Great question that you bring up here, And I think it's not so much the brand as the battery size. The basic battery size for portable oxygen concentrators lasts about 4 hours on 3lpm. Although, how long they last may vary somewhat based on brand. If you're looking for something that lasts more than 4 hours, you may want to look into extended battery options. Many POCs offer a double battery, which can provide significantly longer use. For instance, with an extended battery, portable pulse concentratorsi can last 8-10 hours on a setting of 3. This can be especially useful for longer outings without worrying about recharging or changing batteries frequently. What do you think? John. community moderator.