Stick up cam with Solar Panel

So I've installed all and had a fully charged battery in it.. during the day it connects to the solar panel according to the app, but once the sun goes down.. my battery life goes down immediately and by morning its dead.. so each day I've been having to replace it with another one. Why is this happening.. what is wrong with this thing.. I mean i have the doorbell and that one last a very long time. Not the 6 months it says they will last though.. how can i make them last. and still get my alerts? How can this issue be fixed.. as i am tired of going up there every morning to replace the battery and also, what kind of security do i really have at night being its dying during the night. What is it.