Should you let your phone charge overnight?

Your body refreshes itself at night as it prepares for a full day ahead. So why shouldn't your smartphone battery get the same treatment? Now, when you are fast asleep dreaming about the 2018 flagships, the cell inside your phone will charge for the two hours or so that it takes to get back to full strength. For the rest of the night, software will stop the charging process once the battery is back to 100%. This prevents damage that could be done to the battery by overcharging. But it doesn't prevent the battery from generating heat.

If you keep your phone under your pillow or blanket, or even inside a case at night while charging, you could be limiting the ability of your battery to charge up to full capacity. For example, if your battery hits a temperature of 104 degrees Fahrenheit for a year, you will only recover 65% of the battery's capacity when you charge to 100%. Even more amazing, if your battery is running at 140 degrees Fahrenheit for just three months, the cell will lose 40% of its capacity.

The data shows that keeping your battery charged between 40% and 80% will allow it to have an optimal life, which suggests that a mid-afternoon power snack is a good thing for your phone's power cell. Charging overnight will not allow you to monitor this (unless you get up to pee every hour). So if you are going to let your phone charge up all night, make sure that it isn't covered by anything that would make the battery heat up unnecessarily, including a case.

source: BatteryUniversity



1. TechNeck

Posts: 656; Member since: Aug 29, 2014

I don't really charge my phones overnight because of this. Right now I'm using my old V20 just for the removable batteries when I'm on the go.

27. buccob

Posts: 2975; Member since: Jun 19, 2012

Recent Xperia devices provide a feture called Battery Care which learns your night time routines and then performs charging accordingly... It basically do a slow charge and it stops at 90% and then it will resume charging 30 minutes before your next alarm (or the time you usually unplug, whichever comes first).... And over a year with my Xperia XZ leaving it to charge over night up to 100% my battery life is currently at 98% of its original capacity (checked under service tests)... After experiencing this, I have truly appreciated the feature and would love to upgrade to phone that have something like this.

2. rouyal

Posts: 1583; Member since: Jan 05, 2018

I charge overnight. I don’t want to babysit the phone battery by spot charging during the day. One less thing for me to worry about.

7. lyndon420

Posts: 6824; Member since: Jul 11, 2012

We definitely need new battery tech. I leave my Nexus 6 on the tylt wireless charger overnight, but now after 3 or so years my phone is starting to randomly shut down even right after taking it off the charger (but usually only when at work which is peculiar - battery says it's 97 or 98%). Damn...sure miss the good old days when you could change the battery in your phone as easily as ones in your flashlight.

23. Sparkxster

Posts: 1240; Member since: Mar 31, 2017

Graphene batteries should be coming soon there are already powerbanks with them in it and also solid state batteries which are a few years off.

36. VZWuser76

Posts: 4974; Member since: Mar 04, 2010

I think in this case it's less about new battery tech and more with new charging tech, or rather software. They could have something like the old Moto Actions, where you set a start/stop time for charging. If you plug in your device during that period, it will say charge up to 80%, then stop charging down to 50%, then charge to 80%, rinse and repeat. Then when it gets close to the end of the specified time, it will start charging to 100%. Consider it a smart or battery saving charging process. Something else to consider is the types of charging we have now. These fast, rapid, and dash charging setups will heat up the battery more than the older slow charging methods. Wireless/induction charging also generates more heat than the older slow charging, simply due to the induction process. Maybe they could simply allow you to choose a slower/lower output charging mode so it wouldn't affect the batteries as much charging overnight. Make it so it would take 6hrs to fully charge a dead battery, which shouldn't heat up the battery much. Just some thoughts.

3. NarutoKage14

Posts: 1327; Member since: Aug 31, 2016

So according to this, heat is the primary factor in battery degradation. Good to know.

4. BGChicago

Posts: 225; Member since: Nov 16, 2014

So quick charges are probably very bad. I have a "special" cable/power brick that takes about 6 hrs to recharge. That's what I use overnight.

5. torr310

Posts: 1676; Member since: Oct 27, 2011

Avoid fast charger is the way to go.

8. Sparkxster

Posts: 1240; Member since: Mar 31, 2017

I wirelessly charge my phone overnight. Takes longer than fast charging but it's better on the battery.

12. torr310

Posts: 1676; Member since: Oct 27, 2011

I tried wireless charge with Galaxy S7 before and it run hotter than wire. So I haven't used the wireless charger since then.

34. Rigmaster

Posts: 234; Member since: Jan 22, 2018

I think wireless chargers have their own heat dissipation issues. Just recently saw a YT vid on heat and wireless charging. Different path - same problem. Better battery tech definitely needed for all of us.

