The battery percentage on the Dashboard page shows the real-time power the device has. When the cam is off or the system is offline, no battery info will show on the Dashboard.
While the battery level in Power Management has a different meaning, this module will refresh once per day and upload the battery level at UTC 0:00. But when the cam is off or the system is offline, it shows the battery level recorded last time.
Thus, the data info may differ in these 2 modules.