With the iPhone 15 and iPhone 15 Pro, Apple has added a new battery management feature through which users can charge these phones up to a maximum of 80% instead of 100. It is also possible to charge these phones up to 80% instead of 100%. ‘show charge cycles in battery settings. These features have been carried over to the recently released iPhone 16 lineup.
Why stop charging at 80%? This has to do with battery chemistry and the effects of charging over the long term. A lower percentage results in fewer complete charge cycles, which helps extend battery life. But 80% charge means you actually have less charge on your phone for your daily use. So the daily sacrifice is worth the long-term effect? We wanted to know.
Macwelt (igamesnews’s sister site in Germany) conducted a survey on Facebook Germany, asking readers to post screenshots of their battery settings and report their charging behavior, whether they always or almost always charge 100% or only 80%. In less than 24 hours, we received over 100 actionable responses.
To visually assess the influence of charging behavior on battery health, we presented the responses in a combined box and Beeswarm plot.
The two colors or lines on the Y axis represent data points in the two categories, people who only charge their iPhone to 80% and those who charge it to 100%. The number of points indicates how many people with the respective battery capacity we counted in each category. We counted 56 users who charge their iPhone to 100% and 46 users who only charge to 80%. The two groups are not the same size, but close.
Overlapping boxes in the chart show cumulative analyzes of the data. The 80% category tends more toward 100% capacity – it seems that users who charge their iPhone to 80% tend to have a healthier battery in the long run.
We tested this hypothesis using a T-test, a common statistical method for proving that two independent groups differ significantly from each other. If the P value is less than 0.05 (less than 5%), the two groups differ significantly. If the P value is higher, the studied factor (in our case, charging behavior) does not influence the collected data.
We calculated the T test once with all 102 data points in the table and obtained a P value of 0.047121 (4.7121%). In the second calculation, we filtered out all data points for which charge cycles were less than 140, because the battery cannot be expected to age significantly up to 140 charges. Here we got 89 data points, which is six fewer data points in each category. But even with this data, the calculated P value was 0.047547 (4.7547 percent). It can therefore be said that charging behavior has a statistically significant influence on the health and longevity of the battery.
Based on our data, we can confidently say that users who do not charge their iPhone to 100% are saving battery life through this behavior. The maximum battery capacity decreases a little more slowly when charging to 80 percent than when charging to 100 percent.
For more information, you can find out how to change your iPhone correctly.
This article was originally published on our sister publication Macwelt and has been translated and localized from German.
