Does charging to 100% damage smartphone battery?

Charging your battery to 100% and leaving it plugged in after it's full can shorten its lifespan, says Chao-Yang Wang, director of the Center for Electrochemical Engines at Pennsylvania State University. "The battery will degrade faster if you charge it to 100% than if you charge it at a slightly lower level," he says.

Do not charge the battery to 100% too much

Wang said that if users regularly charge to 100%, the battery can lose 10% to 15% of its capacity compared to charging to 90%. Although this degradation is slow, today's smartphone batteries are quite durable, making it unnecessary to replace them early.

However, this doesn't mean that users should never fully charge their battery. "It all depends on the needs and convenience," Wang explains. If a user has an important day and needs more power, charging to 100% makes sense. Conversely, if you're at home and don't need to use your phone much, charging to 85% or 90% might be a better choice.

Continuous high voltage charging causes the battery to age faster

Dibakar Datta, an associate professor at the New Jersey Institute of Technology (USA), also emphasized that keeping the battery at a high voltage will cause the battery to age chemically faster. In addition, letting the battery go down to 0% is also not a good idea. Datta recommends users to charge when the battery is around 20% and maintain the ideal battery level between 20% and 80%.

Additionally, using a fast charger can also damage the battery over time. Datta argues that slow charging should be preferred because fast charging generates heat, which can degrade the battery. Temperature is also an important factor, as the battery can be damaged if exposed to too high or too low temperatures.

If you're concerned about your battery health, most smartphones allow you to check the battery health in the settings app. If your battery health is below 80%, Datta recommends replacing the battery.