Battery Replacement Castle Hill

Battery health in settings is a guide, not a verdict. We check the cycle count and actual capacity, because a battery can read 80% healthy and still sag in voltage under load, which is why a phone dies at 40%. We replace when capacity is well below original or the cell is unstable.

Lithium-ion cells degrade unevenly. A worn cell can show a healthy percentage but sag in voltage the moment the phone draws current, such as when you open the camera or use 5G in the cold. The phone's fuel gauge misreads the drop and shuts down to protect itself. A new cell fixes the voltage sag.

We cycle and calibrate the new battery so the percentage readout tracks the real charge. For MacBooks we reset the system management controller so the laptop recognises the new cell and charges it correctly.