IPhone 12 can support PD fast charging protocol. Both 20W and 30W fast charging devices sold in official website can charge iPhone 12, and the estimated charging time is within 30 minutes of 1 hour.
At present, there is no research showing that fast charging has an effect on the battery of iPhone. Whether using 5W charger or 20W charger, the battery health will not be different.
The battery health in the iPhone is related to the number of times of charging, which is a complete charging and discharging process. The process that the battery is fully charged from 0% to 100% is called a complete charging and discharging.
Matters needing attention
During fast charging, due to the large current, the thermal effect of current will be intensified, and the heating speed of iPhone will be accelerated. However, in actual use, whether it is ordinary charging or fast charging, it will cause irreversible damage to the battery, but the damage of fast charging will be slightly stronger than that of ordinary charging.
Although the damage is inevitable, it will not appear in a short time, and it will take a year or more to see the decline of the battery. A year later, the battery became not durable, not a quick charge, but an inevitable result.
In short, fast charging does have an impact on the life of the battery, but don't worry too much, because whether the battery is in use or charging, it will cause battery loss, but this loss is very small and completely normal.
However, it should be noted that when buying a fast-charging charger, you should try to choose products with MFI certification. Inferior chargers will definitely accelerate the loss of iPhone batteries.