Charge laptop while battery is full???

Nowadays, it is believed by many people that leaving your laptop charger connected while the battery is fully charged destroys the battery. The funny part about it is that when you ask one of these people the origin of this believe, it's always the same response; "someone told me so", and it is even funnier how none of them ever has any explanation as to how this happens.

Your laptop battery cannot get overcharged. The laptop charging circuit is designed such that when the battery gets fully charged, current is no longer supplied to the battery. These chargers are automatic in the sense that they are built with a voltage sensor circuit incorporated into them to sense the voltage of the battery under charge. The charger automatically switches OFF when the battery voltage reaches the set optimum level, meaning no power is supplied to the battery at this instant.

If your laptop was on and the battery got fully charged, the laptop will depend on power supplied directly by the charger. At this point, the battery is neither being charged nor is it being discharged. A good number of people resort to disconnecting their laptop chargers once the battery hits 100% to prolong the battery life. This doesn't help at all. It is bad for your battery instead. Here's why: Lithium-ion batteries work in charge cycles. You complete one charge cycle when you’ve used an amount of charge that equals 100% of your battery’s capacity, not necessarily at once. You could use, say 60%, fully charge the battery and then 40%. That makes it one charge cycle. The total capacity of these batteries gradually reduces with every charge cycle. They can retain about 80% of their original capacity after an estimated 1500 charge cycles. Therefore, disconnecting the charger when the battery is full only helps to run it down again thus completing more charge cycles.

On the other hand, leaving your battery connected to the laptop when the laptop heats to temperatures above 50^o C is bad for the battery. Batteries operate by a chemical reaction between negatively and positively charged ions. When the computer heats up, it accelerates this process. This increased chemical reaction reduces the battery life. Thus it is advisable to remove the battery when the laptop becomes too hot to prolong its life.

So it is all just a myth; leaving your laptop charger connected with battery fully charged isn't harmful to the battery. life is too short to waste on monitoring your battery's charge level like your life depends on it 😁