Did a full run down of the battery with the watch recording voltage. This is super easy to do because the BC127 does all of the battery management. Most of this just involved writing the library routines to poll the bluetooth and I just now got the recording to a file and graphing part working good. Next up is battery stats and building a lookup table to turn the voltage curve into a more linear 0 - 100% capacity kind of number.

EDIT: Put in some min/max voltage numbers and you can see the whole charge cycle.