There’s one thing iPhone users have in common: They charge their phones overnight. Whether it’s a Lightning cable, MagSafe stand, or wireless charging mat, most people have a charger on their nightstand so they can wake up to a fully charged iPhone. One common question many people ask is, "Is it bad to charge your iPhone overnight?"
This is a very commonly asked question, but what’s the verdict? Generally speaking, leaving your iPhone plugged in overnight should not affect its long-term durability. In fact, it’s not possible to "overcharge" your iPhone battery, nor will it overheat or damage any components. But, by keeping your device plugged in all the time, you might reduce the battery’s maximum charging capacity.
In this article, we’ll answer all of your questions about charging your iPhone. You’ll learn how iPhone batteries work, what to consider when leaving your device plugged in overnight, how to take care of your iPhone’s battery, and how to extend its life.
Could Charging Your iPhone Overnight Overcharge its Battery?
The short answer is NO. So, don’t fret if you leave your iPhone charging overnight, because you can’t overcharge its battery!
In the past, batteries used to be affected by how you charged them, but that is no longer the case. The Apple lithium-ion batteries used today come with optimized charging — designed for great battery power and longevity.
If your iPhone is running the latest iOS version, there is little to no chance of its battery overcharging thanks to the charging cycles of the Apple lithium-ion batteries (we’ll discuss this more in the next section.)
How Do iPhone Batteries Work?
iPhones, like many other smartphones and electronic devices, use lithium-ion batteries. The primary reasons for this choice include their high energy density, small size, and relative longevity.
Lithium-ion batteries work on the principle of moving lithium ions from one electrode to another. When the battery is charging, the ions move against their natural gradient, storing energy in the process. During use, the ions flow back to their original position, releasing this stored energy.
However, lithium-ion batteries have a downside. They tend to degrade over time. With each charge cycle (a full discharge from 100% to 0% and back to 100%), the battery’s capacity to hold charge diminishes slightly. This is because the constant movement of ions leads to physical changes in the battery’s structure, affecting its overall efficiency.
iPhone batteries work in two charge cycles. Basically, you complete one charge once you’ve used (discharged) 100% of your battery’s capacity. This may not necessarily happen during one single charging session. For example, you may use 75% of your battery one day, then fully recharge it overnight.
Here’s how the two charge cycles work:
- Stage 1 – Fast Charge: Charges your device’s battery quickly and lasts until your battery reaches 80% of its capacity.
- Stage 2 – Trickle Charge: Eases the electrical current to increase your device’s battery lifespan.
It is, however, pretty easy for the batteries to overheat, which can cause them damage. That’s why a battery usually charges from 0 to 80 percent quickly then slows down when charging from 80 to 100 percent.
What to Consider When Leaving Your iPhone Plugged in to Charge Overnight?
When leaving your iPhone plugged in to charge overnight, heat generation should be one of your primary concerns. As the lithium-ion batteries in iPhones don’t like high temperatures, the heat produced from extended charging could potentially degrade the battery health over time.
You can mitigate this by removing your iPhone’s case during charging, which can help dissipate the heat more efficiently.
Apple says that removing certain cases from your iPhone before charging can help keep its battery healthy.
That’s because some styles of cases may generate excess heat, which can affect your battery’s capacity.
This could be due to the thickness of the case or the material it’s made from.
Materials such as leather, for instance, are better insulators than silicone, making your iPhone more likely to overheat while Charging overnight.
Apple says: "If you notice that your device gets hot when you charge it, take it out of its case first."
How to Extend the Life of Your iPhone’s Battery?
If you often find yourself plugging in your iPhone to charge it overnight, you may want to consider utilizing “Optimized Battery Charging” to extend its longevity. This feature allows you to preserve your device’s battery life by learning your charging habits and adjusting accordingly.
For example, if you typically charge your phone overnight and then unplug it at the same time every morning, your iPhone will learn this charging habit. It will then delay charging the battery beyond 80 percent until the final hours of the morning so the battery will spend less time at 100 percent — reducing stress on the battery. If you have a set routine each day, this is a really cool feature to take advantage of!
Optimized battery charging is enabled by default on all iPhones running iOS 13 or newer. To ensure that the feature is enabled on your iPhone:
- Open the Settings app on your iPhone.
- Select Battery.
- Tap on Battery Health & Charging.
- Turn on the switch next to Optimized Battery Charging.
How to Take Care of Your iPhone’s Battery?
There are many different ways to keep your iPhone’s battery healthy. The following are six key battery preserving tips:
- Enable Optimized Battery Charging: As mentioned above, this feature can reduce battery strain by preventing your iPhone from staying at 100% charge all night.
- Don’t charge your iPhone to 100%: iPhones are not designed to spend long periods of time at full battery capacity. Apple recommends charging to only 50% regularly, as storing your device at maximum capacity for an extended amount of time can result in shorter battery life.
- Remove certain cases during charging: If your case makes your iPhone hot during charging, consider removing it.
- Don’t let the battery drop to very low capacity: It’s not a good idea to overcompensate and let the battery completely discharge. The lower capacity when you shut down, the greater the risk of total discharge — single digits are considered a jeopardy.
- Avoid high and low temperatures: Battery cells are sensitive and any extreme temperatures, hot or cold, can cause internal and physical damage. Don’t leave your iPhone in the sun or a very cold, unheated area for any length of time.
- Keep software up to date: Apple’s solution to most things is to always update your software. It’s a good idea to keep iOS up to date — in order to take full advantage of any battery optimizations added with recent updates.
- Is it bad to leave your iPhone charging overnight? Could you overcharge its battery?
Leaving your iPhone plugged in overnight should not affect its long-term durability, and it’s not possible to overcharge its battery. But, by keeping your device plugged in all the time, you might reduce the battery’s maximum charging capacity.
- How do iPhone batteries work?
iPhone batteries work in two charge cycles — you complete one charge once you’ve used (discharged) 100% of your battery’s capacity, but this may not necessarily happen during one single charging session. You may use 75% of your battery one day, then fully recharge it overnight.
- What should you consider when leaving your iPhone plugged in overnight?
The only thing to worry about should be keeping the battery’s temperature in check. iPhone work best at 0° to 35° C (32° to 95° F) ambient temperatures. Storage temperature: -20° to 45° C (-4° to 113° F).
- How can you take care of your iPhone’s battery, and extend its life?
Your best option is to ensure that the Optimized Battery Charging feature is turned on, as this allows you to preserve your device’s battery life by learning your charging habits and adjusting accordingly.