Hi Neighbors,
I’ve seen so many posts here about people having strange problems with inconsistent charging, that I’d like to offer this suggestion:
bobbetts , who posted on Feb. 6, 2020, reported that he had found that putting a small washer under each of the two screwheads which fasten the house wires bringing AC to the doorbell for charging, solved his problem. I tried it too, since I had neither charging nor ringing of my inside mechanical chime, and found that miraculously it worked. After I had wasted so much time trying other things. It may be the cause of your inconsistent charging also. I encourage you to try this simple “fix”.