A portable oxygen concentrator only works well for you, if the battery can last for as long as you need it to without needing to be recharged. Having the smallest portable oxygen concentrator you can get is usually also a high priority! As long as the portable model you want covers your oxygen needs, you shouldn't have to get a large one to have a lasting battery.
There are several portable oxygen concentrators in the small category (5 pounds and under) with batteries that have the ability to last for as long as 8 hours or more. Battery life of an oxygen concentrator battery depends on the setting, the higher settings it won't last as long, because it has to draw more electricity.
However, these small concentrator batteries will still last a lot longer than some of the others that are in the bigger size category. If you want a small oxygen concentrator with a long-lasting battery, you should check out these models.
Lifechoice ActivOx and ActivOx Pro 4L
The Lifechoice ActivOx and the ActivOx Pro 4L are two different portable oxygen concentrator models, but the ActivOx can only go up to 3 LPM equivalence, and the Pro 4L can go up to 4 LPM equivalence. The Pro 4L weighs just 4.8 pounds while the other only weighs 4.3 lbs.
The ActivOx Pro 4L only weighs 5 ounces more, yet offers 1 LPM equivalence more than the regular ActivOx. Another amazing thing about these two, is that with the internal battery can last for as long as 12.5 hours on the ActivOx, and up to 10.25 hours on the Pro 4L. You can add even more battery time to these by adding the external battery.
Inogen One G3 16 Cell Battery
The Inogen One G3 has two battery options, the 8 cell, and the 16 cell. It also only weighs 4.9 lbs with the 8 cell battery installed, but the 16 cell battery will only add 1 more lb, and double the battery life. If you need to use up to 750 ml/min of pulse dose oxygen and need a nice long lasting battery, the Inogen One G3 has you covered.
AirSep Freestyle with AirBelt Battery Pack
Don't need that high of a pulse dose? If you only need up to 498 ml/min, the Freestyle by AirSep offers this at just 4.4 lbs. The internal battery can only last as long as 3.5 hours on the lowest setting, but if you add the AirBelt supplemental battery pack, you can have up to 8 hours of total battery life.
AirSep has a couple different supplemental battery options, both of which add more battery life while only weighing about 1 lb extra. You can wear the AirBelt around your waste, and you just plug it into the concentrator.