Bests & Worsts Reviews from Amazon

This 6.35 pound 250 Watt , 64.8 Amp Hour battery is a go when it came to powering my Philips Respironics Auto DreamStation CPAP for 7 nights. On the 8th night the CPAP quit after 3 hours. At that point the Rockpals measured 9.4V DC. Connect directly to one of the four 12 volt connectors. I used the included Rockpals cigarette lighter adapter. If you are a DreamStation user you’ll need this part: 12V DC Power Cord For Philips Respironics DreamStation – yeah it’s expensive; approx. $30, unfortunately a standard inexpensive barrel connector won’t fit; soooo get the correct cable. My settings on the CPAP were: Auto On (Pressure Range: 7-18 cmH2O); Modem Off; Bluetooth Off, No Humidifier Connected, Heated Hose Off. I also had the battery’s toggle switch in the OFF position. That switch engages the battery's 12 volt DC to 120 V AC converter and also illuminate the LEDs that show how much battery is left; running those status LEDs just wastes juice and the four 12 volt connectors are always on regardless of toggle switch position; so switch the toggle ON to check status LEDs and determine how much battery capacity is left and then switch it OFF. Nothing else was connected to the battery; only the PAP. I also unplugged the PAP from the battery during the day. I averaged btwn 7-8 hours a night of sleep and my average 90% pressure was 10 cmH2O. I also took current draw measurements. At standby (machine on but not blowing) it draws 0.16 Amps & 0.09 Amps when the screen goes dark. I measured the following current fluctuations with the machine blowing wide open, meaning no mask was on my face: 4 cmH2O 0.3- 0.45 Amps. 7 cmH2O 0.6-0.8 A. 10 cmH2O 1.02 – 1.25 A. 12 cmH2O 1.3 – 1,5 A. 14 cmH2O 1.4 – 1.7 A. 16 cmH2O 1.9 – 2.1 A. 18 cmH2O 2.1 – 2.5 A. 20 cmH2O 2.6 – 2.9 A. With the mask in place and “normal” breathing I measured between 0.31 – 0.62 A at 7 cmH2O. The machine used less current on the exhale. I also tried the 120 AC side using the DreamStation standard 120 AC to 12 V DC brick that comes with the PAP. On a full battery charge, and 8 hours of sleep, battery capacity dropped to about 50%-60% - 2 battery LEDs OFF, 3 ON. Obviously, this is not an efficient way to run a PAP. In conclusion if you use a PAP similar to the Auto DreamStation that runs on 12 volts, you can assume quite a few nights of off the grid sleep. If you average about 10 cmH2O you should expect about 7 nights as long as you don’t use a humidifier, have the heated hose powered OFF and don’t sleep more than 8 hours a night. Hope this info helps. I’ve never been able to find real world current measurements at different pressure settings for any PAP machines so I decided to take my own. Pleasant Dreams! NOTE: The meter in the photo shows 0.64 AMPS at & 7 cmH2O with the blower running at full blast -- kinda hard to see the decimal point.