09-28-2017, 07:30 AM
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.
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.
