Operating CPAP with battery....

[Ulrika]

I purchased a battery for my Resmed so I can go camping and also as a back up if power goes out. This is the second night I am trialling it and exchanged the first one because it only lasted 2 hours but the new one has done the same thing!! Can I not run it with the heated hose? Surely an expensive battery like this one would run it for even half the time doing this... 2 hours before it keeps beeping is crazy. I have been to the website and checked out the manual but they are not useful at all.

[SuperSleeper]

Ulrika, what kind of battery did you purchase? What is it's "amp-hour" rating? If it doesn't have an amp-hour rating on the label, it's not the right kind of battery for use with CPAP. You're going to need one with at least a 60 amp-hour rating (or more - 100 amp-hour rating is better for more than one night).

For overnight CPAP batteries, (unless you want to spend big bucks) you almost always have to go with a 12-volt lead-acid deep cycle battery (these are about the size of a standard auto battery). They also make a hybrid "Marine starting battery" that can work for you as well, that are a cross between a car starting battery and a true deep cycle battery. These batteries are made to "deep-discharge" to a degree without doing major damage to the battery. "Marine" batteries are not as good as true deep cycles, but they will work, as long as the amp-hour rating is high enough. Most of the 12-volt "Marine deep cycle" batteries sell in the $60 - $90 price range, while true 12-volt deep cycle batteries usually sell for $150 on up, depending upon the make and model.

Here's links to other discussions on these batteries issues (good info):

http://www.apneaboard.com/forums/Thread-...pap-set-up

http://www.apneaboard.com/forums/Thread-...wer-outage

[trish6hundred]

Hi Ulrika,
You could use just a plain slimline hose rather than the heated hose and that should give you a bit more time on your battery. Just a quick question, did you get the Resmed Power station?
Anyway,if you experience rainout with the slimline hose, you could get a tube wrap or make one by cutting out the toes of old socks and sewing them together.

[Ulrika]

I posted this during the night so not very clear on details... it is a resmed Power station II - I purchased it from the place a bought my CPAP machine from and they didn't know much about the battery and we checked online and in the manual and it said less than 4 hours to charge and more than 8 hours battery time. I only got 2 hours the first night so they exchanged the battery for a brand new one that just came in, and that only went for 2 hours last night too! Yes I had heated hose and humidifier on but even then 2 hours is pathetic! They should give you the actual details for it - I am going to get a refund and buy a generator or solar panel system to use while camping or if power goes out I think!!

[SuperSleeper]

Wow, at $700, that ResMed power station II ought to clean your house, wash your dishes and take out the garbage too!

I like my rather inexpensive solution of the ResMed DC converter plus a standard deep cycle Marine battery and a simple 12 volt charger. Altogether I can use my system to power my CPAP for over 3 nights without recharging for less than $200. Yeah, a lithium ion battery is less weight of course, but if you're going to a camp site in a vehicle, a 30 pound lead-acid 12 volt battery isn't really an issue.

Looks like this ResMed power station is designed to run about 10 hours with no heated humidifier. Of course, it depends upon the CPAP unit's amp draw at a particular presure - the higher the pressure, the less battery time you'll get. Add a heated humidifier, and I'd bet that the run time goes down to about 4-5 hours, tops. Heating anything takes a lot of power. If you have a heated humidifier, you're not going to be able to use anything but a standard lead-acid deep cycle battery. This thing looks like it's designed for CPAP use without a heated humidifier.

[Ulrika]

Is there a risk of damaging the Cpap machine with a Deep cycle marine battery?? I don't care about weight... I just thought if the battery is good it would be easy to take on a plane if need be... but really I don't travel by plane much and when I do I have access to power anyway. Camping and power outage was my main reason so the battery could be an option too!!

[SuperSleeper]

There's actually less risk using a lead-acid marine deep cycle battery than using a Lithium-ion battery, assuming you keep the battery in an upright position.

The only issue with lead-acid 12 volt battery is that you're not going to be able to take it onto a plane. Heavy and has liquid acid in it (like a car battery).

For a ResMed S9 unit, you'll need three things:

1. 12-volt lead-acid Marine or deep cycle battery rated above 100 amp-hours [CCA or cold cranking amps rating is irrelevant for CPAP use]. (about $75)



2. A way to charge that battery (cheap 12 volt trickle charger, about $40, or some type of 12-volt solar panel charging system)


3. The ResMed S9 DC Converter and alligator clips (about $85)

[SuperSleeper]

Also of note: never charge your battery while it is attached to your CPAP machine.

[trish6hundred]

My husband Sam & I have always had trouble with deep cycle marine batteries. It seems like, no matter how hard we tried, even though they are supposed to be sealed, we still found that we had to put distilled watter in them to keep them from boiling dry.
For my Respironics machines, I got jellcells for them and they worked fine. I didn't know 'til I had boughten the Resmed Power station that I could just buy that supply with alligator clips on it and use that with my jelcells. Oh well, live and learn, (Ha-Ha-Ha.) I had just joined the forum a bit after I had gotten my S9 and the power station and wasn't totally familiar with things like this.

[Sleepster]

Even with the best battery, don't you have to turn off the heated hose and heated humidifier to get a decent life out of it between charging?