No sleep machine, but when my wife and I dry camped she ran the TV (CRT) all day long, battery powered, for something to do. In order to do this I did change from 2-6 volt golf cart batteries to 4. I rewired so I had two battery banks and only one bank working at a time. I also installed a larger solar panel to help maintain the batteries better. I only used the genset during meal preparation when the microwave was needed. By the end of day the one battery bank was down to maybe 60% and the other at 100%. The next day I switched to the full battery bank and started the process all over again, switching from one bank to the other each day.
I would think a CPAP machine would use less power than a TV (CRT), but haven't checked it out.
'99 Safari Trek, 2480, Frog Green with an Eagle on the back