machine at night when plugged into shore power or the generator is running (only the Lagoon 450 and Saona 47 have a generator). Even on our boats that have generators (they aren’t always able to run all night) it’s a very good idea to bring a backup battery such as this.  It can be easily charged during the day so that it will have enough power at night.