I live in an area with rolling power outages, and purchased this as backup power for those occurrences. I tested the device on my DreamStation bipap. I disconnected the humidifier, and attached the hose directly to the bipap machine. Replacing the mask & inserting a paper towel in the hose, 2 (two) lights remain illuminated after 11 (eleven) hours.
Adding to this review, as I began recharging the battery, 1 (one) light remains solid, so after 11 hours of use, I’ll say the remaining charge is 1+.