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MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
I'm using an iPhone 13, and my phone typically has 20% battery left, which I'll be charging.

I have seen some sayings that you should charge your iPhone with 40%-50% remaining power. This is the most friendly way to the battery of the mobile phone and can better protect the battery of the phone. Is this believable?

I want to discuss this with you guys. So how much power do you have left on your iPhone when you charge it?

In addition, does charging for a long time have an impact on the iPhone battery? Like charging it all night.
 

barkomatic

macrumors 601
Aug 8, 2008
4,424
2,627
Manhattan
I charge my iPhone every night regardless of its remaining power--unless it's already at 100%. I certainly don't set an alarm to wake me up in the middle of the night to unplug my iPhone so it stays plugged in all night and I haven't had any issues.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
I charge my iPhone every night regardless of its remaining power--unless it's already at 100%. I certainly don't set an alarm to wake me up in the middle of the night to unplug my iPhone so it stays plugged in all night and I haven't had any issues.
Setting an alarm in the middle of the night to unplug the charging cable seems like an absurd act lol:D. I also sometimes charge my iPhone overnight but less often, I usually charge during the day, or when my iPhone is running low on battery.
 
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Atomic1977

macrumors 6502
Jul 8, 2017
320
137
West Bend Wisconsin
As Far as I know leaving a phone or a device plugged in to charge should not cause harm. I would not keep it plugged in once it’s charged all the way though for very long.
 

Splitrail

macrumors 6502a
Dec 26, 2021
514
628
I'm using an iPhone 13, and my phone typically has 20% battery left, which I'll be charging.

I have seen some sayings that you should charge your iPhone with 40%-50% remaining power. This is the most friendly way to the battery of the mobile phone and can better protect the battery of the phone. Is this believable?

I want to discuss this with you guys. So how much power do you have left on your iPhone when you charge it?

In addition, does charging for a long time have an impact on the iPhone battery? Like charging it all night.
..................again & again................the topic some are delighted to be a part of, and those that maintain it doesn't make a hill of beans what you decide to do.
OK, here you go............
iPhone 13 Pro.....
charge every morning @ ~ 15% of 50%.
disconnect at 95-100%, usually ~ 3 hours.
20W Apple Charger and OEM "C" to Lightning Cable that came with the phone.
After one year, for what it's worth, battery health is at 100%.
Now What?
 
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Shirasaki

macrumors G5
May 16, 2015
13,893
8,444
Charge whenever i like and whenever i need. Full stop. No time to stress this kind of stuff and definitely not worth setting up alarm to. If that $79 really can stress you out that much, I’d rethink what I am doing if i were you.

Better battery tech is what pushes less and less frequent charging, not babysitting it like a newborn.

With that being said, if you don’t use your device for extended period (3 mo Or longer), keeping charge level at around 40% and recharge once in a while will help prolonging the battery life.
 
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Mark Stone

macrumors demi-god
Mar 20, 2022
416
442
In its case.
I'm using an iPhone 13, and my phone typically has 20% battery left, which I'll be charging.

I have seen some sayings that you should charge your iPhone with 40%-50% remaining power. This is the most friendly way to the battery of the mobile phone and can better protect the battery of the phone. Is this believable?

I want to discuss this with you guys. So how much power do you have left on your iPhone when you charge it?

In addition, does charging for a long time have an impact on the iPhone battery? Like charging it all night.
Charging the battery on a modern smartphone is too frequently overthought. On your 13, go to Settings>Battery>Battery Health & Charging and make sure that the “Optimized Battery Charging” is switched on. Then charge your 13 whenever you feel like it, regardless of the battery percentage.
 
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MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
As Far as I know leaving a phone or a device plugged in to charge should not cause harm. I would not keep it plugged in once it’s charged all the way though for very long.
So I think you should rarely charge your phone while sleeping.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
..................again & again................the topic some are delighted to be a part of, and those that maintain it doesn't make a hill of beans what you decide to do.
OK, here you go............
iPhone 13 Pro.....
charge every morning @ ~ 15% of 50%.
disconnect at 95-100%, usually ~ 3 hours.
20W Apple Charger and OEM "C" to Lightning Cable that came with the phone.
After one year, for what it's worth, battery health is at 100%.
Now What?
Your phone battery is in good shape, congratulations bro.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
Charge whenever i like and whenever i need. Full stop. No time to stress this kind of stuff and definitely not worth setting up alarm to. If that $79 really can stress you out that much, I’d rethink what I am doing if i were you.

Better battery tech is what pushes less and less frequent charging, not babysitting it like a newborn.

