Copyright © 2004, Pete Resnick
Last Updated: 7 April 2004
This is the story of how I found a battery for my CPAP device and how I got approved to use the setup on an overnight flight. Go straight to the bottom to see a summary of my setup. The rest of this is the details of the story which might help you if you want to find different equipment than what I got. This page will be updated as I get more information, as this story is ongoing.
(Skip this section if you already know what CPAP and OSA are.) I have been diagnosed with obstructive sleep apnea (OSA). This is the condition where during the night, you stop breathing for periods of time. One of the things done to treat this condition is to use a constant positive air pressure (CPAP) device. Basically, a CPAP device is a little air blower. When you go to bed, you put on a small air mask (or, in my case, a small set of tubes that go in my nose) that are hooked to the blower. This blows air in (at different pressures for different people) to keep you breathing. There are some links at the bottom to web sites with more info on OSA and CPAP.
I had a small problem using my CPAP: I travel a great deal for business, and occasionally I travel internationally on overnight flights. I wanted to be able to use my CPAP on the plane. This turns out to be tricky:
Now, unlike some folks, I had a few advantages in figuring out how to accomplish my task:
Here's what I ended up doing.
I have no relationship with any of the companies listed here other than being a satisfied customer.
When I first was diagnosed in 2003, it was clear that I was going to have to travel for my job with the CPAP device. So I did a little research to find one that I could easily pack in my carry-on luggage. At that time, Puritan-Bennett had just come out with a new, compact, CPAP device: the GoodKnight® 420G CPAP System. This device had two key features: It was tiny (5.6" W x 2.9" H x 7.7" L in or 14.2 cm x 7.5 cm x 19.5 cm, weighing 1.54 lbs or 760 g), and it had a 12 volts DC power adapter (part number M-213930-03) which plugs into a car cigarette lighter. I thought the latter would be good to plug into the seat power outlet if I needed to use it on the plane, but as I mentioned, the airlines won't let you do that. However, this turns out to still be a very important feature for my purposes, as you will see below.
There may be other CPAP devices that have these features (small size and DC power supply). I don't know about them; I found one that I liked and got it.
Finding the battery was the hard part. The CPAP device I had could run on 12 volts DC, but the specs say that it uses 20 volt amps of power. Talking to the folks at Puritan-Bennett, they said that this was the maximum power consumed. My CPAP device is set for a pressure of 9 cm H2O, which is on the middle to low end of the scale, so it shouldn't use all that power, but it was still going to use quite a bit. Not only that, it would have to last me at least 6 hours. Doing calculations (or more to the point, asking assorted folks who know more about electricity than I do to do the calculations), that's a battery that can support upwards of 120 watt hours of power. What kind of battery would supply that much power without being a car battery?
Well, it turns out that some companies make extra powerful batteries to power laptop computers over long periods of time. One of the companies that make this kind of battery, Valence Technologies, makes a battery called N-Charge. This battery comes in two models which are both the same size (11.8" L x 9" W x .5" H or 30 cm x 23 cm x 1.3 cm), small enough to fit in any bag or brief case. The higher-end model, the VNC-130, is rated to 120-130 watt hours of power and weighs about 2.97 lbs (1.35 kg). The lower-end model, the VNC-65, is rated to 60-65 watt hours and weighs 1.76 lbs (.886 kg). The VNC-130 clearly had enough power, and 3 lbs wasn't too heavy. (Note: I don't use a humidifier. A heated humidifier would probably draw too much power for any kind of battery.)
But how am I supposed to connect the CPAP device to this battery? Here's where I lucked out. The N-Charge is made for a laptop. Obviously a laptop plug won't fit the DC power plug of my CPAP device, and since the laptop plug is rated for 15-24 volts DC, that won't do for my little 12 volt DC CPAP device either. But the N-Charge has a accessory port. It's made to power 5-12 volt DC devices. And as luck would have it, in addition to plugs for cell phones and other goodies, Valence makes an auto adapter that plugs into the accessory port. That means that I can plug the cigarette lighter adapter from my CPAP device into the accessory port of the N-Charge.
