Does charging your phone to 100% ruin your battery?

"A battery will degrade faster if you charge it to 100% versus a little bit lower state of charge," Chao-Yang Wang, director of the Electrochemical Engine Center at Penn State University, told HuffPost.

Keeping your phone plugged in at full charge keeps the battery at high voltage, which speeds up chemical aging, according to Dibakar Datta, an associate professor at the New Jersey Institute of Technology.

Wang added that consistently charging to 100% could cause the battery to deteriorate 10% to 15% faster over its lifetime compared to charging it to 90%. While not a drastic difference, it is noticeable.

This degradation is gradual, however, and modern phone batteries are durable. "[Batteries] last, probably, longer than the other features of the phone," Wang said. Most users will likely upgrade their phone for reasons such as a broken screen or outdated camera quality before battery issues arise.

A smartphone is charging. Photo from Unsplash

While charging to 100% is not ideal, it is not something to avoid entirely. Wang suggested that if you need the extra battery life, for example, when traveling, a full charge is fine. But for everyday use, charging to 85% or 90% can extend battery lifespan.

Datta warned against letting your battery regularly drop to 0%, advising users to recharge when it hits around 20%. Frequently draining the battery can impair its ability to hold a charge. Keeping your phone between 20% and 80% is generally the optimal range.

Wang also noted that extreme temperatures can be more damaging to battery health than charging to 100%. High or low temperatures are particularly harmful. When it comes to charging speed, Datta recommended slower charging. Fast charging generates heat, which can degrade the battery over time and, in extreme cases, lead to dangerous overheating.

To monitor battery health, most smartphones allow you to check in settings, or you can visit an expert at a store like Apple or Samsung. If your battery health drops below 80%, consider a replacement, Datta said.