On Monday, June 3, Apple presented iOS13, the new version of the operating system for its iPhones, which will be available starting next fall. The news are many, starting with the expected “Dark Mode” already introduced last year on macOS Mojave, but one could change the way many are used to charging their iPhone: an option to reduce full recharges, to conserve battery life longer.
Lithium-ion batteries, used in smartphones and laptops, have a longer life if they are not always charged above 80 percent of their capacity. The point, however, is that no one wants to find themselves in the position of reaching the end of the day with the smartphone almost empty, and for this reason it usually proceeds with a full recharge. Apple has thought of a compromise, which could make things better.
In the description of the features of iOS 13 there is the item “Optimized charge for the battery”, with this description:
A new option helps slow down battery aging by reducing the amount of time your iPhone stays fully charged. Each iPhone learns from your daily charging habits, waiting for more than 80 percent to finish charging, until you need to use it.
The principle of operation of batteries has not changed much since the first battery was invented, by the Italian Alessandro Volta, in 1800. The materials with which they are made are obviously different since then and the current technology, based on lithium ions, it is currently considered the best compromise for having efficient and long-lasting batteries (albeit unstable and made with polluting materials).
The first rechargeable batteries suffered from the so-called “memory effect”: as they were subjected to recharging cycles, they lost the ability to charge up to the maximum or to discharge completely. The newer lithium-ion batteries do not have these problems, but they can suffer from premature aging especially if you try to always have them completely discharged before proceeding with a new recharge.
Current lithium-ion batteries also have a maximum charge problem: they can be recharged to 100 percent a limited number of times, then begin to lose their capacity. Things get a little more complicated here, in the sense that it's not just a 0 to 100 percent refill that counts as a maximum charge. If the battery is at 80 percent and five times charged to 100 percent, those single 20 percent charges combined still count as a full full charge.
There are also other factors that affect battery aging. If you always keep it at 100 percent when connected to a charger, the battery can overheat and damage itself further. Smartphones usually have systems to prevent this from happening, for example by stopping charging when 100 percent is reached, and making sure that the phone is powered directly from the charging cable.
The problem is that in the meantime the battery tends to discharge a little anyway, requiring new short charging cycles to keep it at 100 percent. It may therefore happen that at night the smartphone on your bedside table reaches 100 percent, then falls below that percentage and reactivates the charge to return to 100 percent. All these mini charge cycles combined then count as a full full charge.
Lithium-ion battery manufacturers usually recommend keeping between 40 and 80 percent as much as possible. The idea is not to let the smartphone download too much, nor to charge it up to its maximum. If we add to this that the batteries are subject to the outside temperature, with lower performance if it is too hot or too cold, we understand that keeping them healthy is rather complicated. Manufacturers of smartphones and operating systems therefore use various measures to mitigate the problem.
The new iOS 13 introduces a trade-off to still offer 100 percent charge to get you through the day, but reducing the strain on the battery. Apple has developed some algorithms that will take care of keeping the battery at 80 percent during long charging periods, for example those carried out at night. Based on the alarm set on the phone and the time in the morning when you start using it, the system will determine the appropriate time to bring the iPhone from 80 to 100 percent with a single charge cycle.
In other words, the iPhone charging on the bedside table will no longer spend a good part of the night at 100 percent, with mini charging cycles to always bring the battery back to that value when it loses some charge, but within the recommended limit of '80 percent, only to reach 100 percent just before the alarm clock. This should keep the battery healthy and extend its ability to charge at its best.
