Charging in direct sunlight, under a pillow, or inside a sealed bag traps heat around the battery and charger.
Modern chargers include multiple protection circuits — over-voltage, over-current, short-circuit, and thermal cutoffs — but these protections are only as reliable as the manufacturing quality behind them, which is why certification matters more than price.
| Certification | What It Confirms |
|---|---|
| UL certification | Underwriters Laboratories testing for electrical safety, common on North American electronics. |
| USB-IF certification | Confirms a USB-C cable or charger actually meets the power and data specifications it claims. |
| CE marking | Indicates a product meets European Union health, safety, and environmental requirements. |
| FCC ID | Confirms a device has been tested for electromagnetic compatibility in the United States. |
What to do
For overheating, the fix is usually simple: charge on a hard, ventilated surface, replace visibly worn cables, and buy from brands that publish certification numbers rather than just a certification logo.