ResMed AirSense 11 / AirCurve 11 DC/DC Converter (12V/24V)

The genuine ResMed AirSense 11 DC/DC Converter (Air11 — part 39231) powers your AirSense 11 or AirCurve 11 from a 12V or 24V DC source — cars, RVs, boats, caravans, and 12V/24V CPAP batteries. Plugs into a standard vehicle accessory socket (cigarette lighter), or connects directly to a compatible battery, and delivers clean regulated 24V power to your machine without dropping humidifier or heated-tube support. Genuine ResMed accessory — built for road trips, camping, off-grid stays, and home power-outage backup.

Key Features

• 12V or 24V DC input: Works with standard vehicle accessory sockets (cigarette lighter) in cars, trucks, RVs, caravans, and boats, plus 12V or 24V CPAP batteries.
• Regulated 24V output: Delivers the clean, stable power the AirSense 11 needs — protecting the machine's sensitive electronics from voltage fluctuations.
• Full humidifier & heated-tube support: Powers the device, HumidAir humidifier, and ClimateLineAir heated tube simultaneously — no need to disable humidification on the road.
• 2.4 m total cable length: 0.6 m vehicle-side input cable + 1.8 m DC output cable to the machine — plenty of reach in most setups.
• Compact and travel-friendly: Fits easily into a travel bag, RV storage, or CPAP travel case.
• Genuine ResMed: Manufacturer-specified part 39231 — designed and tested by ResMed for the AirSense 11 platform.

How a DC/DC Converter Works (and Why It's Better Than an Inverter)

A DC/DC converter takes the 12V or 24V DC power from a battery or vehicle socket and converts it directly to the regulated 24V DC your CPAP machine requires. This is significantly more efficient than the alternative approach — using a 12V-to-240V inverter, then plugging your normal CPAP power supply into that — because each conversion step wastes energy as heat. With a DC/DC converter, you skip the wasteful AC step entirely. The result: longer battery run-time, less power drain on your vehicle, and quieter operation.

Compatibility

For use with the ResMed 11-series platform:

• AirSense 11 series: AirSense 11 AutoSet and AirSense 11 CPAP variants
• AirCurve 11 series: all AirCurve 11 BiLevel variants

Common Use Cases

The DC/DC converter solves CPAP power in three common scenarios:

• Car, RV, caravan, or boat: Plug straight into the 12V or 24V vehicle accessory socket while you sleep. Modern vehicles' aux sockets are usually 12V; trucks and some marine setups are 24V — the converter handles both.
• Off-grid camping with a CPAP battery: Pair the converter with a Medistrom Pilot-24 Lite (using the AirSense 11 cable kit) or the dual-voltage Medistrom Pilot FLEX for nights without mains power.
• Home backup during outages: Keep the converter and a charged battery in your bedside drawer — if mains power fails overnight, switch over without losing therapy.

What's in the Box

• 1 × ResMed Air11 DC/DC Converter
• Vehicle-side input cable (0.6 m, terminates in 12V/24V cigarette-lighter plug)
• DC output cable to the AirSense 11 / AirCurve 11 (1.8 m)