For one: I read the thread and the constant battery charge seems to be a problem. Lithium cells hate (overcharge) when they are full and charging is not stopped. Setting the float V to the battery relax V (ca 16 x 3,3V) could solve it ? (so no V difference and so no current is flowing) To be fair, ...
unfortunately the MK does not seem to have the Setting 03... it jumps from 02 to 05... This is no longer the case (certainly in firmware >= 71.92, maybe earlier). While the LCD still does not support setting 3 (even in latest firmware 2.49), Appliance mode can be set in WatchPower or using the PGR0...