1.  Plug the Phone In First or the Charger First?

When charging your phone, should you plug the phone in first or the charger? The correct answer is plug the charger in first. When you charge your phone, the charger converts high voltage into low voltage through a transformer, and then transfers it to the phone.

If you plug the phone into the charger first and then into the socket, there’s a risk that the phone could connect directly to the power supply, causing a sudden voltage surge. However, if you plug the charger into the socket first and then connect it to the phone, this situation almost never occurs, unless the power supply is unstable.

It’s best to plug the charger into the socket first, then connect it to the phone to avoid the risk of electrical shock.

2.  Should You Unplug the Phone or the Charger First After Charging?

The correct answer is unplug the phone first. When you unplug the charger, a reverse current is generated, which can accelerate the aging process of the battery.

Although the principle may seem complicated, you can remember it simply: consider the charger, charging cable, and socket as one unit. When charging, the phone is "attached" to the charger, and when fully charged, the phone is "removed."

3.  Should the Phone Be Charged to 100%?

The phone battery is primarily lithium-based, which operates through a continuous charging and discharging process between the positive and negative electrodes. If the battery is overcharged or discharged too deeply, the structure of these electrodes may be damaged, reducing the battery's capacity and lifespan.

Although many phones have overcharge protection features, you should still develop good charging habits. The best practice is not to wait until the battery is completely drained before charging. Instead, charge it regularly with a lower level of charge, which helps prolong the battery’s lifespan.

4.  The Da.ngers of Incorrectly Charging Your Phone Battery

Most users tend to leave the charger plugged into the socket after each charging session. This not only wastes electricity but also creates a risk of short-circuiting and fires, especially when using third-party chargers or chargers from unreliable sources.

Additionally, leaving the charger plugged in continuously can cause it to heat up, potentially leading to electrical short circuits and fires. Therefore, after charging your phone, you should unplug the charger from the socket to ensure safety for both the device and those around you.

Moreover, during the charging process, smartphones charge through the charger by transferring energy via the charging cable. At this stage, the phone charger functions as a transformer, converting high voltage to low voltage (from 220V down to 5V, 9V, 12V, etc.) and providing the direct current to charge the battery.

Thus, during the entire charging process, plugging the charger into the power supply first is considered the correct step. Only when the transformer steps down the voltage will the phone be charged fully.

5.  Tips for Charging Your Phone Battery:

• Plug the charger into the socket first, then connect it to the phone.

• Unplug the phone from the charger before unplugging the charger from the socket.

• Avoid charging the battery to 100% or letting it fully deplete.

• Do not leave the charger plugged into the socket when not in use.

• Use official chargers that are compatible with your device to ensure safety and prolong battery life.