In modern life, smartphones have become an indispensable item for billions of people around the world. Not only a means of communication, smartphones also act as miniature computers that help us entertain, study and work anytime, anywhere. Therefore, the need to use smartphones continuously makes battery life a top concern. When the battery is low, most users tend to plug in the charger and continue using the device, regardless of whether it is for texting, watching movies, surfing social networks or playing games. This has become a very common habit.

However, the question is: Is it really safe to use a smartphone while charging? Are concerns about explosions, battery failure or reduced performance true? Many people still do not really understand the impact of this seemingly harmless action. In particular, with the popularity of fast charging technology today, the potential risks become more noticeable when the voltage and heat during charging can be much higher than before. To find the correct answer, we need to deeply analyze factors related to the battery, temperature, operating mechanism of the smartphone and the potential risks when charging and using at the same time. This article will help you understand the nature of the problem and give the right advice to use your smartphone more safely and durably.

1. The danger of using a smartphone while charging the battery

When a smartphone is in operation, especially with heavy tasks, many hardware components will have to work at high intensity. The central processing unit (CPU) and graphics processing unit (GPU) are the two components that consume the most energy, and are also the places that generate the most heat. Under normal operating conditions, manufacturers have designed a heat dissipation mechanism to keep the device at a safe level. However, when charging and using at the same time, the amount of heat generated increases significantly, because the charging process also generates heat from the battery and circuit.

According to research and practical testing, when handling heavy tasks such as playing 3D games, recording 4K resolution videos or watching online videos continuously, the CPU temperature can reach 60–70°C. In the case of charging and using at the same time, this temperature can increase even higher, even reaching 75°C or more depending on environmental conditions and charger type. High temperatures are not only uncomfortable to hold, but also lead to more serious consequences for components and batteries.

A built-in protection mechanism in most smartphones is to automatically reduce the CPU clock speed, reduce screen brightness or reduce the scan frequency to limit heat. This is the reason why you may see the device jerk, lag, and significantly reduce performance when charging and playing games at the same time. However, if this situation persists, the performance reduction is only a temporary measure, the long-term consequence is the rapid degradation of the battery and electronic components.

Lithium-ion batteries, the type commonly found in smartphones, are sensitive to high temperatures. When batteries are exposed to heat frequently, chemical reactions inside them occur more quickly, causing unwanted structures to form that reduce their ability to store charge. In other words, the battery will wear out and lose capacity sooner than expected. In more severe cases, excessive heat can cause thermal runaway, which can lead to fire or explosion. Although this is a rare case, it has happened in real life and the consequences can be extremely dangerous.

In addition, when charging and using at the same time, the cable and charging port are also subjected to more mechanical pressure. Users often hold the device in many directions while playing games or surfing the web, accidentally creating force on the connection port. In the long run, this can loosen the USB port or damage the connection pins on the motherboard, leading to unstable charging or no charging. Repairing the charging port or replacing the motherboard is not only expensive but also has the potential to affect other components.

Another less-mentioned risk is an unstable power source or a poor quality charger. If the charger does not have a protection circuit, when charging and using at the same time, the fluctuating current can cause short circuits and overvoltage. Some cases of electric shock have been recorded, although the rate is very low, most of them are related to the use of unknown chargers.

2. So should you use your smartphone while charging?

The question “should you use your phone while it’s charging?” gets asked a lot, but there’s no simple “yes” or “no” answer. It really comes down to frequency, usage, and the condition of the device.

If you only occasionally answer an urgent call, reply to an urgent message, or quickly check notifications while charging, this is unlikely to cause major harm. Smartphone manufacturers today equip many safety protection circuits such as: controlling the current into the battery, limiting the temperature, and automatically stopping charging when the battery is full. This helps limit the risk when users have to operate for a short time.

However, problems arise when the habit of charging while using becomes a daily activity, especially with heavy tasks such as: playing high-graphics games, watching online movies for hours, recording high-resolution videos or running multitasking continuously. At this time, the phone has to charge and discharge energy at the same time, causing the battery to operate at a higher intensity than designed. The result is:

Fast battery degradation: lithium-ion battery cells degrade faster due to temperature and unstable current.

Charging port and power circuit are vulnerable: constant fluctuation in current and high temperature can reduce component life.

Performance is significantly reduced: the device is prone to overheating, throttling (reducing CPU/GPU clock speed) to cool down, causing lag.

In fact, many people have to replace the battery or even change to a new phone after only 1-2 years because of the habit of charging while using. This causes unnecessary costs.

So the optimal advice is:

• Let your phone rest while charging and use it again when the battery is full or at least 80%.
• If you really have to use it, limit the time and type of tasks, avoid playing games or watching videos for long periods of time.
• Always ensure a cool charging environment and use a genuine charger to avoid voltage risks.

3. How to minimize the risk of having to use your smartphone while charging

Changing habits is not easy, especially for those who work online continuously or have to handle urgent work over the phone. In this situation, the following methods can be applied to minimize risks:

Limit high-heat tasks:
Avoid playing 3D games, recording 4K videos, live streaming, or making long-term video calls. These activities cause the CPU, GPU, and battery to heat up quickly, and combined with the heat from charging, the device will heat up many times more.

Use a quality and standard charger:
Always use genuine chargers and cables or those that are certified for safety (MFi, UL…). Cheap, floating chargers often do not have protection circuits, leading to the risk of overvoltage, short circuit and explosion. There have been many recorded cases of explosions due to poor quality chargers.

Keep your phone cool:
Avoid leaving your charger under a pillow, on a blanket, or in a room that’s too hot. Soft surfaces retain heat for a long time and also block the device’s ventilation slots. If possible, remove your phone case (especially a thick one) while charging to help it dissipate heat better.

Watch for unusual signs:
If your phone is overheating, has a burning smell, the battery is bulging, or is charging too slowly, immediately disconnect the charger and take it to a service center. These are serious warning signs. Do not attempt to continue using it as the risk of fire or explosion can occur at any time.

Smarter charging:

• If possible, use a longer charging cable so that the device can be placed in a cool place without getting in the way when needed for light use.
• Intermittent charging: for example, when the battery is 30-40%, charge it to 70-80% then unplug it to use, avoid continuously charging and discharging.
• Some devices support smart fast charging and limit charging to 80-90% at night, take advantage of this to reduce stress on the battery.

Applying these measures not only protects the life of the battery and components, but also helps reduce the risk of fire and explosion, ensuring safety for you and your family.

4. Conclusion

Using your smartphone while charging isn't always immediately dangerous. But if you make it a regular habit, you're shortening your battery life and increasing your risk of hardware failure. In particular, with today's fast charging technologies, the current and heat are much higher than before, so you need to be even more careful. Remember that smartphones are sophisticated electronic devices and lithium-ion batteries are not endless energy. Proper care will help you use your device more durably, avoiding many unnecessary risks. Occasional use while charging is acceptable, but limit heavy tasks and prioritize letting the device rest while charging. If you do it correctly, you'll both ensure your own safety and extend the life of your device.