With Qualcomm® Quick Charge™
3.0, your phone's battery can receive a 50% charge in 30 minutes or less—may vary depending on charging equipment and power source. After surpassing 50% charge, the charging speed slows down slightly to prevent over-stressing the battery.
Heat accumulates and power dissipates if your phone is charged while it's in use. To avoid this, quick charging starts after the screen is turned off. It is also normal that charging may speed down automatically to avoid possible damage to your phone when the phone starts heating up or the surrounding temperature rises.