In fast charging you increase the voltage level of the current, while the amperage remains the same. It is not dangerous to the health of the smartphone
While waiting for the lithium-ion battery industry to be retired by new technologies, for smartphone owners the most convenient solution are fast charging systems that allow you to have 50% battery life or less with just a few minutes of charging.
Most of us when we bought a smartphone equipped with fast charging will have wondered how this feature of the phone works. It's simple, when you connect a smartphone to the charger, the current from the electrical system is "filtered" by the internal circuits of the power supply. This is to prevent too strong a current from damaging the internal components of the smartphone. Usually phones have a 'threshold' beyond which there is a risk of short-circuiting the device. The charger therefore has a function to control the incoming energy.
The quick charge maximizes the charging efficiency by increasing the level of power (or wattage) that can be absorbed by the battery. Decreasing charging times. In fast-charging systems, the current voltage is increased while the amperage remains almost unchanged. Obviously the devices have chips to manage these current flows much more powerful than in the past.
Is fast charging dangerous?
Contrary to what you may think the fast charging system is not dangerous. In fact, the opposite is true. Work on managing incoming current flows on phones has led to higher safety standards that manufacturers must follow. So much so that at the moment almost all brands that make smartphones have implemented quick charge on their models.
A Varied Technology
It's difficult to classify the various technologies adopted for quick charging, each manufacturer is currently developing its own customized solution. The technology known as Quick Charge is currently the most appreciated and used. It is made by Qualcomm, the world's largest manufacturer of chipsets and components for mobile devices. This solution allows for 5 hours of battery life on top-of-the-line phones with just 5 minutes of charging. OnePlus, the Chinese smartphone company, has made its own system which is known as DashCharge. While recently, the Oppo company stated that they have made a fast charging that allows a full charge in just 15 minutes.