Mine is a D6.
There are apps and settings that cause the inaccurate reading, so check everything thoroughly to make sure there isn’t anything that might interfere with the battery reading, or any alternative apps you may have installed to show the battery life.
Sometimes a custom Launcher downloaded from the Play store can have sensitive permissions that override the system, which is one of the problems that many have had with the watch. I’m not saying that there’s anything wrong with the watch, it’s just the software we put on it cause problems at times. The same goes for our smartphones, in fact it’s happened to my phone a couple of times, and I simply uninstalled certain apps that I had on it, and the battery life was significantly back to normal. Be sure to check all the wireless/connect settings, including bluetooth, wifi, and gps.
above-mentioned is found from xda.(Great forum)
I can’t find the link.
Hope this will help.