Charging your phone overnight feels like the most convenient thing in the world. You wake up to a phone that’s ready for the day. But that convenience actually comes at a cost, and that’s faster battery degradation.
Thankfully, it doesn’t have to be this way. Android has a feature called Adaptive Charging that can reduce damage without taking away the convenience of waking up to a fully charged phone.
Leaving your phone’s battery at 100% isn’t ideal
Overnight charging is costing you battery health
Most smartphones come with lithium-ion batteries, and they don’t like being full. The moment your phone hits 100%, the cells hit their highest possible voltage, and that’s where chemical degradation happens fastest. The internal components stay under constant pressure as long as the battery stays in that state. In fact, the stress starts kicking in the moment your phone goes past 80%, which is why the battery protection feature on Android pauses charging after 80% by default.
The same thing also happens on the other end too. Once the battery drops below 20%, it’s under a different kind of stress, and that’s just as bad for long-term health, which is where the 20-80 battery rule comes from. You should keep your battery between roughly 20% and 80% rather than running it from empty to full every single time.
And that’s exactly the problem with overnight charging. When you plug in at night, the phone hits 100% within the first couple of hours. Then it just sits there, fully charged, for the rest of your sleep. Although modern-day batteries have gotten better at handling occasional full charges, doing this regularly for months can take a toll on the battery health. It can deteriorate your phones’ battery 10 to 15% faster, which is not a lot, but not something you should totally ignore — especially if you’re planning to keep it for years.
Adaptive charging can make overnight charging easier on your battery
Let your phone time its own charging
Adaptive charging is a built-in feature that helps with the exact problem we just talked about. When you plug in your phone overnight, it charges it to 80% at the usual speed. After that, it slows down or holds the charge before reaching 100%. It times this in a way to finish a full charge a few minutes before you typically wake up or your alarm goes off. This gives you the best of both worlds — your phone is fully charged when you wake up, but it isn’t sitting at 100% for hours on end while you sleep.
Every manufacturer has its own name for this, but they all do the same thing. Google calls it Adaptive Charging, Samsung calls it Sleep time protection and Motorola labels this Optimized charging.
On a Pixel, you can head to Settings > Battery > Battery health > Charging optimization and turn on Use charging optimization. Then, choose Adaptive Charging. If you have a Samsung phone, go to Settings > Battery > Battery protection and turn on Sleep time protection. If you don’t see it, make sure you’ve selected the Basic option. On Motorola, head to Settings > Battery > Battery protection and turn it on. Some Motorola phones give you a bit more control here, letting you choose between Smart schedule, which handles everything automatically, or Manual schedule, where you set the charging window yourself.
This feature won’t work right away. Your phone initially needs some time — usually a couple of weeks — to learn your charging habits and sleep schedule. If either of those is irregular, the feature won’t work as expected. The good thing is that you don’t need to worry about this interfering with charging speeds during the day.
There’s one more setting you should turn off for charging overnight
Skip fast charging while you sleep
Fast charging is great most of the time. But higher charging speeds mean higher heat and higher stress on the cells, and heat is one of the fastest ways to age a lithium-ion battery. This is especially a concern if you’re using one of those wireless charging stands to charge your phone overnight, since wireless charging already runs hotter than a cable to begin with.
Charging speed is obviously not a priority when it comes to overnight charging. So, turning off fast charging is another thing you can do to protect the battery while charging overnight. You don’t have to do this manually, though. You can set up an automation that disables fast charging at, say, 10PM and turns it back on when you wake up.
Not every Android phone allows you to disable fast charging, though. But if yours does, it’s definitely worth trying out. If you have a Galaxy phone, this is easy to pull off with the Routines feature.
