Will fast charging damage the battery? Avoid misunderstandings and learn to charge scientifically →

In today's fast-paced urban life, many people have anxiety about the battery life of their mobile phones. Making phone calls, chatting on WeChat, watching videos, playing mobile games... mobile phones seem to have become peripheral organs of our bodies, which makes people particularly concerned about the battery life of their mobile phones. Fast charging came into being. So what exactly is the fast charging technology of mobile phones? Will fast charging damage the mobile phone? How to charge the mobile phone to make it run healthier?

01 Fast charging is an inevitable choice

The battery of a mobile phone is equivalent to the fuel tank of a car. If we want to make the car run longer, we can easily think of improving it from two angles: "expanding the volume of the fuel tank" and "improving the efficiency of gasoline use". Unfortunately, for current mobile phones, both of these approaches are already very difficult.

Due to the limited internal space of the mobile phone, the battery capacity is limited by the occupancy of components such as chips and cameras. Various mobile phone manufacturers have also been constantly trying to make more space for the battery and increase the battery capacity. For example, in the era of feature phones, 800mAh batteries can be called "large capacity", and the battery capacity of the first generation iPhone in 2007 was 1400mAh. By the time the HUAWEI Mate 70 was released in 2024, its battery capacity had reached 5300mAh.

As smartphones become more powerful, their battery capacity keeps increasing, but they consume power faster than before. So, can we improve the quality of "gasoline" and increase the energy density of batteries? In fact, scientists have been working hard, but due to various factors, the principles and application materials of mobile phone batteries have not changed fundamentally. Today, most mobile phone batteries are still lithium batteries that have been used in the era of feature phones, and the energy density of batteries cannot be significantly improved in a short period of time.

Of course, there is another way, which is to replace the mobile phone battery. However, for the sake of safety and sustainability, mobile phone manufacturers have already given up this path. The non-removable battery means that the mobile phone can only be charged through a data cable, which also makes the "universal charger" a mobile phone accessory out of the stage of history.

If you want to make your car run longer, there is only one way left: reduce the refueling time and increase the refueling speed. For the same reason, mobile phone fast charging technology came into being.

Image source: Pixabay

02 How to charge faster?

If you want to increase the charging speed when the battery capacity is fixed, you need to increase the charging power to shorten the charging time. Power P = voltage U × current I, so if you want to charge quickly, you either need to increase the voltage or the current. The fast charging technologies currently on the market seem to be varied, but in essence they all revolve around these two ideas.

Increasing the voltage is the solution chosen by most manufacturers. Its advantages are that there is no need to significantly change the traditional data line and battery structure, the cost is low, and the charger compatibility is good. However, this solution requires the 220V civilian voltage to be converted multiple times (such as first reducing it to 20V, and then adjusting it to the 4.2V required by the battery), which will cause large energy loss and heating problems in the process. In recent years, some manufacturers have tried to directly realize the conversion from high voltage to low voltage by integrating dedicated chips, but due to technical complexity and cost, it has not yet been widely popularized.

Another solution is low voltage and high current, a typical example is OPPO's VOOC flash charging. This method significantly increases the charging speed by increasing the current, while reducing energy loss and heat. But the disadvantages are also obvious: large currents require thicker wire cores and better materials to support them, which are difficult to carry with ordinary data cables. Special cables must be used to achieve fast charging effects.

03 Does fast charging depend on the data cable or the charging head?

It is worth noting that no matter which fast charging solution is adopted, its actual effect is highly dependent on hardware. To achieve fast charging, a data cable, a charging head, and a mobile phone that supports fast charging are all indispensable.

The current carrying capacity of the data cable directly affects the fast charging effect. Traditional USB 2.0 data cables can usually only carry a maximum current of 2A, while fast charging often requires a higher current (such as 3A or 6A). Therefore, data cables that support fast charging usually use thicker cables and better materials to ensure the stability and safety of high current transmission. For example, USB-C data cables can usually carry a current of 3A or 6A, which is suitable for most fast charging needs.

