CPAP machine and batteries

We have 2 six volt AGM's, 220 amp/hrs. We run 2 CPAP's from a small 300 watt inverter. We can watch a movie every night and run the CPAP's all night without going below 50% on the batteries for 3 nights in a row when boondocking in reasonably warm weather. We have 200 watts of solar. If we have to run the furnace, there is still plenty of power for one night. Solar and/or driving will usually charge us back up the next day. I have installed switches for the propane and CO detectors and only turn them on to check periodically which is probably why we get by so easily. I'm NOT recommending that you do that unless you're willing to take the responsibility for your own safety. Hope this helps. -Mark.