I have the heavy duty battery on my Inogen unit and at 4ltrs pulse it will last six-plus hours. On 3ltrs, eight hours.

yes they do have continuous flow now you have to look for them or call supplier

Hello, so currently the highest available flow rate of portable oxygen concentrators in terms of continuous flow is 3 liters per minute. If you need a higher rate of continuous flow you would need a home oxygen concentrator. It's important to understand that a pulse flow of 4 does not equate to a continuous flow of 4 liters per minute. :)

I would think that having a continuous flow on 4 ltrs would run out a battery pretty fast unless you were able to plug it in. I run mine on 3 ltrs on pulse and it only lasts about one and half hours on one battery.

Inogen.