Curious; so I just checked the specs on the DW's PD Dialysis Cycler and CPAP machine.
Cycler - 600 Watts Peak - 100 Watts Average (9 hours run time per night)
CPAP - VPAP II - 200 Watts w/o Humidifier (Have an "un-powered" humidifier Respironics REMstar Passover Humidifier
The cycler's fluid heater use can be "moderated" by setting up the machine while on generator so the fluid can be pre-warmed before switching to battery for the night. That way the cycler will be in the "100 watt" mode all night. (whoot)
With 150AH bank (2 - DC-24 DeKa Marine DP) and a 1000 Watt inverter, I might be OK with no heater use.
Looks like the Deka's will be moved to the basement to augment the sump pumps and a couple of true Deep Cycles are in my future.
Come ON, Christmas!
The math (Camaradie Please check the logic!) ...
25 amps required for 300 watts - shared between 2 75 AH batteries
12.5 amps per battery required for 9 hours = 112.5 amps per battery per night.
Capacity reduction 30% (from chart) so 52AH available per battery
So, (If I understand what Camaradie is saying correctly), the battery should deliver 52 amps over a period of 20 hours or 104 amps over a period of 10 hours (114.4 amps over 9 hours).
With my two batteries it looks like a close run thing.
3 batteries or just 2 bigger ones?