My wife has late term emphazemia and is on oxygen 24/7. She has a 120 volt oxygen concentrator. We have numerous back up sources with 4 generators and several large bottles but in a fast power failure nothing ever goes right and she could pass out if alone. Is there some sort of battery back up system I could hook up to give her 5 or 10 minutes of power for the oxygen concentrator so she could breath while swapping over to a back up? I think I've seen sump pump battery back up supply. Anyone using something like this?