Our home in NJ has a whole house standby genset that I installed in 2012. It has had a number multi-day runs after ice storms, Sandy and other severe weather events.
The longest outage we've had in our CYV in TV was last Thursday. Power went out at 4:15 and was back on around 6:15. Woke up and the clocks were off.
When we eventually move down full time, I'll get a Honda EU2000 inverter generator. They are whisper quiet and are plenty to run the fridge.
If we needed it for medical purposes, I would consider a Tesla Powerwall or one of those competitors. They use solar panels to charge and can give you days of power.
Our 14kw standby is pretty loud and since CYVs are on top of each other, it would probably annoy most of the neighbors, so I wouldn't do it just for that reason. Even the best enclosure will only mute the sound a little. Big generators are LOUD.
A Tesla Powerwall, Sonnen or LG chem backup are lithium batteries. They aren't known for noise during use
