Woman Who Charged Her iPhone To 80% Daily For A Year Shares Surprising Results On Battery Health

A woman has drawn attention online after sharing the outcome of a personal year-long experiment to test how charging habits affect an iPhone’s battery health.

Even with all the advancements in technology, there’s still one universal frustration that unites smartphone users everywhere — the moment your phone dies when you need it most.

No matter how advanced our phones have become, battery life continues to be a constant battle for users who depend on their devices all day long.

Fortunately, modern smartphones charge much faster than older models and can generally last longer through daily use. Today, we rely on these powerful pocket-sized computers for everything from work to entertainment and navigation, so any improvement in battery life is welcome.

However, Apple has long faced criticism for what many users consider to be underwhelming iPhone battery performance compared to competitors. The company has made steady progress over the years, but the reputation has been hard to shake.

Still, battery anxiety among iPhone owners continues to fuel creative strategies and habits meant to preserve long-term battery health.

Many Apple fans have tried different approaches to prevent their batteries from degrading too quickly. One of the more popular theories is that keeping your iPhone between 20 and 80 percent helps extend its lifespan, since charging to 100 percent or leaving it plugged in for too long is said to strain the battery.

To make this easier, Apple introduced a built-in feature for the iPhone 14 and newer models that lets users set a charging limit — anywhere between 80 and 100 percent — depending on their preference.

This led one iPhone owner to wonder if that feature actually makes a difference over time, and she decided to find out through a simple year-long experiment.

Despite their popularity, iPhones are often criticisied for poor battery life David Paul Morris/Getty Images

According to a post she shared on the MacRumors forum, the woman conducted a one-year test with her iPhone 16 Pro Max to see if limiting her charging to 80 percent would preserve battery health better than usual charging habits.

She had actually tried a similar experiment before with her previous phone, an iPhone 15, and decided to repeat it with the newer model to compare results.

Throughout the year, she made sure her phone never dropped below 20 percent and only charged it up to the 80 percent limit. She used a combination of wireless and USB-C charging for convenience and consistency.

The woman claimed she felt after the year-long experiment her battery health was average David Paul Morris/Getty Images

She wrote: "It was fine when home, but if I was out and wanted to use the camera or needed GPS, it often wasn't enough battery."

When she shared her results, she reported that her battery health was at 94 percent after 299 charge cycles — a figure she said was about average for an iPhone after a year of use.

She concluded that her charging habits, while consistent, didn’t seem to make much difference in long-term performance compared to typical charging behavior.

She later added: "I now have two years of data with my ‌iPhone‌ limited to an 80 percent charge, and I don't think it's been worth it."

"My coworker, who also has a 16 Pro Max, did not have an 80 percent charge limit set, and his battery capacity is 96 percent with 308 charge cycles."

Despite feeling that the experiment didn’t bring a big benefit, she revealed that she has since upgraded to an iPhone 17 Pro Max and plans to repeat the test for another year — this time hoping for a clearer outcome.