If you're on a Mac, try Coconut Battery to check the battery health. Mine was showing 30% of original capacity, which explained why it kept draining quickly. Resetting (recalibrating?) it by letting it drain completely and letting it charge got it back up to 80%. I don't know why it had gotten into a bad state :(
> I don't know why it had gotten into a bad state :(
just ordinary use makes them that way. Calibrating is necessary for all lithium batteries, but normally you charge when you think its time and don't wait for the battery to get empty first
