This is what you would need to buy if you want to couple a second battery to the power station
Go everywhere with your device
The Resmed Power Station II (RPS II) is an all-in-one external battery that enables operation of compatible Resmed devices where mains power is not available. It also provides back-up power in case of an unexpected mains power failure
Key features Include:
1.Provides convenient power without the need for a separate converter.
2.Ideal for travel, where power is unreliable, or when additional mobility is required.
3.Charges in less than four hours.
4.Features safety alerts and indicators.
5. Includes battery, power supply unit adapter and carry bag.
How it works RPS II is an external long-life, lithium-ion battery that works alongside ResMed ventilators or sleep therapy devices. Charging the battery: quick and easy You can charge the battery from 0% to greater than 95% in less than four hours. Power or backup power: simple and convenient The voltage output selector on the RPS II rear panel lets you select the correct output voltage for your device. Using the appropriate DC cable you can connect the battery to the ResMed therapy device to provide power or backup power. When providing backup power (for AC or DC inputs), the AC power cord connects the therapy device to the mains power outlet.
One battery will provide close to 14 hours of CPAP usage when using without a humidifier or heated tube at a pressure of 10cm H2O. The capacity of the battery drops significantly to close to 4 hours when using humidifier and heated tube. The capacity of the battery can be doubled by coupling a second battery to the first. in order to do this you need to buy the Resmed power station II and an additional battery and coupling kit.