With the launch of the iPhone 15 in 2023, Apple brought an interesting innovation to battery settings: the optional 80% charge limit. This feature is designed to ensure that battery health is maintained for longer by never charging the iPhone beyond 80%. Since iOS 18, released in 2024, you have even more flexibility: you can now set the charge limit in 5% increments - from 80% to 85% and 90% to 95%.
But how useful is it really? Many iPhone users ask themselves whether activating this option is the right choice. In this article, we will examine whether the charging limit actually has the desired effect and how the battery capacity has developed after a year.
Why a charging limit at all?
To better understand how the charge limit works, it's worth looking at the basics of battery technology. Lithium-ion batteries, which are used in most modern devices such as the iPhone, have a limited number of charge cycles. A charge cycle is counted when the battery has been discharged and recharged by a total of 100% - this can be done either by fully discharging and recharging or by multiple partial charges.
The problem: Batteries wear out over time. If the battery is always charged to 100%, this accelerates the natural wear process. Studies show that batteries last longer if they are kept between 20% and 80%. This is why Apple introduced the charging limit of 80%. But does this really help in practice?
A year with the 80% charging limit: MacRumors' experiences
The MacRumors team tested the 80% charging limit for a year and the results are revealingThe test was conducted on an iPhone 15 Pro Max, which was charged exclusively to 80% from September 2023. After 299 charging cycles, the battery still had a capacity of 94%.
For comparison: Two other iPhone 15 Pro Max models without a charging limit in the MacRumors team performed as follows: 87% capacity after 329 cycles and 90% capacity after 271 cycles.
This means that the iPhone with the 80% charge limit had a 4% higher capacity with 28 fewer charge cycles. A significant difference? Not necessarily. It's clear that the charge limit brings a slight improvement in battery health, but the question remains: is it worth the effort?
The downside of the 80% charging limit
What many people don't realize is that constantly charging to just 80% also brings with it some challenges. The MacRumors tester reports that there were days when the battery just wasn't enough at 80%. Especially if you're on the go all day or don't have a charger handy, the limit can quickly become a burden. There were also situations in which the tester had to take an additional power bank with him to ensure that the battery made it through the day. This shows that while the charging limit protects battery health, it isn't always practical.
What's interesting, however, is that Apple has built in an intelligent system: the iPhone occasionally randomly charges to 100% to calibrate the battery and ensure that the battery measurement remains correct. This function ensures that the battery does not permanently "get stuck" at an 80% state and offers a certain flexibility in everyday life.
MagSafe or USB-C: Which charging mode is better for battery health?
Another factor that affects battery health is how the iPhone is charged. MacRumors' tester charged primarily via USB-C during the experiment, but also occasionally resorted to MagSafe. It turns out that about 70% of the charging was done via USB-C, while 30% was done wirelessly via MagSafe.
Why is it important? Wireless charging generates more heat than traditional charging via a cable, and heat is an enemy of battery longevity. For this reason, charging via USB-C, which generates less heat, can have a positive impact on battery health. So it's not just the 80% charge limit that matters, but also how you charge your iPhone.
How important is the 80% charging limit really?
After a year, it's clear: the 80% charging limit offers a slight advantage when it comes to battery health. But the difference isn't so dramatic that it makes sense for every user. Anyone who uses their iPhone regularly and intensively will probably miss the additional 20% battery capacity.
Another consideration is the duration of use. It is quite possible that the true benefit of the 80% limit will only be felt after several years. After just one year of testing, there is a slight advantage, but the differences are not groundbreaking. It might be worth testing the limit over a longer period of time to better assess the long-term effects.
Optimized charging as an alternative
For most users, activating the "Optimized Battery Charging" function in the settings could be a useful alternative to the rigid 80% charging limit. This function ensures that the iPhone intelligently learns when you charge it and only charges it to 100% shortly before your usual usage time. This means that the battery is not unnecessarily fully charged, which can also save its lifespan - without you having to do without the full 100% when you really need it.
Conclusion: Should I activate the charging limit?
In the end, it depends on your personal preference. If you are willing to give up the full 100% battery life, the 80% charge limit could be an interesting option to extend the life of your battery. For most users, however, the "Optimized Battery Charging" feature may be a more convenient solution to preserve battery health without sacrificing flexibility in everyday life.
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