Is it ok to charge the phone overnight

The very first argument of people who believe that it is ok to charge the phone overnight is that the phone is smartphone. Let's clarify that being a smartphone as description pertains to the software, and not to the hardware. They argue that the absence of heat in the charger when the battery indicator reaches 100% is an attribute of a smartphone, which I object. Even an ordinary phone when plugged with a good charger can become cold after awhile when the battery indicator reaches 100%. The trick is not on the software but on the hardware by using IC, integrated circuit or feedback circuit which cut the the electric current when the battery reaches a specific voltage.

Now, is it safe to charge the phone overnight? There is no perfect charger and no perfect phone. Even the branded phone can have electronic glitch. It's probably 99% safe and not 100%. So better do not charge it overnight.

It is advised that to keep lithium battery at its best condition, never drain it nor make it fully charged. So why make your battery 100% charged? The worst, you prolong the 100% until the next morning. Then they argue, that the battery is as good as it was despite overnight charging. One or three times or more maybe okay but constant overnight charging will definitely shorten the life of your battery or the worst will damage the charging IC of the phone.

However, if you want to charge your phone while sleeping , use timer, a device that automatically cut all the electric current at a certain specific time. The image at the right is an example of a mechanical timer.