Why do RV'ers run a 4000 to 7500 watt noisy generator when they need far than 100 watts of 110 AC to operate their medical equipment??? 40 watts of 110 AC/hr is typical or 22 Ah of 12VDC for 8 hrs. Even a 1000 watt Very quiet Honda generator would be 20 times what's needed and would use a tiny fraction of the fuel the big noisy generator gulps. Constant running generator noise is beyond aggravating especially the larger generators!
We have 3 generators for our 3 RV's and only run them for very short time lengths as our 5-7 deep cycle battery bank and our many inverters (300 watt to 2500 watt) is totally silent and will run a cpap machine for many nights including making our coffee and the useing the lights for days before needing a recharge. Then turn on the generator or the vehicle's engine using heavy gauge jumper cables (no 4 or larger wire) and recharge the batteries quickly and all set for more days. Small gauge wires recharge batteries very slowly with DC.
How do we know how well the inverter system works and for how long? Our 51 year old son uses one every night whether in their home or in their 5th wheel where it runs off a 300 watt inverter plugged into the bedroom 12V TV socket which is connected to the 2 Group 31 12V deepcycle 5th wheel batteries and it lasts for 3-4 nights before a 50% battery discharge. He uses LED lights to illuminate the RV interior at night and they don't draw squat.
