Is it okay to keep your smartphone charged all night while we sleep or will it ruin the battery?

Night-time charging battery
Almost all of us when we go to sleep we charge our cell phone, so as to keep it ready and charged the next day, assuming that this habit does not cause problems for the health of the battery. In reality, in modern smartphones there is a serious problem with lithium ion batteries, which as everyone has now noticed, are not made to last forever.

When you run out of charge and connect your phone to the charger, it begins a charging cycle that lasts a maximum of a couple of hours. On average, a battery lasts around 400 or 500 cycles before losing capacity and significantly deteriorating its autonomy.

At night, leaving the phone charging while we sleep, perhaps for 7 or 8 hours, after the battery reaches 100% it stops charging thanks to the management system inside the phone’s operating system. Even if your Android or iOS system is smart enough to prevent any overload damage, the problem with continuous charging is heat that is generated, not good for the health of lithium batteries, which will degrade faster.

In the following guide we will show you how to properly charge your phone overnightusing some small tricks or activating the settings inside the phone itself (often decisive for extending the life of the phone’s built-in battery).

READ ALSO -> The phone does not charge: how to fix it

1) Does charging at night damage the phone?

Normal charging doesn’t cause excessive heating even if you keep the phone plugged in all night, but it must remain freshhave space to breathe, without leaving it, for example, closed in a drawer or among the blankets.

So if we can manage the heat when charging at night, there are no battery degradation issues and we can feel free to recharge it while we sleep and leave it plugged in for many consecutive hours. At the same time, however, to increase and keep battery capacity high It is recommended not to charge your phone to 100% as often as possible.

In practice it is always worthwhile keep your phone’s battery charged between 40 and 80 percent, so as to prolong his life longer. This isn’t a convenient option for those who prefer to charge their phone overnight, but it’s something to remember for those who have the option to charge their phone during the day.

Basically, leaving the phone to charge up to 100% does not ruin the battery because the operating system prevents overloads and manages the cycles correctly, but since the act of charging the phone’s battery causes it to overheat, keep it charged all night may reduce its capacity over time.

2) Optimized maximum charging level

To be more specific, ResearchGate found that charging a battery up to 85% maximum leads to a longer lifespan than charging up to 100%.

Knowing that charging up to 100% is not the best practice for battery healthwe can use an app like Accubattery for Android to measure your phone’s battery capacitywhich also allows you to set a sound notification so you know when your phone is charged at 80% or 85% and unplug it (with a “do not disturb” option at night).

To set this type of notification when the battery reaches a certain charge level you can also use aautomation app for android come Macrodroid.

This is possible on Samsung phones and tablets stop charging at 85% in any condition: even if 100% will be shown on our screen, in reality the battery will be at a maximum of 85%, therefore making it much easier to preserve the maximum battery life even after years.

On other phones it is also possible to use a function that charges the phone only until the first alarm rings, so as to avoid overcharging the phone even outside of night time (useful to avoid overloads).

On iPhone the charging process is totally automated and, in the event of problems or overheating, the operating system blocks or slows down the charging process at night, without any interaction from the user (who doesn’t even notice what happened).

3) Minimum charge levels to avoid damage

Furthermore, as explained in the article on How often to charge your cell phone battery to extend its lifeit is important that the phone is charged when the battery drops below 40% and never let it get to 0%.

Furthermore, there is no problem in recharging the phone when its battery still has 50% or 60% autonomy and there is no negative effect in charging early.

Bringing the phone to 0% is never a good thing, since we can run into the opposite problem, that is under voltage. An undervoltage battery may not charge well and will damage (often irreversibly) the phone’s lithium cells, decreasing charging capacity.

4) Differences between normal charging and fast charging

Simple charging (at standard voltages) it definitely is recommended for charging your phone at night compared to fast charging or ultra-fast charging: by doing so we will obtain little heat during the entire process, the battery will recharge calmly (avoiding damage from excessive heat) and we will significantly increase the life of the battery over the years.

Since we sleep on average 7-8 hours even the slowest possible charging (3 hours) is easily compensated by a slow loader, making us find the phone charged in the morning.

For this reason we recommend keeping the fast charging charger near your desk, in your bag or near your phone to charge it quickly during the day (making the most of the speeds of modern phones), saving the slow charging for the night hours.

On this topic we can read the guides on how to disable fast charging on Samsung Galaxy come on how to charge your phone in minutes with fast charging.

5) Nighttime wireless charging

Starting from the assumption that the Wireless charging always generates heat (since it uses radio waves to transmit the amount of energy required for charging), also in this case they apply to the advice we have given you with fast charging via cable: we use slow wireless charging (maximum 10W) ​​at night, in order to avoid damage from excessive heat.

If we want to use fast wireless charging (15-30 W or more) it is best to use it only during daylight hours and when the air is cooler (late afternoon or evening).

For further information we can read our articles on how to use the wireless charger for Android and iPhone smartphones come on how to use wireless charging on your phone (without cables).


The habit of leaving the phone charging overnight may not even be abandoned, but it is best to use only slow and quiet chargers (even wireless ones)so as to generate little heat and still get a nice charged phone the following morning.

Consequently, it is always better to use fast charging, ultra-fast charging and fast wireless charging (greater than 10W of transmitted power) only during daylight hours.

To learn more we can read our guide Should you turn off your PC or cell phone at night?

On the same topic we can read the guides on how to quickly recharge a smartphone battery come on what to do if your phone overheats while charging.


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