A woman carried out a year-long experiment with her iPhone 16 Pro Max, strictly sticking to an 80 percent charge limit to see how it impacted the battery’s health.
Only charging your phone to 80 percent is commonly recommended to improve your phone’s battery life span.
If you’re an iPhone user, you can even set a limit, restricting your phone from charging past 80 percent.
But does following the 80 percent rule, actually make a difference? One woman tried it for a whole year with her iPhone 16 Pro Max to find out.
DISCOVER SBX CARS – The global premium auction platform powered by Supercar Blondie
She didn’t let her iPhone charge past 80% for a whole year
As phone’s age the battery degrades, meaning there’s less time between charges.
There are plenty of hints and hacks that claim to boost your phone’s battery, like not swiping apps closed or placing your device face down when not in use.
Amanz
Another touted method to improve your battery life is to limit charging to just 80 percent and one woman put it to the test for an entire year.
In a post shared on the Mac Rumors forum she revealed that she had done a similar test the year before with her iPhone 15, and decided to give it another go with her newer handset.
As well as only charging up to a maximum of 80 percent, she also tried to avoid letting it fall below 20 percent before charging.
And admitted that it hadn’t always been easy, and that keeping in with the strict limits had been ‘inconvenient’ .
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,” she revealed.
To charge her iPhone 16 she used a ‘50/50 split’ of MagSafe wireless charging and fast-charging via USB-C.
Click the star icon next to supercarblondie.com inGoogle Search to stay ahead of the curve on the latest and greatest supercars, hypercars, and ground-breaking technology
Here’s what the results showed after 12 months
The woman ran her year-long experiment from September 2024 to September 2025 and then posted her findings on Mac Rumors.
In the post she revealed that after a year of charging to no more than 80 percent, her battery was at a not-too-shabby 94 percent capacity after 299 charge cycles.
However, she went on to say that she believed the battery capacity to be ‘about average’ regardless of charging habits.
Rohit Sharma
“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,” she said.
The woman added that over she didn’t think it was worth it, and that her results had been ‘disappointing’.
But just to test the theory, she had begun another year-long experiment, this time with an iPhone 17 Pro Max.
And I guess we’ll find out how that went in about six months time.
Timeline of the iPhones
2007: First generation is announced by Steve Jobs
2008: iPhone 3G is launched with 3G connectivity and the App store
2010: iPhone debuts with Retina Display and new glass/steel design
2011: Siri is introduced
2013: Touch ID is introduced with the 5S
2016: The headphone jack is removed with the 7 and 7 Plus
2017: Face ID is introduced
2020: iPhone 12 series introduces 5G
2024: The 16 series introduces enhanced on-device AI features and camera controls
2025: iPhone 17 is introduced with a redesigned ultra-thin form factor, next-generation AI capabilities, and a more advanced camera system
DISCOVER SBX CARS:
The global premium car auction platform powered by Supercar Blondie