The output power of the charger must match the fast charging protocol of the mobile phone. Each charger will be marked with its output power (such as 5V/2A, 11V/6A, etc.), and users can choose the appropriate charger according to the fast charging protocol supported by the mobile phone. If you use a low-power charger (such as 5V/1A) to charge a mobile phone that supports high-power fast charging (9V/1.67A), the charger may be overloaded, causing heating or even damage.

Different mobile phone manufacturers have different fast charging protocols (fast charging technologies), such as Huawei's SuperCharge, OPPO's VOOC, etc. These protocols are not completely compatible with each other, so when using non-original charging equipment, the fast charging function may not be achieved. This is also the reason why mobile phone manufacturers emphasize the use of original charging kits. When we buy third-party charging equipment, we must pay attention to whether it is compatible with the fast charging protocol of our mobile phone.

In addition, many data cables and power banks use a one-line multi-pin design. As long as you choose a well-known brand or a product with guaranteed quality, it usually will not cause damage to the mobile phone battery. However, the fast charging protocols of different brands are not interoperable, and such devices may not guarantee fast charging for every mobile phone.

Image source: Pixabay

Not only that, fast charging of mobile phones is also a dynamic process. Many people may have similar experiences: when the battery level of the mobile phone is low, the charging speed is indeed fast at the beginning, but after charging to a certain level, the speed will obviously slow down, and the effect of "fast charging" cannot be felt.

This is actually normal, because when the phone's battery is low, the phone will automatically drive the charger to replenish the power, but this will also generate a lot of heat and loss. When the power reaches 60%-80%, the phone will automatically reduce the charging current, just like when a car is almost full of gas, it will become a trickle. This can reduce heat and protect the hardware inside the phone.

04 What is the scientific way to charge?

The correct charging method can not only extend the battery life, but also improve the overall performance of the phone. With the improvement of mobile phone charging technology, many charging habits or sayings that were popular in the past are no longer applicable today.

For example, a common misconception is that when charging a new phone for the first few times, even if it shows that it is fully charged, it should be charged for a while longer in order to "activate" the battery capacity. This is not true for today's lithium batteries. Because lithium batteries do not have a memory effect, and the phone has been pre-activated before leaving the factory, so we only need to fully charge it to use it.

For example, there is another misunderstanding. Many people think that as long as the mobile phone is plugged in and out of the charging head once, it is considered a charge and discharge cycle. In fact, a charge and discharge process refers to the process of using up the battery power and then recharging it.

So, how can we charge our mobile phones scientifically?

1. Avoid over-discharging and over-charging the battery

Lithium batteries are very sensitive to over-discharge, and frequently draining the battery to 0% may damage the battery. It is recommended to charge the battery when the battery level is below 20%, and keep the battery level between 20%-80%, which is most beneficial to the health of the battery.

Although smartphones usually have overcharge protection, leaving them plugged in for a long time may still accelerate battery aging. It is best to unplug the charger as soon as the battery is fully charged, especially not to charge overnight.

2. Avoid charging in high temperature environments

High temperature will accelerate the aging of the mobile phone battery, so it is recommended to charge in a well-ventilated environment and do not place the phone in places with excessively high temperatures such as heating pads or direct sunlight.

3. Try to use the original mobile phone charger

Since the fast charging protocols of various mobile phone manufacturers are not consistent, non-original chargers cannot ensure charging stability and fast charging effect. Inferior chargers may not only damage the battery, but may even cause safety hazards.

4. Do not use the device while charging

When your phone is charging, watching videos or playing games, the hardware inside the phone will be running at high load, which will cause the temperature of the phone to rise rapidly. In the long run, it will accelerate battery aging and shorten battery life.

Just like the phone itself, the phone battery also has a lifespan. Even if you are very particular about the maintenance of your phone, battery aging is inevitable. Generally speaking, the cycle life of a mobile phone battery is 500 to 1,000 times. When the phone battery begins to age and the capacity decreases significantly, you can consider finding a professional mobile phone repair agency to replace the battery.

Through scientific charging and rational use, the life of mobile phone batteries can be effectively extended. This may be the best way to care for mobile phones, a tool that serves mankind.

Source: Chongqing Science and Technology Museum

Author: Can I dig potatoes? DIY enthusiast, science popularizer

Audit expert: Li Chunli

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