's suggestion, after work yesterday I bought a portable battery charger with a 12V output, USB output, and battery terminal leads. Assuming it works, it should allow me to use my CPAP overnight even when (as right now) the RV's "hotel" power is offline. In addition, if I pull a mistake like I did at last year's BASFA outing to the San Jose Giants came and leave my lights on in the parking lot, this thing is supposed to be able to give the vehicle battery just enough of a charge to allow me to get the vehicle started so I don't have to wait around for an hour or two for AAA to come and jump-start me.
The battery claimed to have a full charge when I first opened the package, but I was skeptical, and indeed, I woke up in the middle of the night with the battery having fully discharged. This morning I brought it into the office and gave it a full charge. Fingers crossed that it has enough juice in it to run the CPAP all night, as breathing properly while sleeping acts as a multiplier on the rest I get. Current Mood: hopeful