Does it help to limit the iPhone’s charge to 80%? These tests give us answers

One of the most recurring debates about the iPhone is whether limiting the maximum charge to 80% really extends the battery’s lifespan. This option, introduced by Apple with the iPhone 15 models in 2023, prevents premature battery degradation. However, does it work as we expected? The answer is yes, but with nuances.

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A whole year without exceeding 80%

Juli Clover, editor at MacRumors and happy owner of an iPhone 15 Pro Max since September 2023, decided to activate the option to limit charging to 80% from day one, and remained committed to this setting for a full year. Let’s remember that this limitation is designed to preserve battery health in the long term, as continuously charging it to 100% can accelerate its degradation.

During this time, Clover’s iPhone went through 299 full charge cycles, and the maximum battery capacity at the end of the period was 94%. “Interestingly, for most of the year, the battery stayed above 97%, but it started to show a more pronounced drop in the last few months,” he explains in his article.

For reference, other Macrumors writers shared their battery data after a year of use. Without enabling the battery charge limitation, one of them had a capacity of 87% after 329 cycles, while the other, with 271 cycles, showed a capacity of 90%.

At first glance, the numbers reveal a slight difference: Clover, which limited its load to 80%, had 4% more capacity compared to the second case, although with 28 fewer cycles.

Before jumping to conclusions, it is important to remember that not only the amount of charge affects the battery’s lifespan. The temperature at which the device is charged, the type of charger (MagSafe or USB-C), and the number of cycles are also crucial factors. Colver, for example, primarily charged his iPhone with a USB-C cable, avoiding the additional heat generated by wireless charging. Additionally, he charged the device in a room at 22 ºC, which undoubtedly has a direct effect on the battery’s good health.

At this point, Clover explains that this difference does not seem significant enough to justify the inconvenience of keeping the battery at 80%. She often found herself without enough battery during the day or was forced to charge the phone multiple times to avoid running out of power.

Is the 80% limitation effective?

Although the test indicates that there is an improvement in battery health by keeping it limited to 80%, the question that arises is whether it is really worth it. Over the course of a year, the benefit has been modest, but here it is most likely that the true results will be observed in the long term, in two or three years.

If we aim to maximize the battery life of our iPhone, perhaps the option to limit the charge to 90%, available with iOS 18 on the iPhone 15 and the new iPhone 16 (with its larger battery), might be a more balanced alternative. More daily autonomy without compromising the battery’s health. All in all, what seems clear is that the system is effective.

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How effective? The truth is that we cannot fight against the physics and chemistry of lithium-ion batteries. They degrade with use, and to some extent even without use. The components age and performance decreases. Does this limitation compensate at the charge level? This is a very personal answer, but, in any case, it will depend on how long we want to use the iPhone without considering a battery replacement.