Happy to report that I'm just using the emergency battery. I recharge it every day in the boat house and so it gets about 14 hours of charge between uses. It runs the machine all night, without flaw, and I'm not having to hook it to the ship's power.
I'll upgrade my ship's systems for other things besides this damnable machine, that I'm finally starting to get used to, short of the bruise, red spot in right between my eyes.
Getting a new mask fitted tomorrow that hopefully won't mark me up like the other.