battery

There is probably info on this, but am new to CPAP's and these forums. I have a Philips Respironics REMstar Auto A-Flex and am going to need a battery that will last about 2 weeks for camping that I can carry around. There will not be power available to recharge. Is there such a beast?

It depends on how strong you are, we use one to start heavy equiptment, but they each weight 100 lbs. Jim

I read somewhere that Somnetics company got an award for innovation of a solar-charging battery pack
for their Transcend travel CPAP.
No idea when it will be available. Doubtful it will work for your machine.
That much time would require a BIG battery--Can you get a spare Prius drive battery?

I would recommend you look into a mouthpiece to help keep your airway open. There are several that might help reduce your apneas to a bearable level. You simply won't be able to carry enough battery power for that amount of time. Sorry.

Solar charger ( boat section ), 12v 110V battery back up ( automotive section ) from wally world.

To really work this out accurately, you will need to calculate (or measure) what the current draw of the CPAP machine is during your normal operation for your settings....higher pressure settings, higher humidity settings etc. will all use more power. If you cut the humidity etc, that will reduce it a lot....but how much...I don't really know. Has anyone measured their CPAP machine current/power draw at 12V?

Easily done on AC power with something like this:

http://the-gadgeteer.com/2007/07/20/kil ... e_monitor/

After you have the current draw for the machine at YOUR settings, we could calculate how many Ah (Amp-hours) your machine will draw nightly (based on your hours of use), and then go from there....

But that said....realistically, even if you machine was only drawing about 1.5 amps (little less than 18w of power)...and I think these machines draw MORE than that, for 14 nights, at 7 hours per night, that is 98 hours x 1.5 amp or roughly 150Ah. So, given a 100% efficient battery that will provide you the full 12V power the entire time, you might be able to get away with a 150aH battery.

But, realistically, you can't run the battery down completely as 1) it will ruin the battery, and 2) it will provide a lesser voltage to the CPAP machine as it discharges, and I do not think you want to "fry" your CPAP machine by running it at LESS than 12v (I don't know the acceptable voltage rating of CPAP machines...), so if we added 25% to the aH to add some space, you are up to around 190aH....so let's say a 200aH battery may suffice (again...assuming a very low 1.5Amps draw).

In that range....you are looking at around 65kg, or around 143 pounds....

Hope you are not back-packing!

(note...I could have easily screwed up the math....my electronics are a bit rusty and this was based on many assumptions)

Grant

sbwimb wrote:There is probably info on this, but am new to CPAP's and these forums. I have a Philips Respironics REMstar Auto A-Flex and am going to need a battery that will last about 2 weeks for camping that I can carry around. There will not be power available to recharge. Is there such a beast?

You did not mention if money would be an obstacle?

For 2 weeks eh? IF you go w/o will you get cranky?

Maybe you should stay home? Or order an air drop.

You said camping, in one spot or hiking all day and then setting up camp? If you are camping in one spot yes you could use a small battery and solar panels. If you are hiking and camping at the end of the day then that would be tuff.

Albert

In a post I put up about respironics battery back, I found a possible solution. Try this thread and look at the solar chargers and battery packs.
viewtopic/t76933/Respironics-battery-pack.html

Gerry