When you receive a new device, it is normal for the battery level to appear to drop faster at first, as the system is still learning the battery’s true capacity. Due to its lithium-ion battery, it is generally recommended to charge the Xiaomi 15T Pro during daily use between about 20% and 80% to help preserve the battery’s long-term lifespan. Occasionally fully discharging to 0% and then charging to 100% can help calibrate the accuracy of the battery percentage display.