Charging phones overnight, good or bad?

[Cyandrix]

So the world can't seem to make it's mind up from the bit Googling I did. Some say it's bad for the longevity of the battery and some say it's fine. I'd like to settle this once and for all!

[Mihle]

It's better to not do it.

But if the alternative is that the phone runs out of battery to the point where it turns off when you need it the next day, then do it.

 

Ideally you should stop charging your phone at 90% and don't let it run bellow around 20% ish if you want to optimize battery wear, but I don't bother with the above 90% thing.

 

Personally I charge my phone while I sit on my PC in the evening and unplug it when I notice it's done.

[Jimkirk363]

Ive had mobiles since the mid 90s and have always charged my mobile overnight?

[Cyandrix]

3 minutes ago, Jimkirk363 said:

Ive had mobiles since the mid 90s and have always charged my mobile overnight?

People generally change phones every 2 years, I do it every 5, so I need all the battery I can get. Did you notice any significant battery life loss?

[D13H4RD]

Once in a while, it's not going to do much harm. 

 

Everyday though, you might see some degradation a little earlier than some others. 

[Jayzer]

I used to always charge my phone overnight, and I regret it.

If I remember correctly, my last phone's battery used to drain REALLY quick, to the point where I had to get a new battery. The first charge lasted very long, but eventually the same thing happened again.

After that, I got a new phone and now I'm very cautious about its battery life.

[LIGISTX]

7 minutes ago, Cyandrix said:

People generally change phones every 2 years, I do it every 5, so I need all the battery I can get. Did you notice any significant battery life loss?

So, its impossible to ask someone that because they have nothing to compare against, no control case - unless they have two identical phones, for the entire life of both phones...

 

What we know from scientific data and released info from manufacturers is a few things:

1) batteries only can fully charge and discharge a set number of times

2) the less time your battery spends outside of about 60-80% the better

3) high wattage charge is bad when your battery is dead, most phones will charge really quick to help you get more juice quicker, this isn't good for the battery as it makes it hot)

4) heat in general is bad

 

So, with that, you have to sort of determine "where you are on the scale of care". Most new phones learn your habits and when you do plug it in to charge overnight, it will go to 80% and will only charge the rest of the way ~30-40 minutes before you typically wake up or when your alarm is set, this way you don't hurt rule number 2 - it spends less time above 80%.

 

Some phones these days come with more than a 1 amp charger which means they will charge at higher wattage, you can always just use an older wall plug that is only 1 amp, which will not allow any more than 1 watt of charging which will make the device charge slower, which is better for it as it won't heat up as much which helps both 3 and 4. My iphone Xs for example can charge "faster ish" than 5 watts (5v 1 amp), but i typically use an old iphone wall plug anyways since i usually don't need it to charge fast since I let it charge over night. IF I am in a situation where I need more juice quick, yea I will throw it on my 20 watt charger and let it suck as much power down as it can.

 

All of this is somewhat relative and subjective. Thats why you need to determine your level of cares. Even if you use the charger that came with the phone and it is higher than 1 amp, its not going to just magically kill it. Yes, if you only use that charger, it may make it degrade a bit faster than a 5 watt charger, but its not the end of the world. If you charge it every night, and your phone doesn't have the option to "smart charge" and not go to 100% until before you wake up, its not going to kill it. But if you try and just manage things, and if your phone is at 40% and your around a charger, go ahead and charge it up till like 75% then go about the rest of your day, but maybe don't sit there and stress about "oh gosh its at 55% should i top it up right now?!?". Don't let it be a serious concern, and just do things to help the 4 things that hurt the battery. Also, don't forget, you can always have the battery replaced :). I plan to keep my Xs a while, and once the battery starts to go, I will likely walk into an apple store, pay them the somewhat ridiculous amount, and have them change the battery out - or sell it and buy a new one, lol. 

[LIGISTX]

1 minute ago, Jayzer said:

I used to always charge my phone overnight, and I regret it.

If I remember correctly, my last phone's battery used to drain REALLY quick, to the point where I had to get a new battery. The first charge lasted very long, but eventually the same thing happened again.

After that, I got a new phone and now I'm very cautious about its battery life.

