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Why You Should Unplug Your Phone When It’s Fully Charged

Many of us put our phones on the charger at night to wake up to a fresh, fully charged phone in the morning. But could this habit be causing damage to our phones over time? You might be surprised to find out that most modern smartphones will have sensors that prevent any overcharging from happening. Even so, there are still some issues you could run into if you leave your phone on the charger after it is fully charged. 

You should unplug your phone once it has reached 100% charge. If it is left on the charger for longer, or overnight, it will enter into a “trickle charging” cycle which can accelerate the deterioration of the rechargeable battery, shortening it’s lifespan. 

To keep your battery at full capacity for longer, you should start learning about what makes batteries degrade over time. This, combined with smart charging habits, can help you keep your phone operational for years without too many power issues. Read on to discover how you can keep your phone batteries healthy and why they lose capacity.

“Trickle Charging” and Its Effects on Batteries

The lithium-ion battery installed in your phone is meant to be recharged. Phone companies use these types of batteries for their small form factor and relativity fast charging speed.

But they don’t last forever. This means you need to know what kind of charging habits will degrade your battery more quickly. One way you can decrease your phone battery’s lifespan is to allow your phone to trickle charge.

Trickle charging is when you leave your phone on the charger after it has reached a full charge. Modern smartphones and other devices have sensors to stop charging once 100% has been hit to avoid overcharging. This means that once you hit this mark, the charge will cut off, leaving your phone to pull power from the charged battery (more on that in our guide) . But, once the battery falls below 100%, it starts drawing power from the charger again.

This creates a constant cycle of charging and pulling from the battery. This can eat up the number of cycles your battery has left at a higher rate than usual.

Once a battery starts to degrade, its capacity starts to disappear. This is why it always seems like old phones charge slower and drain quicker; they have gone through too many cycles. 

To preserve your battery’s life, you need to start removing your phone from the charger once it has become fully charged. This can be a hard habit to get into, especially if you like leaving your phone to charge overnight. 

Effects of Charging your Phone Overnight

iPhone Battery Fully Charged

What most don’t understand about Li-Ion batteries is that it is the act of charging that degrades the battery. The limitation of these types of battery is how many charging cycles they can go through before they start losing capacity.

By design, there are only a limited amount of these cycles available for your phone to use before you will either need to replace the battery or the phone itself. 

So if you are in the habit of changing your phone overnight, you can see how this can damage your phone’s life cycle. If you leave it on the charger after it is fully charged, you are essentially always charging your phone due to the trickle charging. This can have a much heavier impact on your battery’s life than just allowing your phone to drain naturally. 

If you think about how long we sleep a night, this adds up. An average healthy human will spend almost 1/3rd of their lives snoozing away.

That’s about 2-3 months out of any given year. So while your phone is not in danger of overcharging, allowing it to trickle charge can have some consequences. While it may not be as noticeable as you think, leaving your phone charging overnight can shave away a year of phone use. 

The average lifespan of a modern smartphone is around three years. So while it is true that your phone may be fine if you leave it overnight, make no mistake that some damage is happening. It won’t overload your battery, but it will degrade it over time. If you intend to get full use of your phone, you will need to change your charging habits and learn how to maintain your battery life. 

How to Maintain Battery Life

Now that we know what terrible charging habits look like, we can try and tackle them head-on. For most of us, the act of just leaving your phone on the charger is proven to cause wear on your battery over time, and similar to whether you should wear glasses or not while looking at your phone (our guide), there are a few ways to fix it.

This is especially the case if you are letting your phone charge overnight. But how do we fix these issues?

Here are some better habits you can start today:

  • Charge Sparingly – The reality is, most modern phones only need 2-3 hours to fully charge, so try and only charge when you need to. 
  • Active Use Vs. Idle – Your phone will discharge quicker when in use, like during the day. When you are sleeping, it is idle, meaning it will drain the battery slower.
  • Turn Off When Not Needed – When necessary, turn off your phone to avoid having to keep it always charged.
  • Use Alternative Devices – Our phones have replaced a lot of other devices. You can always say, use an alarm clock like this one from Amazon, instead of always relying on your phone to wake you up. 

On really clever tactic is to always charge your phone in the same spot, but to use an external timer like the TECKIN Smart Plug (on Amazon) to make the charger only kick on from, for instance, 3 to 5 AM.

That way you phone has time to fully charge in the early morning before you need to start using it for the day, but it’s not sitting on the charger trickle charging for 5-6 hours per night.

There are lots of smart ways you can use your phone while at the same time making sure you are not doing too much damage to your battery. Smartphones like the Samsung Galaxy (on Amazon) have made our lives so much more convenient. It is easy to rely on them for a lot of daily activities.

We check our emails, send texts, read the news, watch videos; the list goes on. All these use chips away at the number of cycles left in your battery. 

How Batteries Degrade Overtime

Lithium-Ion batteries don’t last forever. While it is true that battery technology is improving, so too does computation power. This means that even though batteries are getting more robust and more efficient, their power gets eaten up by more power-hungry hardware. To better understand the life cycle of a battery, you should know how a normal battery degrades.

Batteries usually have a life span that is measured in cycles. These cycles are how many times the battery can be discharged to 100% of its capacity. This doesn’t just mean going from 100% to 0%, though. A cycle can be broken up over time. Say you charged from 30% – 100%, then the next day 70% back to full charge. This would be one cycle.

Most Li-Ion batteries will have about 400-500 cycles before the battery’s capacity and operation starts to fall. For the average user, this will usually be around 2-4 years. A little bit less if you are always charging your phone, though, which can take away about a year of use.

Unfortunately, most manufacturers these days don’t make it easy to replace a battery. This is mostly a safety issue as Li-Ion batteries can be dangerous if not handled correctly.

We all remember the plague of incendiary Samsung phones from a few years back; these batteries can be explosive. Keep in mind that even though most tech companies lock you out of an easy replacement, doesn’t mean you can’t do it on your own.

There are kits available, like this iPhone 7 battery replacement kit (on Amazon), but they require a certain amount of tech know-how. It is worth noting that in most cases, replacing a battery at home will void any type of manufacturer’s warranty. But if you have an older phone, this can be a great way to extend its life. Parts for older phones will be cheaper as well. 

Wrapping Up

While most phones and chargers are designed to cut off the power when you are at a full charge, you still need to be wary when you leave your phone on too long.

You might not have to worry about overcharging, but you will need to worry about trickle charging. The best way to prevent this from happening is by changing your charging habits.

And whether or not you use a wireless or wired option isn’t going to shift things too much. Check out our other article on using both wired and wireless charging at the same time, but note that the high level summary is: you can’t!

If you tend to leave your phone charging overnight, you may be causing unneeded degradation to your battery. Normal batteries can last anywhere from 2-3 years, but you can be missing out on a whole year of use with improper charging. Understanding how your battery operates and its life cycle can help you keep your phone in operation for longer.