Battery backup for PRS 560

I composed this before I saw the thread from Chrisinfp. I PMed him this but did not post it as a reply because I did not want it to get buried.

My wife and I use PRS 560 machines which run on 12 volt DC. The humidifier is easily detached and the "blower" works without the humidifier. I wanted a convenient battery power that would meet backup needs at home and travel capability for example on an airplane or train or camping. There are many threads that discuss backup and portable, rechargeable systems. I decided on the PowerAdd battery (thank you Jagzoo for your help) and purchased two. During my reading, I didn't see a compact example of what I might expect in my situation. So the following table shows the initial results that I experienced. I took the battery out of the box, connected the power cords and fully charged it (probably about 9 hours). With no cords plugged in, I turned it on and switch the output voltage to 12V (the default is 9V, I think). When I went to bed, I connected the cord to my CPAP using connector tip J, then connected the other end to the battery, the CPAP turned on (not the blower yet). I put on my P10 headgear, My min pressure is 7 with no ramp. Connected to the tubing, the blower came on and I went to sleep. In the morning, I turned off the blower, unplugged the cord from the battery and went about my business. Other than no humidifier, which does not bother me, I noticed no difference than on house power. I repeated the process for days 2 and 3, disconnecting the battery each day. The results are below. I repeated the process for battery #2. I might have been able to get a fourth night but I saw no need to try. The recharge time for each was about 6 hours. The recharge times are inexact because I tried to observe when it said 100% charged. I hope this helps others who might want to make a decision.

________ Pressure___Pressure__Power-Level__Power-Level
On-time__Average_____Range_____Begin _______End
Battery #1
6:37:24 ___7.82______7.0-12.4_____100%_______ 76%
5:48:01___ 8.10______7.0-11.5______76%_______ 54%
5:53:04___ 7.54______7.0-10.0______54%_______ 32%
Battery #2
6:03:24___9.78______7.0-13.0______100%_______ 75%
6:02:43___8.62______7.0-11.5______ 75%_______ 52%
5:44:27___7.69______7.0-9.1_______ 51%_______ 29%

Sorry about the underlines but I couldn't figure how to format the table.

Which PowerAdd battery did you buy? -- Jim

Jagzoo, the member that he thanks, and I both use the Poweradd Pilot Pro 32000mAh. With my bilevel pressures of 15 Ipap and 11 Epap, I can get 2 nights with my battery.

Lithium batteries are much different from other rechargeable batteries. With lead acid, nicad
or nimh batteries they like to be left fully charged and last a lot longer like that. But lithium's
deteriorate much faster if left fully charged which is the reason when you get anything with
a lithium battery it says charge before use. By shipping them with only about a 40% charge that
battery will still be almost factory fresh if not sold and used for a couple of years. But just keep
your new laptop pluged in to the ac adapter and your battery will usually be dead in 2 years.
So if you buy one of these batteries it might tbe best not to recharge it after that camping trip
but wait till the day before you leave on your next trip.

jim22 wrote:Which PowerAdd battery did you buy? -- Jim

I also bought the Poweradd Pilot Pro 32000mAh.

I thought I would provide an update to my original post.

Last week, I used the batteries which had been stored in their boxes fully charged (100% reading) for about two months. I wanted to understand the likely-hood that they would work when I needed them when pulled from storage. Both delivered two nights with average sleep time of 7.1 hours, average pressure 8.8 and average 90% pressure of 10.9. I removed the humidifier so it was just a blower in APAP mode.

_______________Start_______End
Battery #1
Day 1___________91%_______ 65%
Day 2___________65%_______ 36%

Battery #2
Day 1___________87%_______ 52%
Day 2___________52%_______05%

The start and end percentages are the readings on the battery upon going to bed and awakening. So my conclusions are to store them charged and pull them out every couple of months, use them for a couple of nights then store them. I am confident that they would to "survive" an overnight power outage comfortably. They are also small enough to use for travel.

I hope this provides a non technical assessment of battery backup.

Thanks for the info, On the virge. It's useful to know that it works, and good to see that you can easily get a couple of nights out of one.

Keep in mind that lithium ion chemistry differs from lead acid chemistry in that lithium ion batteries degrade when stored at 100% full. Ideal storage is 40 - 50% full, but that doesn't offer much use. A sweet spot seems to be around 80% full. This gives you some use and also reduces the damage done by storing at 100% full.

An ideal set up would involve a lead acid battery for back up at home, and a lithium ion battery for use when camping. The lead acid would be kept at full charge. When in storage the lithium ion battery would be stored at 40 - 50% charge and charged to full before going camping.

An alternate is to keep the lithium ion battery at 80% for possible power outages and then fully charge it prior to going camping.

To keep perspective on things, a lithium ion battery stored at 100% charge will show reduced run time after a year or two of storage. Another alternative is to store it at 100% and plan on replacing it every two years.

HoseCrusher wrote:Keep in mind that lithium ion chemistry differs from lead acid chemistry in that lithium ion batteries degrade when stored at 100% full. Ideal storage is 40 - 50% full, but that doesn't offer much use. A sweet spot seems to be around 80% full. This gives you some use and also reduces the damage done by storing at 100% full. To keep perspective on things, a lithium ion battery stored at 100% charge will show reduced run time after a year or two of storage. Another alternative is to store it at 100% and plan on replacing it every two years.

Thank you HoseCrusher. I have already stored mine but perhaps, I'll run them for one night then store them, wait a couple of months and pull out of storage and see the results. If I do this then I will post back to this thread.

Looking back, I see that Woody had similar advice. It didn't register with me the first time because I really am no longer into camping but wanted the backup feature. To me that meant I needed to have it ready to go at times not of my choosing hence substantially charged.