What happens when you charge your smartphone overnight?

Even though a typical smartphone today is one fine piece of technology, we have struggled to solve one of the crucial problems and that is battery life. No matter how optimally you use your smartphone, it always dies sooner than you expect. And with all the hustle and bustle we go through the day, it’s actually not a bad feeling to wake up to 100% battery on your smartphone. But, charging your smartphone overnight kills the battery right? I am pretty sure you have heard this at least once from someone and there have been a ton of articles on the internet standing for and against this statement. However, which of them is really true? What really happens when you charge your smartphone overnight? Let’s find out.


There are two theories of this practice. One says that Li-ion batteries which are dominant on most smartphones these days have a tendency to overcharge. The other one states that our smartphone is intelligent enough to let go of the current when it reaches 100 percent.


Well, both theories are actually correct in their own sense. A spokesperson from Anker, the famous power bank manufacturer highlighted that “Modern smartphones are smart, meaning that they have built-in protection chips that will safeguard the phone from taking in more charge than what it should. “Good quality chargers also have protection chips that prevent the charger from releasing more power than what’s needed. For example, when the battery reaches 100%, the protection hardware inside the phone will stop current from coming in and the charger will turn off.”

So if we go by Anker’s theory, there is absolutely no harm in keeping your smartphone plugged into the socket overnight.


However, there is a different take on this as well. An article on Battery University explains how a Li-ion battery behaves when the current is passed through it. In general, Li-ion batteries do have a tendency to overcharge if exposed to the current for a prolonged period of time. Not only this, as soon as your smartphone hits 100 percent on battery, the voltage drops significantly. So your smartphone drains battery naturally. Now to keep up with this, your smartphone will continue to provide some current to the battery to keep it at 100 percent. This is called ‘Trickle Charge’.

In order to prolong the life of Li-ion batteries, it is best to keep it under 30 to 70 percent of charge. On average, a smartphone battery has about 400 full charge cycles i.e. from 0 to all the way to 100 percent.


So what should I do?

Both the theories are contradictory to each other and hence might confuse you to some extent. So let’s break it down.

Charging your smartphone overnight does have an impact on the battery life, but, it is extremely negligible. In fact, your smartphone’s battery starts deteriorating ever since the first time you charge it. That’s how it has always been. So even if you follow the second theory rigorously, you will notice a significant drop in your smartphone’s endurance in about 1-2 years after you purchased it. And that is actually not bad. Our smartphones are meant to be used over time and there is a life cycle to everything on this planet so it’s absolutely normal if you witness significantly shorter days on a full charge after a point of time. Assuming everyone of us here are normal smartphone users, charging your device overnight doesn’t really harm so take it easy and enjoy the bliss of that 100% battery every morning before it drops to 99% real quick. Cheers!

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