Charging your smartphone at 100% in the long run ruins the battery and reduces its life expectancy. That's why Apple has included a new feature in iOS 13
One of the new features of iOS 13 is the so-called "battery optimization", that is, the optimization of smartphone battery charging that, Apple assures, greatly improves its life expectancy. According to the Cupertino giant, thanks to this optimization, iPhones will suffer much less from one of the most common problems on modern smartphones: the battery, after a few charge and discharge cycles, tends to no longer reach its maximum charge.
In reality, however, more than "optimization" we should speak of "limitation" since behind the memory optimization of iOS 13 there is simply the choice to stop charging the battery at 80% of the total charge. Through an algorithm, however, the user can still use 100% of the charge without affecting the ability to accumulate the maximum charge. How is this possible? With a trick, a stratagem that relies on the complex chemistry that governs the charge and discharge of lithium-ion batteries.
How lithium ion batteries work
We've all experienced it: when we buy a new cell phone and charge it to 100%, the battery lasts a long time, sometimes even more than a day with heavy use. After a while, however, even if we continue to charge the device at 100%, the battery lasts less and less. This is absolutely normal, which is due to the fact that lithium-ion batteries don't like to be recharged beyond 80%. Especially if we use fast charging. By charging the battery beyond 80%, in fact, we very often risk overheating it and damaging it. This is even more true if the smartphone is charged in a very hot place.
The 40-80 rule and the optimization of iOS 13
Most manufacturers of lithium-ion batteries make the same recommendation: always keep the battery charge between 40% and 80%. If we don't let it drain too much, and don't overcharge it, our battery will last much longer and keep its maximum charge for longer.
But Apple knows that many users need 100% battery power to get through the day with their smartphone on. That's why it invented the "battery optimization": during the night the phone is charged up to 80%, then the charging stops automatically so as not to overheat the battery. But since our iPhone knows very well at what time we wake up on average (just track the time of first use in the morning for a few days and make an average), it can also complete the charge up to 100% just before we wake up. In this way, iOS 13 saves goats and cabbages: we wake up with a fully charged battery, but without having stressed it too much overnight.