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Backup power options for CPAP machines
Backup power options for CPAP machines
There have been a number of threads addressing backup power options, but all that I have read seem to be incomplete.  Since I have been researching and using various options for almost six years, I thought I would provide my highly biased views on this topic.  My research has been focused on my ResMed S9 machines, but most of this information would easily apply to other brands.
Short of an emergency generator that starts automatically when the house power goes out, the ideal solution would be to have some sort of backup power supply such as an APC UPS.  Determining the size can be a bit of a challenge.  When I first contacted APC, they were not willing to help claiming that their products are not designed to be used with medical equipment.  I tried to reason with the technical representative that the UPS does not care what it is that is drawing the power, that it will work as long as it is not overloaded.  When that did not help, I finally just asked what UPS unit would be recommended for a hypothetical load of 110 watts for seven hours (without identifying exactly what that load would be – this is the maximum power consumption according to the ResMed specification; this is probably an over-kill since the typical power consumption is listed as 70 watts).  From this, there were a number of recommendations that ranged in price from $1000 to $1500.  Any of these would definitely have solved the problem.  If my house were to lose power immediately after falling asleep, I would easily be able to get my normal six hours of sleep using the heated humidifier and with CPAP airflow maxed out.  The drawback to using any of these options is that they are all large, heavy, noisy (when in backup power mode) and of course, expensive.  I had been using an APC Smart-Ups 1500 that I was using and no longer needed for a different purpose.  Although I knew it was not enough for an entire night, it would at least provide power for an hour or so (better than nothing).  That unit is noisy when in backup mode (although usually not enough to wake me up) and the larger ones are much worse.  Plus, it is not practical to travel with something so big and heavy.
The next option I considered was the ResMed Power Station II (RPS II).  This system is specifically designed for use with the S9 and S10 models.  Since this is made by the same company that makes my CPAP, it seemed like a good choice.  It uses a lithium battery which makes it quiet and easily portable and supposedly will last up to 13 hours (in this case, only if the heated humidifier is not used).  In my case, it would likely last about four hours at best due to my high pressure requirement.  But a second battery can be added to double that run time.  The two batteries plus a cable to connect them will cost about $1200.  However, it really can NOT be used as a backup power supply.  In other words, you can use your normal ResMed power supply OR the backup battery (or, batteries as the case may be).  There is no way to configure this to use household power and then automatically switch to battery power when the need arises.  Therefore, the only time one would really use this would be if there is no power, or it is highly anticipated that power will be lost, in which case you would simply hook up your CPAP to the battery.
There are at least two other lithium battery options that actually provide true backup power:
Freedom Travel Battery Pack and Medistrom (Pilot-24 Plus for ResMed or Pilot-12 Plus for others).  The cost for two batteries and necessary accessories for each are about the same ($500 or so).  Either of these can also be used with other brand CPAP machines.
My preference is the latter, but first I will discuss the Freedom system and why I don’t like it (in fact, I actually purchased this and returned it unopened after carefully reading all the details).  This is a 12 volt system with its own power supply.  In order to use it with the ResMed, you also need a 12 to 24 volt converter.  Plus, the cable used to connect the two batteries together needs to be purchased from a different company.  The worst part of all is that there is no alarm to indicate when the battery has been drained (at least that was the case as of December, 2016).  The obvious consequence being that you either wake up gasping for air or you die (perhaps the concern is not that significant for those who have a relatively low pressure requirement).  Plus, in my case, I have an extra S9 power supply that I use for travel.  So, I would have to purchase an additional Freedom power supply to maintain my current convenience.  I thought this was rather hilarious, but one reviewer actually recommended buying a device that sounds an alarm when the house power goes out (duh, really, so what would be the point of having the backup batteries only to be alerted when they kick in but not after they are drained?).  The use of such a device only makes sense if one is not using any backup solution.
