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Is it Bad to Charge Your Smartphone Overnight? We'll Tell You

Is it Bad to Charge Your Smartphone Overnight?
Many smartphone users say that charging their phones overnight degrades the battery and reduces its life. But how much of this statement is true? In this Techspirited article, we will study the working of a common cell phone battery, and debunk the myth once and for all.
Techspirited Staff
Last Updated: Mar 28, 2018
Quick Fact
Older phones contained Nickel-Cadmium batteries which displayed a strange phenomenon known as the 'memory effect', wherein, a battery that was charged without fully draining it first would not charge to 100%, but to a previously fixed memory point. This gave rise to the rumor that even NiMH, Li-ion, and Li-Po type of phone batteries had to be fully drained before going for a charging session.
Smartphones have become an essential part of our everyday lives, being by our sides all the time and helping us in communication, managing bank accounts, and a whole lot more. However, a smartphone is only useful as long as its battery is functioning well. It is a common practice for smartphone users to charge their phone for long periods, especially while the user is sleeping, but is charging your phone overnight bad for the battery? Let's find out.
Effects of Charging Li-ion/Li-Po Batteries Overnight
Nowadays, most smartphones contain Li-ion batteries. And each of these batteries have a limited lifespan, or a specific number of charges they can take before they stop working. The number of charges can increase or decrease depending on how you use the battery. Heat and high-voltage charging are the main causes behind the decrease of a battery's lifespan. High voltages are usually kept away by good chargers due to a mechanism that lowers voltage to enable charging without damage. However, the user must keep an eye on the phone heating up, which usually occurs during deep/long charges.

The myth that charging a phone from empty to full for a long time originated from the time when mobiles used Ni-Cad batteries. Older phones that used Nickel-Cadmium batteries would work better with long or deeper charges, unlike their Li-ion/Li-Po counterparts. Normally, Li-ion/Li-Po batteries have around a thousand charge cycles (one charge cycle is approximately one complete discharge and recharge to 100%), before they reduce their energy-holding capacity.
Correct Charging Process
Any smartphone, be it an Android, Apple, or any other model that contains Lithium-ion batteries has advanced circuitry that stops the battery from getting overcharged. However, leaving the phone on the charger for long hours on a daily basis can gradually degrade the battery and lessen its life.

Ideally, one should let the phone's battery discharge to 60%, and then charge it back to full. This is because charging a lithium-ion battery from empty to full in one stretch heats the battery and decreases its lifespan by gradually altering the chemical structure of the material in the battery. It is advised that you take the phone off the charger once it reaches 100 percent. If possible, try to charge your phone during the daytime so that you can plug it off at the right time.

Draining the battery completely and giving it a deep charge once in a few months is alright, as it does not cause significant damage. In fact, it can be used to recalibrate the battery gauge in the phone, which might be showing faulty readings.

It is important to note that a full discharge actually means a battery that has reached around 5-10% of its energy capacity. If the battery were to truly discharge to 0%, it would get damaged permanently, and would never be able to recharge again. This means that when your phone dies out after indicating an empty battery, it is the safety cutoff that is indicated in order to protect it from damage.
Tips to Prolong Battery Life
  • Extreme cold or hot weather can drastically affect the performance of the battery. It's best to keep your phone in a temperature of around 63 degrees Fahrenheit.
  • It is better to charge your phone in short bursts everyday, rather than draining the battery completely before giving it a full charge.
  • Turning off your phone once in a while, will give the equipment some rest and increase the life of the battery.
  • Never use cheap knockoff brands of chargers, as they damage the battery life and increase the risk of fires and electrocution. The use of off-brand variants is passable, but your best bet is to stick with original company chargers.
  • Disuse of the smartphone will also affect the life of the battery. So it is important to use the gadget at least once a day, followed by a charging session, if necessary.
  • In Apple phones, one must regularly update to the latest version of the iOS, as they contain performance enhancements for the battery.
  • Shut down the Bluetooth and Wi-Fi when not in use, this will enhance battery life.
  • One can also lower the sound and brightness settings to prolong battery life.
  • Charge your phone only when it needs one, as charging the phone everyday, despite it being full, will damage the battery.
  • Using a wall charger is much better for the battery's health than using car or USB computer chargers.
So, charging overnight does not really ruin the battery, as long as it is not done regularly. The above tips should help your phone battery to last for at least a few years.