Why is the charging process of a fast charging charger fast and slow?

Many friends who use fast charging report that when using fast charging, charging is fast before 80%, slow charging after 80%, and slower after 90%. Was it cheated by the fast charge?

In fact, the realization of iPhone fast charging requires the combination of the phone itself, the charging head and the data cable.

Apple started to support fast charging from iPhone 8. By increasing the current into the lithium battery, the battery activity becomes higher and the current can be obtained faster. Due to the high current, the heating effect is aggravated and the battery generates high temperature, which will cause irreversible damage to the battery.

Therefore, Apple has developed a complete set of circuits, batteries, interfaces, data cables, as well as supporting fast charging adapters and intelligent battery management systems, so that the iPhone can adjust itself according to different charging conditions to protect the battery.

In addition, the intelligent charging process of the iPhone is divided into three stages:

The first stage belongs to the pre-charge stage. A significant feature of the iPhone when using PD protocol for fast charging is that it will be pre-charged at 5V/2.4A when it is turned off, limiting the charging function and ensuring battery safety.

In the second stage, constant high-current charging is used. At this time, the charging power will reach its peak and quickly reach 80% of the electricity.

In the third stage, switch to a slower trickle charge mode to avoid excessively high fast charge temperature from affecting battery life, so that the battery power can reach a saturated state and extend the battery life.

Apple did this not only to extend the life of the battery, but also for charging safety considerations.

The qualified charger itself also has multiple protections. For example, Green Union 20W fast charge provides six safety protections: overcharge protection, over current protection, over power protection, short circuit protection, over temperature protection, and lightning protection. Filtering is dangerous.

Green Union 20W charging head has also passed the domestic CCC&CQC double safety certification. CQC certification is the latest standard promoted by the switching power supply industry. Its certification process is more stringent than 3C certification. The addition of more than 61 stringent inspection standards means that reliability and stability are more guaranteed.

It is worth noting that when purchasing a fast-charging charger, you should try to choose products that have been certified by MFi, which can be upgraded with the iOS system simultaneously to avoid pop-up warnings. Inferior chargers will accelerate the wear and tear of the iPhone’s battery, and may even have a risk of explosion.