Is fast charging bad for your smartphone battery? Expert breakdown

Robert Haba
Robert Haba
3 min read
Is fast charging bad for your smartphone battery? Expert breakdown
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30 minutes to fully charge the battery? A growing number of cellphones can be fully charged in less than an hour. Does this rapid charging, however, harm the battery? This has been examined in an experiment, which yields an unexpected result.

30 minutes to fully charge the battery? A growing number of cellphones can be fully charged in less than an hour. Does this rapid charging, however, harm the battery? This has been examined in an experiment, which yields an unexpected result.

A Chinese do-it-yourself team called HTX Studio looked into this precise subject. After purchasing ten identical iPhones and ten Android devices, the do-it-yourselfers split them up into groups. A fast-charging power supply unit was used to charge one group, while a slow charger was used for the other. We finally have a response after 500 full charges and six months.

fast charging bad for your smartphone battery

How did they do it?

Two groups of iPhones were created. Apple’s 40-watt power supply was used to charge three gadgets, while the outdated 5-watt power supply was used for the remaining three. To ascertain the typical aging of the battery over time, a second iPhone was left completely uncharged as a control group.

For the Android cellphones, the configuration was the same. The iQOO7, which is unavailable in this nation, was utilized twice: once with 18 watts and once with the maximum power of 120 watts.

The smartphones are fully charged by self-programmed software, which then uses up the battery once again until it is only five percent. After that, the charging procedure resumes. In this way, 500 charging cycles were carried out over a few months.

Is fast charging bad for your phone’s battery?

The enthusiasts looked at the batteries both before and after the experiment. This is due to the fact that not all smartphones have the same battery capacity when they are manufactured. There may be slight variations of less than one percent. The batteries were inspected once more after 500 cycles, and the amount of capacity they had lost was calculated:

  • iPhone (slow charge): 11.8%
  • iPhone (fast charge): 12.3%
  • Android (slow charge): 8.8%
  • Android (fast charge): 8.5%

The outcomes are unexpected. Faster charging caused the batteries in iPhones to lose 0.5 percent of their capacity, but the batteries in Android cellphones even lost 0.3 percent. Only in a lab can these variations be quantified. Therefore, the service life of your battery is essentially unaffected by fast charging.

How to take care of your battery

For the longest potential service life, batteries should be kept between 30 and 80 percent charged, according to another battery myth. For mobile cellphones, some manufacturers even include an 80 percent charge cap.

In order to test this notion, the Baster team charged another set of cellphones to 80% capacity before draining the battery to 30%. The experiment was repeated 1000 times because this was only half of a charging cycle.

  • iPhone (30-80 percent): 8.3%
  • Android (30-80 percent): 6.0%

Therefore, you are actually doing your smartphone’s battery a favor if you never charge it to more than 80%. However, the difference in day-to-day living is negligible even here. Therefore, the experiment demonstrates that you should just charge your smartphone whenever it is most convenient for you rather to spending a lot of time and effort doing so.

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Founder · Editor-in-Chief
Robert Haba is the founder and editor-in-chief of Droid Tools. A lifelong gadget enthusiast with over a decade following the Android ecosystem, he built this publication to cut through the noise and give readers honest, real-world coverage of the tech they actually use.

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