Hello, I would use batteries rather than rechargeable batteries. Depending on the setting, between 8 and 14 days for me. Observe such a birdhouse with a lot of operation. Greetings
With Eneloop or Ladda batteries with 2450 mAh, the camera runs for over 8 weeks in standby mode with a few dozen shutter releases. Even in winter when it's cold. With video recordings or a lot of night shots (IR light), sometimes even less.