Inogen is a reputable company, and at least they are supplying him with a new one each time the old one fails. I would probably go with third times a charm, and see what happens. After that, I think I'd be asking for my money back. Three lemons in a row is a little much!

A thanks he also has the G3 with no issues for 2 years. This must be a bug with the new model

I have the G3 and I have never had a problem with mine. I love that it is light weight and easy to carry.
I have had mine for 2 years.

I had the Inogen G3 (I was fortunate to have Inogen as my supplier and they had good service) and now I have the OxyGo. The Inogen had the problem of heating up and shutting down. Sometimes if I re-seated the batteries it recovered. You can run it in the car and take the batteries out for awhile. If you are forced to use a supplier that is not the manufacturer your service will be poor. Call Medicare and see what your options are.

I bought a new OXY GO 2yrs ago it has been in twice for breaking down on me it takes weeks to get it back they give me an other machine in the meantime along with a monthly bill.