Is it true - charge for an iphone is between 21% and 79%

FatPuppy

macrumors 68000
Original poster
Jul 14, 2012
1,707
140
That the best charge for an iphone is between 21% and 79% ? And for tablets 11% and 79%?
 
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FatPuppy

macrumors 68000
Original poster
Jul 14, 2012
1,707
140
Where have you heard this and why?
Many people said that it is not recommended to let the iphone run below 20% and that is not recommended to charge the iphone while it is on 80% or higher.
 

MacDawg

macrumors Core
Mar 20, 2004
19,708
4,274
"Between the Hedges"
Many people said that it is not recommended to let the iphone run below 20% and that is not recommended to charge the iphone while it is on 80% or higher.
Not sure who "many people" are, but that is likely just tribal knowledge and speculation

I charge when I need it or when it is available and don't worry about it
 

zorinlynx

macrumors 603
May 31, 2007
5,548
6,514
Florida, USA
Stop worrying about it. It's a phone. The battery is cheap. You're only going to have it 2-3 years.

It's true that a full charge can cause the battery to age faster than a 80% charge. This is used in electric cars like the Tesla to prolong battery life; you only charge it up to 80% unless you're going on a long trip... However, this is a car with a battery worth many $thousands.

It's not worth worrying about it for a phone.
 

Tyler23

macrumors 603
Dec 2, 2010
5,641
146
Atlanta, GA
That the best charge for an iphone is between 21% and 79% ? And for tablets 11% and 79%?
No, this is not true. Charge the device to 100%, and use normally. Charge when you need to and there is no issue charging up to 100% or letting it drop down to a few percent.
 

sunking101

macrumors 604
Sep 19, 2013
6,671
1,812
New batteries cost $10-20 and never generally need replacing for 18+ months even for a heavy user who charges twice per day. Just use the phone and charge when necessary. These things don't hold charge for anywhere near long enough, so the suggestion of only charging them to 80% of capacity is daft.
 

I7guy

macrumors Core
Nov 30, 2013
20,457
8,282
Gotta be in it to win it
For any phone in general charge as much as you want and don't worry about. The battery will outlast you. When I can I keep mine on the charger. Others that I know with a note 3 and s5 do as well.
 

gnasher729

macrumors P6
Nov 25, 2005
16,509
3,102
For any phone in general charge as much as you want and don't worry about. The battery will outlast you. When I can I keep mine on the charger. Others that I know with a note 3 and s5 do as well.
I most definitely hope that my phone battery will not outlast me!

Many people said that it is not recommended to let the iphone run below 20% and that is not recommended to charge the iphone while it is on 80% or higher.
I'd say that's nonsense. It doesn't make any sense at all. The charging and the percentage display are under control of the iPhone and Apple's software.

When the phone displays "80%", you are at a point where Apple decided that it can do with more charge - if charging more would cause damage, the phone would display "100%" and would have stopped charging already. When the phone displays "100%", that's the point where Apple thinks charging more isn't useful - the phone isn't absolutely fully charged, but there are people who won't leave with their phone until it displays that it's 100% charged, so Apple allows these people to unplug their phone and leave their home earlier. At 100% display, it's still charging (very slowly) up to the point where it would be bad for the phone and then it stops charging.

Remember you don't see how far the phone is charged, you see what Apple wants you to see. Displaying 80% when charging more would cause damage would be idiotic.
 
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t76turbo

macrumors regular
Sep 20, 2012
193
240
I would suggest you read some material on batteryuniversity.com. On their home page, their 'Most Popular Articles' section has a number of things specific to charging and prolonging the life of Li-ion batteries.

The principals of charging li-ion batteries are universal. Apple has no super special handle on the process. Although if they give guidelines for their products, it is probably worth heeding.

I try to let my iphones, ipads, and ipods drop to at least 20% before I charge. I may have topped off a device once or twice from an already charged state of 80% or higher. But I try to avoid that. Both of my iphone 5's, my ipad 3 and ipad air still go multiple days without having to recharge and charge back up pretty quickly. So I assume my batteries are in good shape still.
 

I7guy

macrumors Core
Nov 30, 2013
20,457
8,282
Gotta be in it to win it
I would suggest you read some material on batteryuniversity.com. On their home page, their 'Most Popular Articles' section has a number of things specific to charging and prolonging the life of Li-ion batteries.

