Question:

How can a new iPhone 6s have 60% charge after being switched off for several years?

I bought a new iPhone 6s from an online seller. It was still sealed in its original box. When I turned it on, the battery indicator showed 60% charge. According to some sources, a switched off phone loses about 5% charge per month. The iPhone 6s was released in 2015, so it should have been off for at least four or five years. How can it still have so much charge left? Is there something wrong with the battery or the phone?

Answer:

If you have recently bought a new iPhone 6s from an online seller, you might be surprised to see that the battery indicator shows 60% charge when you turn it on for the first time. This seems unlikely, considering that the iPhone 6s was released in 2015, and a switched off phone loses about 5% charge per month. How can a phone that has been off for at least four or five years still have so much charge left? Is there something wrong with the battery or the phone?

The answer is not as simple as it may seem. There are several factors that affect the battery life and performance of an iPhone, such as the battery capacity, the chemical age, the impedance, and the temperature. Let’s take a look at each of these factors and how they might explain the mystery of the iPhone 6s battery.

Battery capacity

The battery capacity is the measure of how much charge a battery can hold relative to when it was new. The iPhone 6s has a non-user-replaceable battery with a capacity of 1715 mAh. This means that when the battery is new, it can provide 1715 milliampere hours of current at a constant voltage. However, as the battery ages, its capacity diminishes, resulting in shorter amounts of time before a device needs to be recharged. This can be referred to as the battery’s maximum capacity.

The maximum capacity of a battery depends on how it is used and stored. For example, charging or leaving the iPhone in hot environments, such as direct sun exposure, can reduce the battery capacity faster than normal. On the other hand, keeping the iPhone half-charged when it is stored for the long term can help preserve the battery capacity.

Therefore, it is possible that the iPhone 6s that you bought was stored in a cool and dry place, with a moderate level of charge, which helped maintain its battery capacity over the years. This could explain why it still has 60% charge left when you turn it on.

Chemical age

The chemical age is another factor that affects the battery life and performance of an iPhone. The chemical age is more than just the passage of time. It includes different factors, such as the number of charge cycles and how the battery was cared for. A charge cycle is the process of using all of the battery’s power, but it does not necessarily mean a single charge. For example, you can use 75% of your battery’s capacity one day, then recharge it fully overnight. If you use 25% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle.

As the battery goes through more charge cycles, it chemically ages, and its ability to deliver maximum instantaneous power, or peak power, may decrease. This means that the battery may not be able to provide sufficient power to the system that needs it, such as the CPU or the GPU, when they are under heavy load. This can result in unexpected shutdowns or performance issues.

To prevent this from happening, Apple introduced a feature called

performance management

in iOS 10.2.1, which dynamically manages the maximum performance of some system components, such as the CPU and GPU, to prevent unexpected shutdowns. This feature is enabled only after an unexpected shutdown first occurs on a device with a battery that has diminished ability to deliver maximum instantaneous power. This feature applies to iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE (1st generation), iPhone 7, and iPhone 7 Plus.

Therefore, it is possible that the iPhone 6s that you bought has a low chemical age, because it has not gone through many charge cycles, and it has not experienced any unexpected shutdowns. This could explain why it still has a good performance when you use it.

Impedance

The impedance is another factor that affects the battery life and performance of an iPhone. The impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied. A battery with a high impedance may be unable to provide sufficient power to the system that needs it, especially when the battery is cold, the device is charging, or the battery is low on charge.

The impedance of a battery increases as it chemically ages, but it can also be affected by temporary factors, such as temperature. For example, a cold battery has a higher impedance than a warm one. This is why you may notice that your iPhone battery drains faster in cold weather.

Therefore, it is possible that the iPhone 6s that you bought has a low impedance, because it has not chemically aged much, and it was stored in a moderate temperature. This could explain why it can deliver sufficient power to the system when you use it.

Conclusion

In conclusion, the iPhone 6s that you bought may still have 60% charge left after being switched off for several years, because it has a high battery capacity, a low chemical age, and a low impedance. These factors depend on how the battery was used and stored over the years, and they affect the battery life and performance of the iPhone. However, these factors are not the only ones that determine the battery health of an iPhone. You can check the battery health of your iPhone by going to Settings > Battery > Battery Health, where you can see the maximum capacity and the peak performance capability of your battery. You can also contact Apple Support or visit an Apple Authorized Service Provider if you have any questions or concerns about your battery.