I just bought a brand new 38mm champagne gold sport model... it came without OS2 preinstalled so I had to install it once I got home. First couple days I had easily ~40% left at bedtime near midnight. Then one day at work, I went to put it back on at 4 pm (we have to store our electronic devices in locked boxes because of security) it was 99% when I put it in there - on airplane mode - at 0800 and at 1600 it would not turn on. I held the button in, and only the time and a red bolt icon... so the watch battery was nearly dead. The entire day it was locked in a locker on airplane mode. Makes no sense... BUt then I realized something weird happened... I had the phone sitting on it's side, and the next day I realized that somehow that new bedside function might be the cause even though it wasn't attached to the charger. I read someone else had turned off bedside mode and the issue has not happened again. I didn't alter my bedside mode... but I have been making sure it is sitting flat when in the locker and it has not happened again since. I am back to 40% or so by bedtime, and I never did the re-pairing thing. So either it is keepign it flat that's working, or the fact that the watch battery literally died, the watch rebooted and maybe it was the reboot itself that fixed it. But I thought I should mention there may be a glitch with the bedside mode in that it sometimes activates even without the charger attached. And that mode is new with OS2 is it not?