There are a lot of factors that play into battery degradation... Also battery quality is a large factor. Its not really something I would let bug you, just use the device in a way that isn't going to interrupt your day, and be cognizant of the things I mentioned in the post above

[Jayzer]

2 minutes ago, LIGISTX said:

There are a lot of factors that play into battery degradation... Also battery quality is a large factor. Its not really something I would let bug you, just use the device in a way that isn't going to interrupt your day, and be cognizant of the things I mentioned in the post above

Well thank goodness I don't use that phone anymore.

Also for some reason, even when I wasn't using it AT ALL, it'd heat up while in my pocket.

thank god I got a new phone

[jynx_Moondoggie]

23 minutes ago, Cyandrix said:

People generally change phones every 2 years, I do it every 5, so I need all the battery I can get. Did you notice any significant battery life loss?

 I was big brain a few years ago, and had my iPhone 6s hooked up to my portable charger all day every day, charging both at night. That phone now has like no battery life and I am now much more careful with my newer model's battery

 

[LIGISTX]

2 minutes ago, Jayzer said:

Well thank goodness I don't use that phone anymore.

Also for some reason, even when I wasn't using it AT ALL, it'd heat up while in my pocket.

thank god I got a new phone

That sounds like older android problems. Glad you got a newer phone.

[Jayzer]

1 minute ago, LIGISTX said:

That sounds like older android problems.

 

It was a Samsung Galaxy S5. I think I've had it since 2018, and it was being used before that as well, so it probably makes sense why it constantly did that.

2 minutes ago, LIGISTX said:

Glad you got a newer phone.

So am I 

[LIGISTX]

Also.... just to throw this out there. I still have my ipohne 3G, I charged it every night for years, and literally only stopped using it as an alarm clock last year. Battery is still totally fine. I used a 4s for YEARS, and then MANY MORE YEARS as a dedicated "ipod" in my car. Its battery was fine, it was in airplane mode, on 24/7/265 and I only had to charge it when it was working as an ipod maybe once every other week (again, after charging it every night for years, and using it like any college kid would, which was a lot). Both of those phones had 0 smart charging features, and were much older battery tech. Seriously, the iphone 3g still holds a charge for weeks as an alarm clock. I think the 4s battery finally died because the battery was 0% for years after I stopped using it and forgot about it in my drawer :/.

 

So, again, not just one thing is going to kill it. Just be smart about it, try and manage its charge, and don't super worry. 

[LIGISTX]

1 minute ago, Jayzer said:

It was a Samsung Galaxy S5. I think I've had it since 2018, and it was being used before that as well, so it probably makes sense why it constantly did that.

Older android was much less good about halting process and being smart about managing what the software was doing. One reason I used to like iphone much more. These days, android is almost as good as iphone in this regard, miles better then they used to be.

[Beerzerker]

It's best to allow a battery to fully discharge before recharging.

This what I've always done with mine and I even have an old phone I still use as an alarm clock that's at least 8 years old with it's original battery that still holds a fairly good charge, lasting for about 4-5 days at least even now.

What happens to a battery is it "wants" to only charge up to a cretain point if you short-cycle the periods between charge and discharge. By doing this the battery will build resistance to being fully charged to capacity and it then starts to die more quickly between charges. 
It's absolutely suggested to discharge a battery to at least it having 20% or less of it's charge left before recharging but you can just let it die period if you want and it's helpful if you do that on occasion.
This way the battery will last longer, probrably be useable for the expected life of the phone (As long as you'd be using it) and still be good enough it's not a real hassle to deal with along the way.

BTW for things like cordless drills and so on, the same applies because those batteries are essentially the same thing and of course, work the same way.
Believe it or not I had one of my former employers show me a trick about this. He explained it as the battery developing what he called a "Memory" and to "Break" the memory he'd take the cordless drill, popped in in the freezer (Overnight) in a ziplock bag making sure the chuck end didn't touch the bag itself while it turned and he had tied the trigger so it was just running until it absolutely died while in the freezer.
The next morning he'd then remove it, let it all warm up again while still in the bag, take the battery out of the drill and then charge it - The "Memory" was broken and it would then recharge to full capacity again.
I don't really understand how it works but it does - I saw him do it and he proved (At least with those batteries) it works.

[mariushm]

The charger built inside your phone SHOULD be smart enough to stop charging the battery once its filled. They usually are. So leaving the phone plugged in should actually help instead of cause bad things ... the phone should be powered from the DC in while the battery sits there doing nothing... with the phone disconnected, it would be powered from battery so battery would be discharged and therefore you'd have to charge it sooner.

