Charge and discharge your smartphone battery correctly: here’s how not to ruin it

When buying a new smartphone we often ask ourselves how to charge the battery correctly to preserve its life and performance. There are still numerous “urban legends” regarding the practices to be adopted to ensure that thebattery autonomy (i.e. the number of hours it can run before needing to be recharged) and its life cycle (i.e. its overall duration) last as long as possible. It’s a shame, however, that some of these practices – such as charging and unloading it completely – are anything but beneficial.

Most mobile devices currently in circulation are equipped with batteries lithium ion (Li-ion) or ai lithium polymer (Li-po)which are lighter, more efficient and safer than old al batteries nickel-cadmium (Ni-Cd) or to nickel-metal hydride (Ni-MH).

Lithium batteries have the advantage of suffering much less than the so-called “memory effect” compared to the other two types (especially compared to the nickel-cadmium ones). What does this mean? To put it simply, nickel-cadmium batteries needed to be charged only when completely discharged: without this measure they “forgot” their real capacity and, therefore, no longer worked optimally. Since the lithium battery is not affected much by the “memory effect”, charge it to the maximum and let it discharge completely not only is it useless, but it is definitely harmful.


A first factor that can damage your phone’s battery, in fact, is the so-called discharge depth, i.e. the percentage of energy that is consumed before recharging it. The higher the depth of discharge, the more “stressed” the battery will be, with the consequence that the remaining charge cycles will be reduced. Here because It is not recommended to completely discharge the battery before recharging itbut on the contrary, it is good practice keep the charge level between 20% and 80%. This allows you to preserve both the capacity and the life of the battery, avoiding exposing it to too low or too high voltages.


Another factor that could damage your cell phone battery is overloaded, i.e. maintaining it at a high voltage for an excessively prolonged period of time. This causes the formation of lithium deposits on the surface of the electrodes, with the consequence that these reduce the capacity and resistance of the battery. Furthermore, overcharging increases the risk of the battery overheating and exploding.

For all these reasons fully charge the battery or even leave it charging overnight constitutes a big mistake. It is much better to perform short and frequent energy “top-ups”.

Fortunately, smartphone manufacturers are slowly integrating software solutions that block the charging process once the optimal threshold of 80% is reached. The function is an example of this Charging optimization of Apple which, if set to Limit 80%, causes the iPhone to charge up to around 80%. Should the battery charge level fall below 75%, charging will continue until the battery level reaches approximately 80% again. Even the most distracted users, once these “battery-saving” settings are activated, can sleep a little more peacefully.