One small advantage of the Freedom system is that the accessory for using one’s automotive plug-in is inexpensive compared to the same for the Medistrom Pilot-24 Plus which requires a 12 to 24 volt converter.
The Medistrom uses the ResMed power supply as its charger.  It also has an alarm that sounds when the primary battery is drained (but not when the secondary battery is drained if using two batteries).  One website reviewer actually complained about the alarm.  Well “Hello Buddy, do you really want to deal with the possible consequences”?  Another reviewer complained that this product is not UL listed.  That is because it is manufactured in Canada which meets other certified standards.  Although there have been many reports of lithium batteries burning or blowing up, I have not seen a single such report of a Medistrom battery having this problem.
Another nice feature is that you could hypothetically have unlimited backup power in case of an extended power outage (e.g. more than a day or so).  Simply purchase extra Co-Pilot batteries for about $175 each and have then charged and ready to use.  The Freedom batteries may be able to do this too, but I have not investigated that option for that brand.
There may be other options and folks are welcome identify those if desired.  I personally have not investigated any others.
A few cautionary notes are in order regarding the Medistrom option.  Be very careful to follow the assembly instructions exactly as listed in the user manual (especially when using two batteries).  The electronics seem to be a bit sensitive in this regard.
Also, during one of my communications with a Medistrom technical support representative, he asked what model CPAP I was using along with the pressure settings.  When I replied that it is a ResMed S9 Vpap ADAPT at 16 to 31 cmH2O, I received this response:
[… ASV units aren't supported for use with the Pilot-24 Plus due to having stronger compressors to treat more severe sleep apneas. The Pilot-24 Plus was designed for use with standard CPAPs, BiPAPs, and APAPs and has protection circuitry built in to detect under/over current. If triggered, the battery will alarm and produce an irregular sounding audible alarm.]
By the way, the normal alarm that sounds when the battery is drained is a regular sounding beep, like an alarm clock.
I could not find this disclosure explicitly documented anywhere.  Here is the exact wording on the Medistrom web site regarding the Pilot-24 Plus:
“Compatible with most CPAP, APAP, and most BiPAP devices on the following platforms: ResMed AirSense 10, ResMed S9.”
Perhaps this is an implied disclosure.
It is worth pointing out that one night I accidently used my S9 VPAP Adapt with just the Pilot-24 Plus battery with the heated humidifier and heated hose enabled (a specific scenario that is NOT recommended by Medistrom) and it lasted about 2.5 hours before it was drained and the alarm sounded.  It would seem reasonable to conclude that two batteries would give me about five hours of uninterrupted sleep.  I could definitely live with that.
After discussing this further with the rep, he said the concern is not really the constant current draw (such as with the heated humidifier), but rather the spikes that could occur when a pressure requirement increases suddenly (as with an auto-titration machine such as my VPAP Adapt).
Considering the tradeoffs, my preference is definitely that from Medistrom with two batteries.  I’ll take my chances with the supposed incompatibility.  The worst case scenario would be that I am awakened by an alarm.
However, something is better than nothing.  For several years I used an APC UPS 500.  Although it only provided about 20 minutes of backup power, at least it got me through the typical power glitches that occur during thunderstorms and other types of inclement weather.  It only weighs about 20 pounds and I would often bring it with me when I traveled.  A remanufactured one can be purchased for less than $50.  Important note:  All APC UPS units come with an alarm that sounds when the power goes out (i.e. when it switches to backup mode).  This alarm can and should be disabled (the default setting is enabled).  It also has an alarm when the battery is drained.  That should not be disabled.
This should not be necessary, but I feel compelled to make a pre-emptive comment to the fact that I am in no way whatsoever working for or being compensated by Medistrom.
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RE: Backup power options for CPAP machines
For completeness, I wanted to add some info on a Respironics battery designed for their newer machines (such as the DreamStation). It's a compact and elegant solution.