 

Disconnecting the cable when the phone says it's done charging vs leaving it overnight results in pretty much the same thing - the battery is 100% full.  If you're aiming to reduce "stress" on the battery by not having it over charged, then you failed in both instances, battery hit 100% in both cases. 

 

If you want to extend the life of a battery, you would aim to stop charging at around 95-98% and you'd start charging at around 20-30% 

There's different chemical formulations and charging patterns. 

Ni-Mh batteries preferred to be fully discharged and then charged to the max, otherwise you'd get a sort of "memory effect" 

Lithium-Ion and Lithium-Polymer don't have a memory effect and they care about being too discharged, but there's a protection chip inside the battery pack preventing you or the phone from discharging them too much, so it's pretty much fool proof. 

 

You can extend the life of a battery by a bit by not charging it all the way - some phones already do that, stopping at let's say 4.18v instead of 4.22v or whatever the peak voltage is. 

 

But best you can probably do to extend the life of your battery is to CHARGE IT SLOWLY.  For example, instead of using a 1-2 A charger to charge your battery in 15-30 minutes, use a 0.5A charger and let the battery charge for 1-2 hours. 

You can probably increase the battery life by 20-50% (more charge-discharge cycles) by reducing the wear and tear caused by heat and high currents during fast charging.

 

 

 

[NineEyeRon]

The mixed advice comes from the fact the tech has changed so much over the last few years. Also with so many new and older and different battery tech devices needing different things it becomes even more confusing.

 

Ideally software should take care of the battery, you just plug it in or put it on a charger when convenient and the device decides how it charges. This is starting to come in now which will just change the rules again.

 

My approach is to just not worry and charge when it needs it or is most convenient. My iPhone 7 still works as a daily driver despite running known battery killer apps, I bought it new many years ago.

[Moonzy]

1 hour ago, Beerzerker said:

What happens to a battery is it "wants" to only charge up to a cretain point if you short-cycle the periods between charge and discharge. By doing this the battery will build resistance to being fully charged to capacity and it then starts to die more quickly between charges. 

I think this is only for NiMH batteries or something, li-ion doesn't care as far as I know

 

https://en.m.wikipedia.org/wiki/Memory_effect

 

Fully discharging li-ion would actually damage it especially if the battery management system sucks

 

For li-ion, 20-80% is the best charge to be at from what I read

[D13H4RD]

58 minutes ago, Beerzerker said:

It's absolutely suggested to discharge a battery to at least it having 20% or less of it's charge left before recharging but you can just let it die period if you want and it's helpful if you do that on occasion.

Bad idea especially on lithium-based batteries where they do not like being used up until they are starved of a charge.

 

The “memory effect” was true for NiMH batteries, but that doesn’t apply to lithium-based batteries.

[Beerzerker]

Good to know all that, I can only relay what I've had happen with mine but that's how it's been (So far).
The term for discharging it too much is called "Deep Discharge" and it can hurt certain battery types like an older lead acid battery for example.

The universal standard for "When" to recharge from what I was taught is when it gets to about 20% capacity left in it. That was shown to me in a class put on by a rep from Exide battery, I used to work on battery powered lift equipment and maintenance of the batteries they used was part of the work I had to do, hence the class.
Things have changed since that time but the "20% is when to recharge" standard to my knowledge hasn't changed regardless of battery type and is still in use today overall.

I understand different battery types will respond differently, that's just how it is. Thing I could suggest is if you don't know what battery type your device has in it, find out and go by whatever guidelines exists for it.

[Jimkirk363]

3 hours ago, Cyandrix said:

People generally change phones every 2 years, I do it every 5, so I need all the battery I can get. Did you notice any significant battery life loss?

didnt notice any no especially on the old Nokias.

[LogicalDrm]

-> Moved to Phones and Tablets

***

 

Whats the reasoning someone uses to say charging overnight is not recommended? Overcharge? That issue would be present on day time too, so thats not valid reason. Besides that, modern hardware will stop loading when battery is full, then resume if charge drops under 90%.

 

Its more dangerous to keep charger constantly plugged in because of overheating risk. And yet we all do it all the time.

[Commodus]

Keep in mind that at least some phones (including iPhones) have intelligent charging management that limits the amount of time your device spends fully charged. You can leave it plugged in (or on a pad) and it won't venture beyond a certain capacity until you're likely to need it. In other words, there's not much point to unplugging as long as the feature is enabled.