Why does your phone stop charging at 80%?

You plug in your phone, and it stops at 80%. Is it broken? Usually not. There are three different reasons it can happen.

One. A limit you chose. Some phones let you set a charge limit, like 80%. The phone charges close to it, then stops. Two. A learned routine. If you charge overnight, the phone can learn when you usually unplug. It waits at 80, then finishes just before you wake up. Three. Heat. A battery warms up as it charges. If it gets too warm, the phone may hold it around 80%, and continue once it cools down.

So why protect the battery at all? Phone batteries wear faster when they sit full for a long time, and when they get hot. Over the years, that wear shrinks how much the battery can hold. Pausing at 80 cuts the time spent full, and that helps to slow the wear.

Need 100% today? Your battery settings let you change it. And charge somewhere it can stay cool. Not under a pillow, and not in the sun. 80% is not a fault. It’s your phone looking after its battery.