In discussing how to charge your iPhone battery to extend its lifespan, this article may differ from others. While some might advise against using your iPhone while it's charging, I'll tell you it's okay to do so as long as you avoid overheating. Other articles might suggest a charging range of 20%-80%, but I recommend 25%-75% as the most suitable range. Keep reading to understand why.
Recommended charging methods applicable to phones and certain lithium battery devices:
1. Optimal Charging Range: 25%-75% for Enhanced Battery Life
Several years ago, Apple proposed the theory of "charge when the battery is below 20%, unplug when it reaches 80%" for battery health. While Apple's advice is correct, tests by Battery University on lithium battery charging and discharging show that charging from 25% to 75% is more conducive to extending battery cycle life.
（Image source: https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries）
Although the chart indicates that charging lithium batteries up to 75% and then discharging to 65% minimizes capacity loss, sustaining this state for an extended period is challenging. The same holds for the 75%-45% range. Taking a comprehensive view, the optimal charging and discharging interval is 25%-75%.
2. Safe Usage During Charging: Balancing Convenience and Care
iPhone can be charged while in use, as demonstrated by the direction of the current flow when the charger powers the phone battery. When connected to the power source while being used, the current passes through the screen first, then through other electronic components, and finally reaches the battery. In this scenario, the priority is given to the charger's power, and the battery is only consumed when the phone is executing resource-intensive tasks, such as playing large online games.
So, theoretically, using the phone while charging can reduce the number of battery cycles (complete charge and discharge cycles). However, it's important to avoid overheating, as high temperatures can significantly damage the battery. The working range for lithium batteries is 0-35°C.
3. Shallow Discharge and Charge are Better for the Battery
The depth of discharge determines the number of battery cycles. The less deep the discharge, the longer the battery lifespan. If possible, avoid deep discharges (e.g., below 10%), and frequent, shallow charging is more conducive to extending battery life. Lithium batteries do not have a memory function, so there's no need to regularly discharge to 0% and then charge to 100% to extend lifespan unless you need to calibrate the battery capacity.
4. Methods for Charging an iPhone Overnight Without Affecting Battery Health.
Modern smartphones come with fast chargers, capable of quickly filling up the battery. Many people habitually charge their iPhones overnight, causing the phone to remain at a high voltage full charge state for six to seven hours. In this state, lithium ions precipitate faster, reducing the battery lifespan.
The solution is to choose a smart timer socket or a low-current slow charger. A smart timer socket allows you to set a specific time for power cutoff. For example, if your phone needs around 40 minutes to charge up to 80%, you can set it to disconnect the power after 40 minutes. This not only prevents overcharging of the battery but also saves energy. Another approach is to use a slow charger for overnight charging, such as a 5W low-power charger for iPhones. You can charge your phone with this low-power charger before going to sleep.
These are the 4 latest suggestions on how to charge your cell phone to extend battery life in 2024. We hope these suggestions help you better protect your cell phone battery and extend its life.
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