...or not enough of it, at least. Despite having fully charged the portable battery, it proved unable able to keep my CPAP running all night long. Based on when I woke up to find it the machine no longer blowing air, it must have lasted maybe five hours or so. That's unfortunate. I would have bought a larger battery, but all of the larger ones that were on offer didn't have 12VDC outputs -- only vehicle battery clamps and USB charging outlets. There's not a lot I can do about this other than to use the unit anyway and accept that getting five hours of relatively restful sleep is an improvement over none at all. And the unit is potentially useful as an emergency jump-starter, anyway.