Why my watch battery drains very fast?

Amazfit Bip Lite can stay up to 4 Months basic use/ 45 days regular use.

4 month battery life is tested with a basic use: time display, exercise monitoring and sleep monitoring.

45 days battery life is tested with the following use: a 30-minute workout each week, receive 100 notifications each day, and screen brightness level is set at 10%. Actual battery life may vary owing to differences in individual usage. 

If your watch battery is draining fast, please change the watch to the default dial and then make the following test:

Fully charge the Bip Lite to 100%, remove it from charger, turn off Bluetooth on your phone and make it untouched for 24 hours. If power consumption is equal or less than 3% in 24 hours, it means battery is working normally. If it is greater than 3%, it means battery is draining very fast.