Charging the battery was another interesting thing. Since the N-Charge is made for a laptop, the battery comes with an adapter based on the laptop you use. The adapter has a plug just like your laptop, both male and female. You are expected to use your laptop charger to charge the battery and plug the adapter into your laptop to charge the laptop. For me, I simply chose the adapter for Macintosh laptops since I already have a Macintosh laptop. Now, I could have used the charger that came with my Macintosh. But I didn't, and if you don't have a laptop, you can do what I did as well:
Some time ago, I bought a Juice power adapter from iGo. The nice thing about the Juice is that it is a single adapter with many plugs. On the input side, it comes with an AC plug to plug into the wall (which works for 100-230 volts AC), a DC plug that can plug into the airplane DC power ports, and a DC plug that can plug into a car cigarette lighter. On the output end, it has different plugs for all different brands of laptops. (It's got some other features too, but they aren't important to the CPAP story.) If you don't have a laptop, you can buy a Juice power adapter like I did, or you could by any laptop power supply (which would be cheaper) and get the N-Charge with the adapter that matches it.
This is not a cheap setup:
Puritan-Bennett's M-213930-03 cigarette lighter adapter for the 420G cost me US$60 at my local medical supply place.
On Valence's web site, the VNC-130 costs about US$300. (The VNC-65 costs about US$200 there.) The auto adapter costs about US$30. At MacConnection, I was able to find a package deal for the VNC-130 with a plug for my laptop and the auto adapter for US$259 (and at the time, I also got a US$10 rebate certificate), so it pays to shop around.
The Juice power adapter sells at iGo website for about US$120. I got mine from the local Radio Shack at that price because it was convenient. You can find it cheaper on the web (I saw it, again at MacConnection, for $99 including a cell phone adapter), and obviously you can find a cheaper power adapter than the Juice.
I first tested all of this stuff at home. First, I charged up the N-Charge battery with the Juice using AC power. That took about 4 hours. I unplugged the wall power, plugged the M-213930-03 cigarette lighter adapter into the 420G and the auto adapter, and then plugged that into the accessory port of the N-Charge battery. I set up to go to sleep. The next morning (7 hours sleeping), the battery was still showing between 40% and 60% full. I was able to use it for two nights without recharging! Now, that means likely I could have gotten away with the lower-end VNC-65 battery instead, but:
Airlines insist that you get approval for medical devices you bring on planes. American Airlines has a special services department that handles making these arrangments. They have a list of pre-approved medical devices and they can simply put you on the list for the flight as approved to bring on the device. Other devices have to be approved by their avionics department to make sure they don't interfere with aircraft systems. Once I had a reservation (and they need a reservation before they will make the arrangements), I called them up (800-237-7976) and asked for approval. I specifically asked for approval for my 420G and my N-Charge battery. (When I called, they initially said, "You can't use CPAP on a plane." When I asked why, they said because it needs to be on a battery, at which point I told them that I had the battery. Be polite, but don't take that first "no" for an answer; you're doing something new that they probably haven't heard of before.) They asked for model numbers and contact information for the companies that made the CPAP device and the battery. Be prepared with that information. They require at least a week for approval, but I got a call back within 2 days telling me that I was good to go.
I took my first trip yet with the CPAP device to Korea in March 2004. I took care of all of the permissions as noted above. Before the trip, I fully charged the battery and packed it and the CPAP setup in my carry-on. I had no problems going through security, and each time I checked in for a flight, the desk agent asked about "the medical device" mentioned in their computer system. Strangely, the flight attendants on the flight were not made aware of this. I did make a point to mention it to them before i set it up so that I wouldn't startle anyone. (Several asked whether there was oxygen involved.)
Once the seatbelt light was turned off, I set things up. (I was flying first class, so I had a bit more room to work with.) I put battery part-way under my seat. I plugged in the CPAP into the battery with the auto adapter and placed the CPAP machine on the console area between the seats. (My partner was sitting next to me, so that wasn't a problem. If you're alone in coach, the tray table may be your only choice.) I left the hose and interface in the bag and pulled them out later. And here's the cool thing: Remember that the N-Charge battery I've got is a laptop battery, and the Juice power adapter (which charges up the battery) has a plug that can plug into the airline seat power outlet. Therefore, I was able to plug in the battery to the airline seat power outlet. So, even though the CPAP device is running off of the battery, you can keep the battery charged using the seat power outlet. So, I've got CPAP device plugged (through the cigarrette lighter adapter) plugged into the auto-adpater of the battery, which is plugged into the power adapter which is in the seat power outlet. Quite the set of wires, but it worked fine.
And by the way: Sleeping was no problem.
Insurance companies normally don't cover batteries. I'm working on getting them to cover mine because it is part of my job to travel overnight. I'll give you updates on this when I find out what happens.
Here's what I've got:
I hope folks find this helpful.Pete Resnick