Spotlight Camera Plus power issues

I have a Spotlight Camera Plus which is hard-wired and has 1 battery pack for backup power. Worked great for 10 months and then suddenly shut off. Checked the outlet and it’s working fine, checked the wire from the outlet to the camera and it’s in good condition. Verified the wire is securely inserted into the camera. Took the camera down and fiddled with the battery pack and the camera started working again, but the battery pack is totally drained. Shouldn’t the battery pack be trickle charged and never need to be manually charged? What would cause the camera to shut down (lose power)?