Does fast charging damage the mobile battery? Long-term test comes with a clear answer

A new comprehensive test from YouTube channel HTX Studio set out to investigate whether fast charging actually shortens smartphone battery life.

Over a period of 167 days, six iPhone 12 devices and six Vivo iQOO 7 Android models were tested under different charging conditions.

The results indicate that for most users, concerns about battery wear at high charging speeds are unfounded.

The test was conducted with over 500 complete charge cycles, which corresponds to approximately one and a half years of regular usage.

One group of phones were consistently fast-charged with up to 120 watts, another group charged slower with a maximum of 18 watts, and a third followed the so-called 30-80 rule, where the battery is always kept between 30 and 80 percent charge.

Small differences between fast and slow charging

The measured differences in battery capacity after 500 cycles were minimal.

On the iPhone devices, fast-charged batteries lost on average only 0.5 percent more capacity than those that were charged slowly.

On the Android side, the difference was just 0.3 percent.

In contrast, the more gentle 30-80 method showed a slight improvement in battery capacity.

Here, iPhones achieved 4 percent more capacity compared to those charged to 100 percent.

For Android, the improvement was 2.5 percent.

This suggests that a specific charging strategy can provide slightly longer battery life, but for most people the gain will hardly be worth the effort.

When should the battery be replaced?

HTX Studio estimates that the performance of the phone will only be noticeably affected when the battery capacity drops to around 85 percent.

When it reaches around 80 percent, a battery change is recommended.

Many newer phones automatically throttle performance when the battery is low to avoid sudden shutdowns.

However, battery replacement is often a cumbersome process in modern phones where the battery is built in and fixed.

The conclusion from the test’s backers is that regular users should charge their phone in the way that fits best into everyday life.

In practice, the difference between fast and slow charging is so small that it should not be decisive.

Instead, the number of charging cycles and how long a device is used should be of the utmost importance.