The principals of charging li-ion batteries are universal. Apple has no super special handle on the process. Although if they give guidelines for their products, it is probably worth heeding.

I try to let my iphones, ipads, and ipods drop to at least 20% before I charge. I may have topped off a device once or twice from an already charged state of 80% or higher. But I try to avoid that. Both of my iphone 5's, my ipad 3 and ipad air still go multiple days without having to recharge and charge back up pretty quickly. So I assume my batteries are in good shape still.
It is not worth any of my time to try and maximize battery longevity. Others may feel the same way: I don't know. My time is more valuable than the amount charged for a replacement.
 

joeblow7777

macrumors 603
Sep 7, 2010
5,968
6,757
There are still a lot of misconceptions based on old battery technology. Modern lithium ion batteries can be safely charged and discharge at and to any percentage, and are kept from overcharging so there's no harm in leaving them plugged in overnight. It is however true that they should not be allowed to TOTALLY discharge, but any device that uses such a battery will automatically shut down before that happens, so it's fine to use it right up to that point.
 

Newtons Apple

Suspended
Mar 12, 2014
22,764
14,918
Jacksonville, Florida
Many people said that it is not recommended to let the iphone run below 20% and that is not recommended to charge the iphone while it is on 80% or higher.
Just plug your phone in when you sleep and do not worry about it.

Depending on how much you use your iPad, just charge it when you want.

There is little you can do to greatly increase or decrease your battery performance in either. Just use them and enjoy!

You got to have other things to worry about, if not I am jealous!
 

eelw

macrumors 6502a
Sep 19, 2012
630
26
If you're referring to charging efficiency, then sure. Anything below 80%, charging is done at full current charge. Between 81-95%, slower charging rate. 95 and above, it's a trickle charge to remain topped off.
 

sunking101

macrumors 604
Sep 19, 2013
6,671
1,812
It is not worth any of my time to try and maximize battery longevity. Others may feel the same way: I don't know. My time is more valuable than the amount charged for a replacement.
Agreed. Not being able to use your $800+ device properly because you're fretting about the $20 battery is ridiculous. What's the WORST that can possibly happen? Aw no, a replacement in 18 months.
 

I7guy

macrumors Core
Nov 30, 2013
20,457
8,282
Gotta be in it to win it
Agreed. Not being able to use your $800+ device properly because you're fretting about the $20 battery is ridiculous. What's the WORST that can possibly happen? Aw no, a replacement in 18 months.
That is exactly correct. Not being able to use your [insert MSRP here] device because you're a slave to the battery charging routine is lunacy.
 

cynics

macrumors G4
Jan 8, 2012
11,313
1,696
There is some science to helping a lithium based battery have a longer life span.



There is nothing new to the technology and even though it's in a iPhone the same physics and chemistry apply to all lithium based batteries.

I really wouldn't worry about it though. The difference it makes is to insignificant to worry about. Be better to charge your phone in cooler areas then worrying about how depleted it is.
 

PNutts

macrumors 601
Jul 24, 2008
4,835
336
Pacific Northwest, US
Any advice other than "charge it when you want for as long as you want" is wrong. There are no thresholds (high or low) to worry about. Unfortunately Apple changed their battery information pages again and removed even more information.
 

mtneer

macrumors 68030
Sep 15, 2012
2,756
1,780
That the best charge for an iphone is between 21% and 79% ? And for tablets 11% and 79%?
The best charge for anything is at 100%. I don't understand why anything less than at would be better (or best)?? :confused:
 

androiphone

macrumors 65816
Dec 13, 2009
1,000
1
OP just watch this: https://www.youtube.com/watch?v=LBKuOomv9Ko and then just use your device like normal.

The main point I will point out is that yes it is not good to let a battery go completely flat but modern devices have built in protection for that and that's why they turn off at low battery, when it says 0% the actual battery still has a little left in it but it turn off to protect itself.
 

sunking101

macrumors 604
Sep 19, 2013
6,671
1,812
OP just watch this: https://www.youtube.com/watch?v=LBKuOomv9Ko and then just use your device like normal.

The main point I will point out is that yes it is not good to let a battery go completely flat but modern devices have built in protection for that and that's why they turn off at low battery, when it says 0% the actual battery still has a little left in it but it turn off to protect itself.
Exactly. There are systems in place so that we don't have to worry about these things. It's a mobile phone for goodness sake, we WILL be caught out now and again with a fully flat battery. It's nothing to be concerned with.