Just FWIW, you can't judge battery life on an occasional dip in the percentage. The battery meter isn't perfect. You'll find tons of people finding that the percentage sits at 100% for an hour and then drops quickly after that. The battery didn't simply not drain for an hour and then start draining quickly, it's the software trying to approximate. Go from full charge to near dead and see what happens.
So punish me for weakness, blame me for everything.
I don't like suffering, I like the sympathy it brings.