I’m thankful I found this thread. My Ring 2 worked flawlessly all Winter long, but yesterday I got a low battery notification. The app said it was hard-wired, but obviously it wasn’t charging. I pulled it all apart, charged the battery to 100% via USB, did a complete reset, and reinstalled using the washers. I also setup everything to use the maximum amount of battery, so if it starts going down, I’ll notice it quickly. If this doesn’t work now, I’ll call Support and complain.
I bought into the entire Ring ecosystem. Security cameras (indoor and outdoor) and the alarm system. I haven’t installed the alarm system or external cameras yet. Too late to return anything. 
Hopefully the washers will do the trick. If not, hopefully I can get a new device out of this.