Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

Comparing old battery to new - Something I forgot to consider
#1
Comparing old battery to new - Something I forgot to consider
I was going on a four day canoe trip and knew my single three year old battery was not going to last that long.  I generally got two nights out of it when new but it had reduced to not being able to give me two full nights anymore, just one and a fraction.
 
I have the old Medistrom Pilot 24, no longer available, so I got a Medistrom Lite.  I figured it would give me two full nights and the older battery would give me one full night and some fraction of another.
 
Well when I went camping things didn't work out as expected.  The old battery gave me one full night (and then I used the remainder to charge my phone).  Then I switched to the new battery and it behaved about the same as the old.  I  didn't buy the battery at my local CPAP store because the prices there were over 10% higher than buying online.  They refused to price match so I got it online (pricing is already crazy enough online without tacking on another 10%).  Then on the trip when it conked out early I figured I had been sent a dud and now I was kicking myself over the battle I saw ahead of me getting a refund from an online company.
 
I reviewed my times at home and saw the new battery gave me 11:13 operating time on the trip.  I thought maybe I hadn't fully charged the battery or something, so I made sure to fully charge it and tried it again at home.  This time I got 11:15.
 
Then I started checking this board and it twigged me to the important fact I had forgot:  When I initially started using CPAP I was set at 7 cm H20 and that is how it was on my first canoe trip when I got the two full nights (I actually started on CPAP two days before the trip).  Then soon after I was moved to a new setting of 9 cm H20.  I didn't go camping again till a full year later and that is when the run time on the battery sunk below two full nights.  I attributed this to the aging of the battery.  But I realize now the real issue was the increased pressure.  I recharged my new battery again and then went for two nights at home using a value of 7 cm H20 again and the time I got increased to 13:22.
 
So that was the answer, the new battery was good.  I just wasn't accounting for the increased pressure I have been on for the last three years.  I checked against this Resmed document and it says to expect about 10:20 at 8 cm H20, so I am right in line with expected performance on the battery (leak rate would account for some of the variance).
 
https://www.resmed.com/us/dam/documents/articles/198103_battery-guide_glo_eng.pdf
 
Anyways the takeaway for me in all this is:  when going camping, temporarily lower pressure on your machine to get the run time you need.  I would rather run at a lower pressure for 100% of my sleep time than at full recommended pressure for less than 100% of my sleep time (and so do the rest of the people in the tent).  Of course the amount you should reduce is limited by the resulting increase of AHI.  For me dropping from 9 to  7 in my testing resulted in no significant increase in AHI value (but of course this is only data for a few nights).
 
 
And one thing I don't like on the new battery model vs the old:  The old battery starts beeping continuously when charge gets low, and wakes you up so you can turn off the CPAP machine.  The new battery just gives a tiny single quiet beep that won't wake you up and then shuts off, so you wake up not getting air thru the hose.
Post Reply Post Reply






Donate to Apnea Board  
#2
RE: Comparing old battery to new - Something I forgot to consider
The easiest and cheapest is to make your own pack out of li-ion 2170 cells, like Sanyo or Samsung. That will not only give you more kWh's but also be cheaper than getting a premade stack. With the difference in $$ you could even get one panasonic solar panel to charge the thing, extending its use even further.
Post Reply Post Reply
#3
RE: Comparing old battery to new - Something I forgot to consider
I’m not sure how heavy the batteries are, but I’d rather carry more batteries rather than dropping pressure settings and risking reducing therapy. But that’s just me.
Dave

OSCAR
Standard OSCAR Chart Order
Mask Primer
Dealing With A DME
Soft Cervical Collar Wiki
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply
#4
RE: Comparing old battery to new - Something I forgot to consider
Check AH of whatever battery you are using. Fully charge it. Reduce the AH rating by a third. Compare to the current draw on your machine (Resmed publishes that data). That's what Resmed does in their Battery Guide. You will probably be safe with that unless the battery is in poor condition/has not been maintained and won't hold much charge...
There.  I said it.

OMMOHY
Contrarian in Residence  
Post Reply Post Reply






Donate to Apnea Board  


Possibly Related Threads...
Thread Author Replies Views Last Post
  How long should I get? [Battery use] Mike97 7 208 11-24-2020, 02:37 AM
Last Post: mesenteria
  Backup Battery Recommendation for High Pressure and Humidity Johnnyde94 20 378 11-02-2020, 10:51 PM
Last Post: SarcasticDave94
  Van Life Cpap to Van Battery ilovehotshot 3 163 10-09-2020, 12:22 PM
Last Post: mrmagloo
  My battery backup setup GeoffD 303 60,924 10-02-2020, 12:19 AM
Last Post: vk3hjq
  Talentcell battery and Airsense 10? wordsandsigns 2 189 09-07-2020, 04:09 AM
Last Post: wordsandsigns
  Battery Power Pack - would this work for camping? Hydrangea 14 2,200 09-03-2020, 01:44 PM
Last Post: wordsandsigns
  How Many Nights of Travel with the PILOT-24 LITE battery with Resmed Air Mini dreamstream 1 219 08-28-2020, 09:26 AM
Last Post: Sleeprider


New Posts   Today's Posts






About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.