With that being said, if you don’t use your device for extended period (3 mo Or longer), keeping charge level at around 40% and recharge once in a while will help prolonging the battery life.
Charging anytime, anywhere to keep the battery fully charged is how most people deal with it:D. But thank you for your suggestion.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
Charging the battery on a modern smartphone is too frequently overthought. On your 13, go to Settings>Battery>Battery Health & Charging and make sure that the “Optimized Battery Charging” is switched on. Then charge your 13 whenever you feel like it, regardless of the battery percentage.
I have "optimized battery charging" turned on, thank you very much for such detailed instructions.
 
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RRC

macrumors 6502a
Nov 3, 2020
836
1,293
Mine gets fully charged every night regardless of how much is left or how much I've used. If it needs a top up during the day I'll use my magsafe charger for a bit, but overnight it's only ever plugged into the slow 5w apple charger. Never had any battery issues with any iPhone doing it this way.

Too many things in life to worry about without adding a phone battery into the stress mix lol 😂
 
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Splitrail

macrumors 6502a
Dec 26, 2021
514
628
..................again & again................the topic some are delighted to be a part of, and those that maintain it doesn't make a hill of beans what you decide to do.
OK, here you go............
iPhone 13 Pro.....
charge every morning @ ~ 15% of 50%.
disconnect at 95-100%, usually ~ 3 hours.
20W Apple Charger and OEM "C" to Lightning Cable that came with the phone.
After one year, for what it's worth, battery health is at 100%.
Now What?
FWIW update.................This morning I put the phone on charge at 49%. After 2 hours it's up to 98%.
 

reppans

macrumors regular
Dec 2, 2006
235
125
Credible/corroborating research (eg link1 and link2) all seem to say the same thing - avoid high states of charge (SoC) for longest service life. I personally like the ‘charge only what you need, and when you need it’ approach.

Low low SoC appears stress-free/fine for daily use devices (per the research links). IMHO, the ‘keep it above 40%’ comes from long-term storage advice where self-discharge eventually risks the batt falling below critical minimums. That’s not an issue for daily use devices.

With today’s automation options (smartplug/shortcuts and USB dongles), after one-time set-up, it’s now inexpensive/effortless to program custom charge optimizations where you can plug-in once/day and forget it, just like everyone else. Of course, this is assuming your usage pattern is suitable. I personally wouldn’t bother to plug-in a second time per day just to save battery, but if I’m going to plug-in once/day anyway, then why not use a better charge optimization to preserve batt?

Does it work? I’ve recently run battery meter recalibrations/full rundown tests on my 3yo iPhoneXR and previous 10yo iPhone5 and am currently running the test on my 11yo iPad2 streaming YT movies (what it looks like so far). FWIW the older devices were generally cycled 80-20 (plus 3yrs in storage), while I’ve shifted the XR from 75-25 down to 65-15, based on above research. The XR has seen 8% SoC way more than 80%.

(What can I say… I’m a battery/efficiency hobbyist and just like testing this stuff…. for ‘science’)

EDIT: iPad2 lasted 8hrs, running a consistent 10%/hour, but died still indicating ~20% remaining batt.
 
Last edited:

now i see it

macrumors G3
Jan 2, 2002
9,698
19,442
This is the general rule for lithium ion batteries though not specifically iPhone batteries.
iPhone batteries likely aren’t capable of the cycles stated below but the trend will be the same: the farther the iPhone battery gets discharged, the more stress it puts on the battery

"You can do over 40,000 charge/discharge cycles when going from 30% to 70% only.
Or over 35,000 charge/discharge cycles from 20% to 80%;
28,000 cycles from 10% to 90%;
15,000 cycles from 8% to 92%,
7,500 cylces from 6% to 94%,
and the capacity reduction goes faster and faster, finally reaching 500 cycles when recharging from 0% to 100%."
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
Mine gets fully charged every night regardless of how much is left or how much I've used. If it needs a top up during the day I'll use my magsafe charger for a bit, but overnight it's only ever plugged into the slow 5w apple charger. Never had any battery issues with any iPhone doing it this way.

Too many things in life to worry about without adding a phone battery into the stress mix lol 😂
Use different chargers for day and night, and you're doing fine.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
Credible/corroborating research (eg link1 and link2) all seem to say the same thing - avoid high states of charge (SoC) for longest service life. I personally like the ‘charge only what you need, and when you need it’ approach.

Low low SoC appears stress-free/fine for daily use devices (per the research links). IMHO, the ‘keep it above 40%’ comes from long-term storage advice where self-discharge eventually risks the batt falling below critical minimums. That’s not an issue for daily use devices.

With today’s automation options (smartplug/shortcuts and USB dongles), after one-time set-up, it’s now inexpensive/effortless to program custom charge optimizations where you can plug-in once/day and forget it, just like everyone else. Of course, this is assuming your usage pattern is suitable. I personally wouldn’t bother to plug-in a second time per day just to save battery, but if I’m going to plug-in once/day anyway, then why not use a better charge optimization to preserve batt?

