Tired of changing CR2450 battery idea

As I was very tired of changing out my garage door open/close sensor Cr2450 battery a lot I converted the sensor to accept a single cell rechargable lipo RC battery. Seeing I’m heavy into RC planes and helicopters and had a bunch of these cells laying around with chargers I made this. See pic. Now once it goes low I just pop it off and charge it 15 min.
Now that I know it works I’ll get a cleaner larger mah battery and fabricate a better mounting system for battery.

How do you know when battery level gets low?

It’s like any other battery. I just soldered the battery connector tails to board.