The operational lifespan of an Inogen rechargeable lithium-ion battery depends on usage patterns, charging habits, and environmental conditions, typically lasting between 300 to 500 full charge-discharge cycles before noticing a reduction in maximum charge capacity. In terms of single-charge duration, a standard single battery can last anywhere from 2 to 6 hours depending on the flow setting, while a double or extended battery can last up to 13 hours on lower settings.