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 the phone was working normally moments before. This behavior is consistent and repeatable. Which of the following is the MOST likely cause?
- AA failing battery that cannot accurately report its charge.
- BOperating system power management bug.
- CExcessive background app activity.
- DPoor cellular signal strength.
Show answer & explanationAnswer & explanation
Correct answer: A. A failing battery that cannot accurately report its charge.
A sudden, significant drop in battery percentage, especially from a moderate level to very low, is a classic symptom of a failing or degraded lithium-ion battery. The battery's internal resistance increases, causing its voltage to drop rapidly under load, and its ability to report accurate charge levels degrades.
Why the other options are wrong
- B. An OS bug might cause incorrect reporting, but less likely to cause a consistent and repeatable 'cliff' drop with immediate shutdown.
- C. Excessive background activity would cause rapid, but usually linear, battery drain, not a sudden percentage jump.
- D. Poor cellular signal drains battery faster, but typically as a more gradual process, not a sudden percentage drop followed by shutdown.
Mobile Battery Degradation
The natural decline in a mobile device's battery capacity and ability to hold a charge over time, often leading to inaccurate charge reporting and sudden shutdowns.
- Lithium-ion batteries degrade with age and charge cycles.
- Symptoms include rapid, non-linear discharge and sudden shutdowns.
- Often results in the battery management system misreporting remaining charge.
Memory trick: A failing battery often 'lies' about its power level, then dies.