Does it work? I’ve recently run battery meter recalibrations/full rundown tests on my 3yo iPhoneXR and previous 10yo iPhone5 and am currently running the test on my 11yo iPad2 streaming YT movies (what it looks like so far). FWIW the older devices were generally cycled 80-20 (plus 3yrs in storage), while I’ve shifted the XR from 75-25 down to 65-15, based on above research. The XR has seen 8% SoC way more than 80%.

(What can I say… I’m a battery/efficiency hobbyist and just like testing this stuff…. for ‘science’)
Wow, thank you for such a detailed explanation, some of your statements seem to be very professional, I need time to read them carefully. Thank you.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
This is the general rule for lithium ion batteries though not specifically iPhone batteries.
iPhone batteries likely aren’t capable of the cycles stated below but the trend will be the same: the farther the iPhone battery gets discharged, the more stress it puts on the battery

"You can do over 40,000 charge/discharge cycles when going from 30% to 70% only.
Or over 35,000 charge/discharge cycles from 20% to 80%;
28,000 cycles from 10% to 90%;
15,000 cycles from 8% to 92%,
7,500 cylces from 6% to 94%,
and the capacity reduction goes faster and faster, finally reaching 500 cycles when recharging from 0% to 100%."
Thanks for such a detailed explanation. From this point of view, it is best to charge when the remaining power is more than 30%. Don't wait until the battery is very low to think about charging, and don't run out of power too quickly. This should be the battery friendly way.
 

now i see it

macrumors G3
Jan 2, 2002
9,698
19,442
I’ve shifted the XR from 75-25 down to 65-15, based on above research
Even the NASA satellite battery research links you provided stated a few times that charging to a max of 3.92V is the sweet spot.

65% maximum charge on an iPhone battery is below 3.92V. It’s doing more harm than good.
The sweet spot for iPhone batteries is 75%.
 

reppans

macrumors regular
Dec 2, 2006
235
125
Even the NASA satellite battery research links you provided stated a few times that charging to a max of 3.92V is the sweet spot.

65% maximum charge on an iPhone battery is below 3.92V. It’s doing more harm than good.
The sweet spot for iPhone batteries is 75%.

We agree with avoiding high SoC, but differ on the lower end SoC… all three of the research links I’m now following indicate that the lower the peak and average SoC you can conveniently maintain, the better. I do not see ‘more harm than good’ from cycling lower in the range in those articles… unless of course you can provide additional links to credible batt research. I’d be interested in seeing them.
 

MagOnetech

macrumors member
Original poster
Oct 31, 2022
38
7
USA
iPhone 11 here but still relevant to the thread.

I keep mine charged between 20 and 80%. Phone is 24 months old and I'm a heavy user...battery health is 89% which is decent.
Congratulations! That's a pretty good state indeed, since you've had it for two years.
 
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Tsepz

macrumors 601
Jan 24, 2013
4,610
4,374
Johannesburg, South Africa
I'm using an iPhone 13, and my phone typically has 20% battery left, which I'll be charging.

I have seen some sayings that you should charge your iPhone with 40%-50% remaining power. This is the most friendly way to the battery of the mobile phone and can better protect the battery of the phone. Is this believable?

I want to discuss this with you guys. So how much power do you have left on your iPhone when you charge it?

In addition, does charging for a long time have an impact on the iPhone battery? Like charging it all night.
I charge my phone when and if I want to. At the end of the day the battery is going to degrade no matter how many “battery charge tips” I am given.

The other morning I was on my way to the stadium for a game, my phone was at 95%, I plugged it in in my car, unplugged when I got out the car at the stadium at 100%. 🤷‍♂️

When we were leaving the stadium that night my battery was at around 70%, I plugged it in anyway as I was planning to drop my car home and Uber out to meet some friends, so wanted my phone to be 100%.

I plug in when I want, not depending on the battery %.
 

Ifti

macrumors 68040
Dec 14, 2010
3,472
1,873
UK
I generally charge my phone when it gets to around 20%
I usually let it charge to around 80-90%
If I'm going to be out a lot and know I won't be able to get to a charger easily, then I'll go to 100%.
I do not leave it at 100% and remain connected to the charger for too long (eg overnight). As soon as I notice it's at 100% I remove it from the charger.
I do not use magsafe/wireless charging as I do not like the extra heat it generates.

There is a reason why Apple decided to implement 'Optimized Charging', which charges the handset to 80% and then gives it the last boost to 100% when it 'thinks' you are going to unplug and use the handset. They do not recommend teh handset sits at 100% and connected to the charger for too long. I simply mimic this behaviour, although in a manual fashion.....

13 months into my 13 Pro Max and battery health is at 100%
 
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