Many people have heard the saying that "it is better to charge the phone after it shuts down automatically". Some people think that this can "calibrate the battery", while others think that it can extend the battery life. However, this concept actually originated from the early era of nickel-metal hydride batteries and is not applicable to the lithium batteries of modern smartphones. This article will explore the characteristics of lithium batteries in depth, reveal the truth of this misunderstanding, and share scientific charging suggestions.
I. Why is there a saying that "it is better to charge the phone after it shuts down"?
1. Historical background: the memory effect of nickel-metal hydride batteries
In the era of nickel-metal hydride batteries (NiMH), batteries do have a "memory effect". If the battery is charged before it is fully discharged, it will "remember" the shorter usage cycle, resulting in a decrease in capacity. Therefore, users need to regularly discharge the battery completely before charging it to maintain its performance.
2. Revolutionary changes in lithium batteries
Modern smartphones generally use lithium-ion batteries, which work in a completely different way from nickel-metal hydride batteries:
- No memory effect: no need to fully discharge, charging as you use is healthier.
- Fear of deep discharge: low power will damage the electrode structure and shorten the battery life.
- Limited cycle life: The life of lithium batteries is calculated by the "number of charge and discharge cycles". A complete cycle refers to the charge and discharge process from 0% to 100%, but it does not have to be completed in one go.
II. The hazards of automatic shutdown of mobile phones
1. Deep discharge damages the battery
When the battery level of the mobile phone is less than 5% or even shuts down automatically, the battery is in a deep discharge state. At this time, the activity of lithium ions inside the battery is reduced, and the electrode material may be irreversibly damaged, resulting in a permanent decrease in capacity.
2. Increase the risk of "sudden death" of the battery
When the battery level of the lithium battery is extremely low, the voltage will drop below the critical point. If it is in this state for a long time, the battery may enter a "dormant" or even "scrapped" state and cannot be recharged.
3. Affect the user experience
Automatic shutdown may not only lose unsaved data, but also make users fall into "battery anxiety", which is not worth the loss.
III. The correct posture for scientific charging
1. Charge as you use it and avoid extreme power
- Optimal power range: Keep the power level between 20%-80%, which can meet daily use and reduce battery pressure.
- Avoid storing the battery at full charge: Keeping the battery at 100% charge for a long time will increase the chemical stress of the battery and accelerate aging.
2. Turn on the "optimized charging" function
Modern smartphones (such as iPhone and Android flagships) all provide "optimized charging" or "smart charging" functions. By learning the user's charging habits, the device will temporarily delay charging to 100% until the user needs it, thereby reducing the time of full charge.
3. Avoid charging in a high temperature environment
High temperature is the "number one enemy" of lithium batteries. When charging, try to avoid placing the phone in direct sunlight or in a closed environment, and remove the protective case to improve heat dissipation.
4. Calibrate the fuel gauge regularly (optional)
If you find that the power display is inaccurate (such as 20% suddenly jumps to 5%), you can calibrate the power every 3 months:
- Use the phone until it automatically shuts down.
- Charge continuously to 100% without interruption.
- Continue charging for 1-2 hours after turning on the phone to ensure that it is fully charged.
IV. Summary: Say goodbye to misunderstandings and charge scientifically
The saying that "it is better to charge the phone after it automatically shuts down" is outdated. The characteristics of lithium batteries determine that it is more suitable for charging as you use it, avoiding extreme power states. Through reasonable charging habits and smart functions, we can maximize the battery life while enjoying a convenient technological life.
Remember: Batteries are consumables, and it is normal for the capacity to drop by 20% after 2-3 years of normal use. Instead of worrying about perfect maintenance, it is better to focus more on enjoying the convenience brought by the device. After all, mobile phones are tools that serve us, not "ancestors" that need to be carefully worshipped!
