Ring Video Doorbell 2 shows hardwired, but is not charging.

Hi there. I've had the RVD2 and I absolutely love this thing... except that it doesn't charge on my doorbell wiring. My house had: - Old school doorbell - Old school analog chime - 20v transformer (15VA). What I've done/tried: - Installed Ring (With 100% charged battery) to old doorbell wiring (RVD2 showed hardwired, but battery level slowly dropped over the weeks) - Bypassed old chime with the recommended wire-wound resistor in place (RVD2 same symptoms) - Replaced transformer with the recommended 16V 30VA one. (Same symptoms) - Verified with multimeter 17VAC at the doorbell. (Only a 0.4VAC drop between transformer and doorbell) - Charged battery to 100% again to be sure. (Battery level keeps dropping after that) I'm insure what to try next, so here I am. :) Thanks! --Micah