Hardwiring can only charge the doorbell at a fixed rate. If the doorbell is triggered too often, it consumes the battery quickly, and the power supply from hardwiring may not be enough to sustain the usage.
In this case, we suggest you make sure the power supply is between 8 - 24V, and also lower the motion sensitivity in motion settings and select Human Only or Smart Alert. It will reduce the number of events captured and improve battery life, so the hardwires can start charging the battery back to a battery level higher than 80%.
In addition, the signal between the chime and the doorbell also impacts the battery. Generally, when the signal needs to be maintained within a range of -30 to -50 to be considered as a good signal reception. Otherwise, the doorbell would constantly search for the chime in order to get data transferred, which consumes its battery as well.
In this case, please kindly check the Network Diagnosis feature in the WUUK app and move the chime and doorbell in order to find locations for both to keep the signal indicator index within -30 to -50 range.
Please also read: (Device's settings>Network Diagnosis)