Is fast charging damaging your mobile battery? Long-term testing provides the answer

An extensive trial has finally provided a clear answer to a question that many smartphone users have wondered for years, namely whether fast charging harms the battery.

The results show that the difference between fast and slow charging in practice is minimal and far less than most people think.

How the test was conducted

YouTube channel HTX Studio conducted a six-month experiment where 12 smartphones were tested over 167 days and more than 500 charging cycles.

Six of the phones were iPhone 12 models, while the other 6 were Vivo iQOO 7 Android phones.

The phones were divided into three groups.

One group was fast-charged with 120 watts, another was slow-charged with 18 watts, and the last group followed the so-called 30 to 80 rule, where the battery was never discharged below 30 percent and never charged above 80 percent.

This allowed the researchers to measure how different charging methods affected battery capacity over time.

Surprisingly small differences

After 500 full charges, the results showed that fast charging had virtually no negative effect on the battery.

the iPhone models that were fast-charged only lost 0.5 percent more capacity than the slow-charged phones.

For Android phones, the difference was even smaller at just 0.3 percent.

Even the most careful charging methods only made a small gain. Phones that were charged between 30 and 80 percent had 4 percent more capacity on iPhones and 2.5 percent more on Android models after the test.

According to HTX Studio, the difference is so small that it’s unlikely to be noticeable in everyday use, especially since most people replace their phones after two to three years anyway.

When is a battery change necessary?

The test concludes that users will first notice a noticeably shorter battery life when the capacity drops to around 85 percent.

When the battery reaches around 80 percent, a change is recommended. Many modern phones automatically adjust performance when the battery gets low to avoid sudden shutdowns where a new battery could restore the original performance.

HTX Studio’s conclusion is clear: For ordinary users, it makes almost no difference whether the phone charges quickly or slowly. The important thing is to charge in the way that best suits your routine.

The so-called ideal charge between 30 and 80 percent can extend battery life slightly, but the difference is marginal.

In practice, this means that you can safely charge your phone overnight or use fast charging without worrying about damaging the battery.