We have a week long houseboat trip planned for next summer. Both my wife and son are on CPAP machines and the boat specifically advises against using their power for CPAPS. My son and I both came to different solutions.
He bought a Jackery power station and the foldable 100 watt solar accessory. He used it on his Dream Station machine for a night and it drew down 8% of useable power.
I bought a Battle Born 100AH Lithium battery for our trailer and plan to install it in my MinKota battery carry case and take that. I will also take my 60 amp trailer charger with us to top off the battery if it gets low. Should take about an hour on the daily generator run. The case makes it easier to carry (32#) and serves an additional use for my trolling motor. We bought a 12V power cord from Amazon (around $40) and have tested everything in our trailer, works good. The battery was expensive but offers me many other advantages with the trailer. I didn't mind, can't put a price on health.