This question is about the actual product life of the battery, not the time it holds a charge... One of my Lithium-Ion batteries for my Ring Doorbell 2 no longer holds a charge. The product date is February 2018. (And yes, I checked my WiFi connection.) When plugged into the USB cable, it indicates that it is fully charged. However, when installed into the doorbell, it lasts less than a day and returns an out of charge notice. My 2020 dated battery works perfectly. What is the product life expectancy of the lithium-ion battery? Also, could it be a problem with the device itself? Possibly, the internal connections are loose/shorted out and it returns the out of charge message because the power is not flowing correctly? I removed it and examined the battery chamber, it is clean. Thanx!