9. adibuyono

Posts: 50; Member since: Mar 29, 2017

Suddenly feel so glad with Qnovo tech in my Xperia XZ Premium..

11. redmd

Posts: 1943; Member since: Oct 26, 2011

Answer: you may charge your phone overnight, just don't let it generate heat to avoid battery degradation.

14. medtxa

Posts: 1655; Member since: Jun 02, 2014

Yeah? Keep alarm at midnight so your phone doesn't overcharge then.

15. MaryPoopins

Posts: 324; Member since: Jan 15, 2015

"If you keep your phone under your pillow or blanket, or even inside a case at night while charging," Is this actually a thing? Are people* keeping the phones all snuggly and wrapped up warm while charging? *idiots

17. Sania

Posts: 97; Member since: Nov 04, 2017

I always charge overnight with my turtle 1amp charger

18. TheOracle1

Posts: 2337; Member since: May 04, 2015

I've always charged overnight and never had an issue. Taking my phone off the charger 5his morning fully charged they were at normal temperature.

19. hansip87

Posts: 228; Member since: Nov 10, 2015

Qnovo and Battery care inside Xperia should be the benchmark, pity that big names don't seem interested in improving the battery charging environment quality like Sony does.

20. Feanor

Posts: 1389; Member since: Jun 20, 2012

Well, tell that to those crying that Sony is obsolete and should give up business; Waterproofing, anyone? Digital Noise Cancellation? Adaptive overnight battery charging? Super slow motion video? HDR 4K recording? Next time you enjoy one of these features in your Samsung, thank Sony for bringing them first.

21. peace247 unregistered charging my phone's battery overnight for the last 2 years($100 redmi 2 btw) and the battery is still going strong.....

22. NewroticSlob

Posts: 182; Member since: May 09, 2013

Smart chargers... they work. Been using one with any charger on my Note 8. Still at 102% health from what AccuBattery says and have had my Note since launch.

24. Loubielou

Posts: 603; Member since: Jul 11, 2012

People do not seem to realise that over charging there phone battery makes it drain faster after they have left it running all night,so instead of making your phone last longer it will have shorter running time,that is why I use battery alert to tell me when my battery is Full and unplug the charger and the batterylife on my S8 plus is lasting more than a day

35. rouyal

Posts: 1583; Member since: Jan 05, 2018

Hate to break it to you, but a phone knows when it’s done charging and stops itself. If the phone overcharged itself, the battery would explode. No need for an app, no need to unplug

26. WingMan

Posts: 263; Member since: Mar 28, 2008

The graphics is about battery storage not battery usage. It will show you how much capacity the battery will lose after 1 year stored at the following temps when left at 40 and 100% charge respectively. it is about battery STORAGE, not usage.

29. shnibz

Posts: 510; Member since: Sep 18, 2011

I used to always charge overnight. The Huawei Mate 9 has cured me of that though.

30. hansip87

Posts: 228; Member since: Nov 10, 2015

what people really need to do for charging issue is to buy a simple electric timer that will charge the device at night for max of 3 hours and then the problem is solved..

31. p51d007

Posts: 705; Member since: Nov 24, 2013

I NEVER charge my phone over night, or any rechargeable battery. They obviously are suppose to stop charging when full, but there have been many stories of phones catching on fire. Inside the charging circuit it is suppose to stop the charge. If that fails, the battery will overheat. At some point, the thermal fuse inside the battery is suppose to open (melt) to break the connection. If that fails, then the battery could potentially catch fire. It's not a risk, I am willing to take.

33. tokuzumi

Posts: 1929; Member since: Aug 27, 2009

Quick Charging kills the battery as well. My HTC 10 will die when it reaches 33%. There were times where I'd be using Quick Charge, and the phone would be hot to the touch. I don't even use the Dash Charger on my OnePlus 3T. 2 amp charging is sufficient for overnight charging. Plus it doesn't put as much heat into the battery.

37. tempdogg74

Posts: 136; Member since: Jan 04, 2009

I charge my phone before bed.Take off charging pad. Put in low power mode over night still have 99 or 98 percent when I wake up for work in the morning. The Magnificent Note 8. No need to charge overnight.

* Some comments have been hidden, because they don't meet the discussions rules.

Latest Stories

This copy is for your personal, non-commercial use only. You can order presentation-ready copies for distribution to your colleagues, clients or customers at or use the Reprints & Permissions tool that appears at the bottom of each web page. Visit for samples and additional information.