Nope, its from charging to 100% constantly which accelerates wear massively.

I've had my Lenovo carbon x1 for a few years set to 80% max charge and its battery life is still good.

Battery stats report 480 charging cycles, capacity has dropped only 8 percent from rated.

It’s not charging to 100% that wears batteries out. It’s storage at 100% that does that.

If you charge to 50% and keep it there, it basically last years.

If you use your notebook primarily on AC, battery is charged and kept on “storage” until you unplug from AC. Over the years, this is equivalent to a battery stored on a box.

So, time stored on a box with 50% is better than 80%, which is also better than 100%.

But. If your notebook is used primarily unplugged from AC, that 100% is better than 80%, because you’ll have fewer deeper discharges.

Deep discharges is what form dentrites. Dentrities is what kill lithium batteries.

> If you use your notebook primarily on AC, battery is charged and kept on “storage” until you unplug from AC. Over the years, this is equivalent to a battery stored on a box.

I'm not sure what you mean, by default most laptops will charge to 100% and keep trickle charging it to that level consistently while on AC.

Setting a charge max of 40% would be ideal, but there is point where you want to maintain some level of runtime when removed from AC, so 80% is a reasonable compromise.