I have a 120vac CPAP machine which is 15 years old. It draws 2A for the blower and 2A for the water heater. I do not have an inverter in my new Lance 1040. What make and model of CPAP machine op...
I've got a ResMed S9 CPAP with the humidifier and it works fine in my Northstar 850SC when plugged into the 12V plug. I have one 80W solar panel on top and it seems to recharge the batteries by mid-morning if the sun is out.
This will be my second season of owning a camper, it has been so nice to be able to sleep well at night.
I second the reference to cpap.com, you will be able to find all the accessories you need there.