iPhones shouldn’t be charged to 100%, and here’s why


Phone users have good intentions in charging their phones to 100%, but they may not realize the negative effects of this practice. – Photo by Daphne Linn

When charging a phone, it’s typical to let it keep charging until it reaches 100% due to the mindset of long-lasting battery that the satisfying number provides. However, some research shows that charging an iPhone to 100% is actually harmful to the phone in the long run.


Why is it harmful to charge an iPhone to 100%?

Charging an iPhone to 100% on a regular basis can be damaging to the phone in the long run. The reason for this starts with the type of battery Apple has decided to use for their phones. iPhones have lithium-ion batteries, which mean that they have a certain capacity for charges. So, after a specific number of charges, the battery will start to degrade.

A lithium-ion battery (above) can be found in any iPhone. Although overall reliable, the battery may degrade with extreme power discharges. – Photo by Group Vertical

How can users see how much their battery has degraded?

Almost all iPhone users have degraded batteries. In the Settings app of an iPhone, the user can click on the Battery Health section to view how much their battery has degraded.

Next to Maximum Capacity in the Battery Health settings, users can find how much their battery has degraded simply by subtracting that number from 100. Above, the phone has degraded by 2%. – Photo by Business Insider

How do batteries degrade, and how can that be prevented?

Extreme discharges of battery life greatly affect the battery of a phone. Extreme discharges occur when a user charges a battery to 100% and allows it to drop to 20% or less. Keeping a charge between 40% and 80% is the best way to keep a battery from degrading.

Because of the benefits of keeping a phone between 40% and 80%, charging a phone overnight isn’t a good habit to get into unless completely necessary. – Photo by PCMag

What are the benefits of protecting a battery from degrading?

When the battery of a phone begins to degrade, the charges of 100% have less battery life. So, if a phone’s full battery life was 12 hours, its degraded battery life may be 10 hours. Preventing a battery from degradation will also prevent performance issues that could potentially occur because of a degrading battery.

The above chart shows the battery life of iPhones. These numbers may decrease with degradation of batteries. – Photo by PCMag

Do iPhones have built-in features that help protect battery life?

Yes. Apple has come up with several ways to protect batteries so that they will last longer, creating higher quality, longer lasting phones. In the Battery Health section of the Settings app, Optimized Battery Charging is a feature that stops a phone from charging past 80% until the owner is ready to use it, using data from the owner’s past battery use. Apple also notifies users with battery-related warnings. For example, if a phone is kept charging at 100%, users will receive a notification to unplug their device to protect the battery. Low Power Mode, which turns on when a phone is at 20% or less, may be a frustrating feature to some users. However, it makes the user want to charge the phone which leads to less battery degradation.

Optimized Battery Charging, one of Apple’s unique battery-saving features, is available under the Battery Health settings. – Photo by Apple

Overall, charging an iPhone battery to 100% and letting it drop is definitely a bad habit iPhone users may want to change in order to help their phones last longer and perform better. A degrading battery is undoubtedly something that users should attempt to avoid due to the harmful consequences that may occur.