CompTIA A+ Core 1 (220-1201)Hardware and Network TroubleshootingMedium
A user reports that their mobile phone's battery percentage drops suddenly from 30% to 5% and then shuts down, even though it was recently charged. This happens intermittently and without warning. Which of the following is the MOST likely cause?
- AA software bug in the operating system's battery management
- BA physically swollen battery indicating internal damage
- CBattery calibration issue or degraded battery cells
- DExcessive background app usage
Show answer & explanationAnswer & explanation
Correct answer: C. Battery calibration issue or degraded battery cells
Sudden, drastic drops in battery percentage, especially from a moderate level, are classic symptoms of a battery that has degraded internal cells or is experiencing a calibration issue, where the phone's software misreads the remaining charge.
Why the other options are wrong
- A. While possible, a software bug would likely be more consistent and widespread, affecting many devices, not just one intermittently.
- B. A physically swollen battery is a serious issue that indicates internal damage, but it usually manifests with physical signs (bulging) and often leads to complete failure or constant rapid drain, not sudden percentage drops from a moderate level.
- D. Excessive background app usage would cause a consistent, fast drain, but not sudden, large percentage jumps or shutdowns from a moderate reported level.
Mobile Battery Sudden Drop
Sudden, significant drops in a mobile device's reported battery percentage, especially from a moderate charge, usually indicate degraded battery cells or a miscalibrated battery management system.
- Battery reports incorrect charge
- Cells can't hold consistent voltage
- Often requires battery replacement or recalibration
Memory trick: Degraded Cells Cause Crazy Counts.