One of the biggest questions around smartphone ownership is whether you should charge your smartphone overnight. No smartphone myth has floated around as long or has become as mainstream as the question of charging overnight. Is it good or bad for the phone? Is it dangerous? Can you overcharge? All of this leads to the question of whether you should undertake this practice. The answer is often dependent on who you ask, but fortunately, science can help make sense of this and find the real truth.
What the Science Says
Let’s clear up one thing right away. No matter what, charging your smartphone overnight, during the day or in the car, is going to degrade performance over time. The lithium-ion batteries that power smartphones (and tablets) have a shelf life that won’t continue forever. They also cut off charging power when a battery reaches 100%.
Each smartphone will have a different “cycle” number that indicates how many zero-to-full charges the battery can handle before it needs to be replaced. The answer is often in the hundreds, so it’s nothing to cause any immediate worry. Besides, you can extend your battery life by not charging to full and not letting it completely drain. That’s not to say you will extend your battery by years, but it will help.
What Manufacturers Say
For its part, Apple recommends any iPhone users on iOS 13 and later utilize its optimized battery charging function to extend the lifespan of your iPhone. This feature will reduce the charge on your battery once it hits 80% in certain situations.
Apple also notes that a battery’s lifespan is “related to its ‘chemical age,’ which is more than just the passage of time.” In other words, Apple explains that battery life is also dependent on external factors, like how well it’s cared for, number of charge cycles, etc. The company has an entire page dedicated to battery-life maintenance that speaks not only to the science but also to the best possible care of your device.
Google, for its part, is in the same boat as Apple and suggests charging your phone “as little or as much as needed.” The company does make specific mention around of charging overnight starting after 9 PM with a likelihood of not unplugging until at least 5 AM. Google provides instructions for “Adaptive Charging” to help preserve your Google device’s (Pixel 4 and newer) long-term battery life.
Samsung, with its huge selection of smartphones, also has a dedicated page to help customers manage battery life. It recommends charging regularly and maintaining battery life above 50%. While they don’t actively caution against charging overnight, they do indicate that leaving your phone connected for too long could negatively impact battery life.
Battery Saving Tips
From everything the science and the manufacturers of the most popular smartphones say, you shouldn’t let your battery drain completely. Nor can your smartphone overcharge, and that is one of the biggest takeaways. Charging your phone overnight is more of a risk to the health of the battery as much as it is a risk that the phone will suddenly combust. There are caveats to that, as anyone who puts their smartphone under their pillow at night while charging is in a different risk category. When a smartphone is under your pillow, heat gets trapped because of a lack of airflow, and that could, in very rare cases, cause a fire.
The best thing you can do is charge your phone when it reaches a certain percent. This can’t apply every time, but try and aim for something like 30% as your minimum point for charging. The number is up to you, but this will allow you to preserve your battery life longer without going through a “cycle” that will begin if you drain the battery completely. There are also other tips, like turning off notifications, certain apps that run in the background, etc., that are default warnings for preserving battery life.
Should You Charge Overnight?
Back to the question at hand of whether you should charge overnight. The primary concern is whether or not charging overnight is a danger. The answer is that it doesn’t appear to cause any major health risks. Causing a fire is more likely to happen when it’s underneath a pillow, but even that is going to be rare. There is some concern that you could do some small harm to your battery by constantly leaving it charged overnight, but again, it’s not a danger that can reduce the life by a short amount of time. We are not talking years – more like weeks or months.
Ultimately, the answer to the question of whether to charge your smartphone overnight is whatever works best for you. Can you charge your phone up to 100% before bed, or do you have time to charge in the morning? If you do, then that’s the best course of action. It really comes down to what is more convenient for you. As long as you can avoid your phone dropping to 0%, however you charge your device is likely the best thing you can do.
With all of the smart charging or quick charging available on smartphones today, there is a good chance you can get a quick boost in 30 minutes to an hour. Given that, charging overnight seems like more of a trained behavior than an absolute necessity.
The conclusion is that charging your smartphone overnight is not going to cause much issue to your phone’s battery, especially if you have a newer phone. Realistically, the manufacturers know best, so you should listen to their tips for the best way to keep your smartphone battery healthy. If, instead, you are seeing a battery drain due to a Google Play Services issue, we have the fix here.