Phone battery lifespan cut by overnight charging and heat, experts say

Lithium‑ion phone batteries lose capacity over time, but the rate of degradation speeds up when they are kept at a full charge for long periods, especially overnight. High voltage and heat generated while the device is charging – for example when running games or streaming video – further accelerate chemical wear.

Manufacturers offer software safeguards: Apple’s Optimized Battery Charging pauses charging around 80 % until just before the user typically disconnects, while Samsung’s Battery Protect limits charge to about 85 %. Similar features appear on many Android devices. Experts recommend keeping phones in moderate temperatures (0‑35 °C), removing cases while charging, and avoiding intensive use or exposure to direct sunlight during charging to prolong battery health.