That link should be OK since it's directly to the manufacturer's website.

You take your Dreamstation power supply and plug it into this battery. You take the battery output and plug it into the Dreamstation machine. Under normal operation the battery simply passes thru the power. When there is a power failure the battery takes over and provides power to the machine.

Some problems at first glance:

1) the battery is relatively low capacity, so that it meets FAA requirements. So it doesn't do well with humidifiers.

2) it's bloody expensive. I've seen prices online in the $600 range.

3) warranty is only for 6 months.

But it is a solution from a medical device manufacturer. So I'd feel a lot safer with that then with some random junk bought from Alibaba or fleabay.
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RE: Backup power options for CPAP machines

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RE: Backup power options for CPAP machines
Thanks for the info eplantz.  The ECOFLOW RIVER is effectively an APC UPS with a lithium battery instead of wet-cell battery.  Something I have been trying to find for many years.  Yet, this unit does so much more with all of those other outlets.  Hopefully, they will soon make one with a bit more capacity.  It is not quite enough for what I would need.
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RE: Backup power options for CPAP machines
(09-29-2017, 07:15 PM)terp1984 Wrote: The ECOFLOW RIVER is effectively an APC UPS with a lithium battery instead of wet-cell battery.

There's one big difference between a standard UPS and this RIVER.

In normal operation an APC UPS passes its input AC line voltage directly to its outputs. It only switches to its battery during a power failure.

This unit can't do that, since it only takes in DC. So you're constantly running off the battery. That means only 500 days of battery life if you use this every night. Not so great for daily use.

Still, it looks like a fantastic product for campers etc. It's even a great product to break out of the closet and use at home in case of a power failure. It just isn't suitable for daily use. Unless you want to wear the battery out, you can't stay plugged into it every night.
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RE: Backup power options for CPAP machines
For the cost, I could get ten 35 Ah AGM batteries. Yes they are heavier, but every bit as capable and I would get 350 AH as opposed to approx 33 Ah capacity from ONE of these.

In the case of ten 35 Ah batteries, that's almost 80 days of CPAP use without ever thinking of charging.

Then again, I do quite nicely on my homebrew CPAP UPS that consists of a 35 Ah battery, a powergate/charger (West Mountain specifically-the Astrons powergates don't have true smart charging capability) and a commercial power supply. If power fails while using heated humidification, no problem. Automatic switchover to big battery if power mains drop, returns to mains as soon as they come back online and automatically recharges/maintains the battery. User never knows power dropped caus they sleep through it. I have 3-4 full nights capacity without doing anything. Of course, as soon as I realize power is off, I would shut off humidification and that would get me probably 5 more nights on that battery. Then switch to another spare for 8 nights. All rigged with Anderson PowerPoles for easy, rapid hookup.

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RE: Backup power options for CPAP machines
Re: Medistrom Pilot-24 Plus for ResMed

How long will the lithium battery last? Is it replaceable? I couldn't find any information about that. With the APC units I have used for computer equipment we could swap out the batteries every 4-5 years. I wonder what happens when this lithium battery wears out.
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RE: Backup power options for CPAP machines
According to the Medistrom documentation, the batteries can be recharged 500 times.  if not used, the implied shelf-life is indefinite if recharged at least once every six months.  So in that sense, one could say the batteries will last up to 250 years.

Regarding replacing only a battery, I could not find such an option, but since the battery cables only cost about $20, there would not be much of a savings anyway even if you could buy just the battery.
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RE: Backup power options for CPAP machines
(10-02-2017, 12:25 PM)terp1984 Wrote: According to the Medistrom documentation, the batteries can be recharged 500 times.  if not used, the implied shelf-life is indefinite if recharged at least once every six months.  So in that sense, one could say the batteries will last up to 250 years.

Regarding replacing only a battery, I could not find such an option, but since the battery cables only cost about $20, there would not be much of a savings anyway even if you could buy just the battery.

<terp1984> Thanks for the information. It looks like a good backup source.
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RE: Backup power options for CPAP machines
Hello and greetings from Australia.
Not sure how relevant this is but we had a power outage last night and it got me thinking about a back up machine and a back up power supply.  I decided to purchase a BMC Luna 3.5 Auto machine  (3 year warranty), plus its accessory being a Luna 4 night battery (A$450).  This battery pack runs the BMC Luna machine and provides UPS functionality that will automatically switch over from AC power to DC battery power without interruption if you have a power cut during the night. Unlike most other cpap devices they say you can run the BMC Luna with the humidifier using this battery(for a shorter time - see below).  They state patient tests running machine at a constant pressure of 10CMH20 with no mask leaks showed -

3-4 night run time without humidifier (26 hours 40 minutes)
Run time with humidifier set at mid-range - 6 hours 41 minutes
Battery charge time from flat - under 5 hours
battery weight - 1.1 kg
Battery Spec 24DC, 150WH
This seemed to fit my requirements as I can charge it with my 1 KVA petrol generator during the day during a power outage.  Can also use the machine while caravaning without power. There is also available a mobile power adaptor to run the machine from any 12V DC source such as a vehicle lighter socket.  This provides a further back up option for me so I put an order in for the whole set up.
Time will tell how it performs.
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