If your road trip with CPAP begins with a flight to pick up a rented RV or motorhome, the airline might not let your home battery on board. Here’s why.
Why Your Home CPAP Battery May Not Be Allowed to Fly
Many portable power solutions and larger CPAP batteries that people buy for camping and motorhomes hold well over 200 Wh.
A battery like that works well when you drive to every site, because it never goes near an airport. However, it cannot travel with you if you fly out to collect a rental motorhome or RV instead.
This trap catches people out, because the big battery is exactly what they would want for a trip off grid. For the wider picture of flying with a CPAP, see my CPAP travel guide.
What the 100 Wh and 160 Wh Limits Mean
Airlines judge lithium batteries by their watt-hour rating, which the manufacturer prints on the battery’s label. Under the FAA’s lithium battery rules, which match the international rules most airlines follow, batteries fall into three bands:
- Up to 100 Wh: allowed in your carry-on without airline approval.
- Over 100 Wh and up to 160 Wh: allowed in your carry-on, but only with the airline’s approval.
- Over 160 Wh: not allowed on a passenger flight at all, in carry-on or checked bags.
A spare battery must also travel in your carry-on, because the rules ban spare lithium batteries from checked bags. In practice, any battery over 160 Wh has to stay at home. While one between 100 Wh and 160 Wh needs airline approval first.
My post on CPAP battery rules for flying covers this in greater detail.
Do You Need a Big CPAP Battery in a Rental RV or Motorhome?
Usually not, because a rental motorhome or RV already has its own leisure battery, which Americans call a house battery. Moreover, many of the sites you would book on a touring trip offer shore power, also known as electric hookup.
On electric hookup, your CPAP runs from an outlet just as it does at home. Off hookup, a CPAP with the humidifier off uses far less power than its label suggests. Therefore, a modest battery can often cover the night.
Before you book, ask the rental company how big the supplied leisure battery is, and whether the living area has 12V outlets. That way, you know whether you can run your CPAP from the vehicle with a DC cable or converter.
My post on using a CPAP in an RV, motorhome or caravan explains hookup, leisure batteries and overnight power use in more detail.
What to Pack for an Fly+RV CPAP Road Trip Instead
The simplest kit is a CPAP battery under 100 Wh, because it falls within the standard airline limit without any approval. You can then top it up from the vehicle or hookup as you go, so it only has to cover a night or two at a time.
Pack the DC cable or DC/DC converter for your machine as well, since it lets you run the CPAP from the vehicle’s 12V outlets. However, ResMed states that its converters are “not intended for use on an aircraft,” so keep yours packed until you reach the vehicle.
If you genuinely need several nights off grid, it is easier to buy or rent a larger battery at your destination than to bring one from home.
Finally, keep your CPAP and battery in your carry-on, and use my free printable CPAP luggage tags to mark the bag as medical equipment.
Does the Same Apply to a Fly-Cruise?
Yes, because the battery has to clear the airline before it ever reaches the ship. Therefore, a battery over 160 Wh cannot come with you on a fly-cruise, even if you only plan to use it on board.
Cruise lines also set their own rules on medical equipment and non-surge protected power strips. So check with your cruise line before you sail.
