Charging a smartphone overnight is common, but where you place it can make a serious difference. A phone hidden beneath a pillow, blanket, or mattress cannot release heat properly. As the temperature rises, the battery, cable, and charger may become dangerously hot.

Modern phones include systems designed to manage charging, so leaving a healthy device connected overnight is usually not the main problem. The greater danger comes from trapped heat, damaged batteries, worn cables, cheap chargers, or devices that have already been dropped or crushed.

Lithium-ion batteries can fail when they become damaged or severely overheated. In rare cases, the phone may release smoke, catch fire, or rupture suddenly. Because bedding burns easily, a small battery failure beneath a sleeping person can quickly become a much more serious emergency.

Never ignore warning signs such as unusual heat, swelling, strange smells, leaking, crackling sounds, or changes in the phone’s shape. Stop charging the device immediately, move away from it, and have it inspected by a qualified technician.

Charge your phone on a hard, flat, uncovered surface with plenty of airflow. Keep it away from pillows, blankets, clothing, and other flammable materials. A simple change in where you leave your phone at night could protect you, your family, and your home.