I've had the Rolling Stone for just short of two years now. It has long since paid for itself in savings over hotel stays. (It took about 14 months, probably less because Bay Area hotel prices have been going up at least as fast as apartment rentals.) But there are maintenance costs, and we're on the verge of one of them. The RV has two batteries: one is for the engine like most vehicles, and the other is for the "hotel power" including interior lights aft of the driving compartment, the water pump, and in particular, the power supply for my CPAP. (My CPAP runs on both 100-240V AC and 12V DC, and I have all of the necessary plug adapters. I don't have to rely on an DC-AC inverter, thank goodness. And I've run the gamut of voltages, including Japan, Australia, and Europe.) We bought a pair of deep-cycle RV batteries for the Stone when we bought it, but the "coach" battery is showing its age now. Despite the fact that I have to move each day and therefore am putting some more power back into the battery, by the end of a two-week stay, it cannot keep the CPAP running overnight. I woke up at 3:30 AM to the sound of the alarm on the machine and it flashing the "not enough power" warning. I disconnected it and went back to sleep.
Our plan is to trade out one of the batteries in the Big Orange Van (it also has two batteries), replacing it with the coach battery from the Stone, then use that removed battery from the BOV as the trade-in for a new deep-cycle RV battery for the Stone. Lisa's van doesn't have as deep a draw on the auxiliary battery as I do, so this should work out for the best.