I don't know if your electric company has a critical care program like we have in California, so you would have to check with them. With Southern California Electric “SCE” they have a program, where they will give you a battery backup for your home, if you are on oxygen, etc. They gave me a 3,000-watt battery backup. On top of that I bought 5 other battery backup generators from other companies.
I also have an Inogen G5 with 3 large batteries which would last me at least 24 hours.

Another thing is to see if you can get more oxygen tanks from your insurance. I get 12 E-tanks per month, and I bought an “Easy-Pulse 5+6” (you can get one of these through Wal-Mart) regulator to use with them, the regulator cost less than $250. With the regulator I can make one E-tank it last for 30 or more hours.

On an oxygen cylinder or home oxygen concentrator, a setting 3 LPM provides 3 liters per minute, or 3,000 milliliters, of actual oxygen output. However, the average breathing rate is 20 breaths per minute, or once every 3 seconds. Therefore, an oxygen user only inhales about 1/3 of the output, or 1,000 mL.

You can look at the attached chart to estimate about how long you could get on an E-tank.

I wanted to add to my question that I DO have an oxygen tank supplied by my provider, but I was thinking about something like a battery pack. I can't afford a whole house generator. Fortunately we have been lucky in this house and power outage are rare, but you never know when a weather event will leave you powerless. Just asking....Helene has me thinking about all those struggling without power.

You can get a huge tank that will last 48-72 hours I think. Don’t quote me. It will depend on what dosage 1 or 6 obviously.I have looked into back ups which they have .And ins Medicare downt pay for .