Ring doorbell2 with solar panel

Hey all I have a ring doorbell2 I believe it’s a second gen . I moved and went from a wired door to a non wired door . Instead of charging all the time I decided to purchase a solar panel for the charging of the doorbell2. Doesn’t seem like it’s charging because it’s still dieing . How can I confirm it’s the solar charger , battery pack not holding a charge or if its not compatible with the panel?