Does keeping your laptop plugged in wears off your battery ?

Stop keeping your laptop on the charger all day. You're destroying its battery. Nope, that's completely outdated. To know what really wears a battery out, you need to see how it works. Inside, lithium ions travel from one side, the anode, to the other, the cathode. Their electrons can't go through the inside, so they take a detour through your laptop. That detour is your electric current.

Once nearly every ion has made the trip, the battery is at zero. Plug it in, and they all go back. In practice, it's messier. Small chemical side reactions grab some of the lithium on the anode side and lock it there for good. Less lithium that can move means fewer ions and a smaller battery. On top of that, those reactions build a thin crust that grows over time and slows the ions down.

And the hotter it gets, the more often those reactions happen. A laptop baking in the sun, sitting in a hot car all summer, or on a duvet with its fans covered, that's how you age a battery fast. The second thing that hurts it is the extremes, 0% or 100%. At either end, nearly all the ions are crammed on one side, and the damage speeds up.

Somewhere around 20 to 80% is where it's happiest. So if it's always on the charger, it sits at 100% all day, and I'm wrecking it? Not on most recent laptops. Once it notices you're always plugged in, it stops around 80% by itself. After that, it stops charging and runs straight off the cable.

On a Mac, that's optimized battery charging, already on, or set the charge limit to 80%. On a PC, open your brand's battery app. Some ship with it off. Switch it on and keep it plugged in, no stress. Send this to the friend who unplugs at 100% every time.

Send this to the friend who unplugs at 100% every time.