How do you know if your doorbell solar panel is working.

I have a ring doorbell 2nd gen with the compatible solar charger. The area the doorbell is in gets direct sun for 4 to 5 hours on a good day. The doorbells charge continually decreases and I understand that the setting can affect the battery life but I'm not sure how to tell if the solar charger is doing anything. Is there any easy way of telling if the charger is working? I also have a battery spotlight cam with solar panel not far from the same area and it will be fully charged in the same period of sunlight (4 to 5 hours) and it also tells you that a solar panel is connected but yet the doorbell doesn't say anything. I would appreciate some help clearing this up if anyone knows.