Light Weight and extremely easy to use
Background:<br />I am a Scout leader in Washington state and have been on Cpap therapy for nearly 20 years. I love the outdoors and for many years this meant that I would have to suffer through many nights without my Cpap to be able to take scouts out into the wilderness.  Several years ago while searching for new ways to be able to bring my Cpap with me I found the K5 by Max Oak.  This was a game-changer at 4.4Lbs I was able to take this with me and use my Resmed Air-Mini to have a restful night sleep on this battery I would get 5 to 6 nights and while this is great for longer trips most of our outings are only two-three nights and carrying a 4.5lb battery wasn't really needed.  My normal settings are in the 12-13 cmH2O and with the added altitude the Air-Mini has to work a little harder to keep the pressure up.  This means that any battery that I might use would not have a run time as normally listed.<br /><br />Personal Experience:<br />In our most recent outing, we were at 3500ft which I know is not super high but it's high enough to notice the difference. We left out Thursday and came back on Sunday. We had ordered the Freedom V2 (For Resmed Air-Mini) earlier in the week and were awaiting its arrival on Thursday to be able to leave for the outing. When it arrived at about 2:45-3:00 PM I took it out of the package and noticed it was at ~70% and needed to be charged.  We had some running around that needed to be done so I pulled the power plug on my AirSense 10 and plugged in the Freedom V2.  It was only on the charger for maybe an hour when we returned and were ready to head out.  If memory serves, it was somewhere in the 90's for percentage when I took it off the wall charger, I grabbed the DC charger for my Air-Mini and plugged it into the car's 12volt system while we drove to the trailhead (Please note that the Air-Mini DC plug is NOT a standard item and must be purchased separately, until this point I had never actually used it, I think it was $80 for the DC plug it will accept 12vdc or 24vdc to provide power to the Air-Mini).  using the DC converter plug it was fully charged in no time.  I was very impressed with how fast the Freedom V2 charged.  I never sleep well the first night but after the first night the Freedom V2 was still at over 60%.  I knew ahead of time that based on the statistics that the manufacturer listed it was VERY unlikely that I would get 3 nights out of the Freedom V2 but I had a plan for that.  We needed to move more food from the car to the campsite over 3 miles apart on Friday so we left one of the K5 batteries in the car in a day pack to be retrieved when we went back for the additional food.  because the Freedom V2 uses an adapter cable from the Air-Mini to charge I was able to use the normal cable from the K5 for my Air-Mini to input the 24VDC into the Freedom V2 and fully charge it.  This worked GREAT and I was able to easily fully charge the Freedom V2 in a matter of only a few hours.  Then on Saturday some of the members of our party left and they took the K5 back to the car and I was able to sleep two full nights at about 7hours the first and 8-9 hours the second and the Freedom V2 had not depleted the charge in fact there was still 8-10% left.<br /><br />Conclusion:<br />At 1.35Lbs and with nearly 100WH of power this little battery packs a punch.  I always see more power drain on the trail than when testing at home (due to being at altitude and many temperature fluctuations) so being able to get two full nights from a battery that is 3lbs lighter than the Max Oak K5 is amazing it will make shorter hikes much more enjoyable.  The price is par for the course.  As these are advertised at "Medical Devices" I think it's really just an excuse to bump the price up an extra $100 but the build quality is nice and the interface is much better than that of some of the other options.  After reading many reviews I settled on trying the Freedom V2 and so far I am glad I did.  I only have 3 nights on the battery right now so I will reserve comments about how well the battery holds a charge over time and whether or not there is any degrade in performance over time.  I intend to do a three-night sleep test here at the house this next week and will post any useable data from that.  At this point, I am extremely happy with the quality and weight of the unit and am looking forward to any updates that Freedom may come out with in the future.<br /><br />Other considerations:<br />To address one of the other reviewer's comments about the internal parasitic drain of the battery. This is normal to some degree with any battery that has electronics hooked to it.  Most times it is very negligible and not noticeable.  If it becomes noticeable I would reach out to the company for a replacement as one of the cells may be damaged. But it is not uncommon for batteries to slowly discharge over time (many weeks or even months in storage) even lead-acid batteries do this (the effect is made more evident when you place a lead-acid battery on concrete).  Please consider discharging to ~50% and recharging any battery before use if it has been in storage.  If the battery won't discharge then hook it to the charger and allow it to awaken the cells as they may have been placed in hibernation/storage by the electronics to prevent damage.<br /><br />Its my pleasure to use this battery and I look forward to many overnights.  If anyone has any good ideas on other ways to charge this battery out in the field please contact me as I am always looking for ways to extend our trips.<br /><br />Nick V.
Rating: 5 stars