If you are active and need to recharge multiple Inogen One G4 batteries, an External Battery Charger can allow you to stay active longer.
The Inogen One G4 External Battery Charger is the ideal power source for recharging your additional Inogen G4 single and double batteries. Batteries can be fully charged outside the G4 unit in under 5 hours. A fully depleted G4 single cell battery can be charged to full in 2.5 hours and a fully depleted G4 double cell battery can be charged to full in under 5 hours. The charger includes an AC power supply.