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iPhone 15 Pro Damaging to keep your phone on the charger most of the time?

bbates123

bbates123

macrumors 6502a
Original poster
Jul 2, 2010
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I normally keep my phone on a little stand next to my desk while I'm working so I can see as notifications come in. Now with the new 80% charging limit option, I'm wondering if I could just keep it propped up on a MagSafe stand instead and let it keep that 80% charge while I'm working, that way I don't have to worry about running out of battery life during the day.

That got me to thinking, is there any evidence that keeping a phone charging most of the time is damaging to the battery, especially if it's not allowed to go to 100%. I searched but couldn't find any studies around this.
 
That’s exactly the scenario the new 80% charging limit was designed for.
Yes, set the charger to the 80% hard limit and leave the iPhone plugged in indefinitely. The battery won’t get damaged.

If you did that with it set to 100% charge, the battery lifespan would be a lot lot less
 
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There are studies based on general Li-ion that show a high state of charge reduces battery capacity over time. There are no specific studies with iPhone or iPad, but results should carry over.
 
JPack said:
There are studies based on general Li-ion that show a high state of charge reduces battery capacity over time. There are no specific studies with iPhone or iPad, but results should carry over.
Click to expand...
But the question is, is 80% considered a high enough state of charge to qualify?
 
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I keep mine on the MagSafe charger for over three years, over night, and my battery is now at 87% health. With my iPad Pro. 24/7. I never unplugged the charger. Will retire my iPhone 12 Pro next year with the 16 comes out. I just don’t worry about this.
 
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now i see it said:
If you did that with it set to 100% charge, the battery lifespan would be a lot lot less
Click to expand...
is that true? I thought years ago Apple made it so when the battery charges to 100% it stops charging and losing some charge before recharging to 100% - to protect the battery from damage.

It‘s asinine to have to keep our batteries at 80%
 
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sviato said:
is that true? I thought years ago Apple made it so when the battery charges to 100% it stops charging and losing some charge before recharging to 100% - to protect the battery from damage.

It‘s asinine to have to keep our batteries at 80%
Click to expand...

Yes, it's true. Extreme states of charge means the electrode potential is high which leads to undesirable chemical reactions.

In short, avoid charging to 100%.
 
bbates123 said:
But the question is, is 80% considered a high enough state of charge to qualify?
Click to expand...

It's a sliding scale, not a binary effect. The higher the charge, the fewer cycles and less battery capacity is retained.

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To throw in some evidence to the contrary, my 2011 MacBook Pro spent a lot of its life plugged in and at 100%, and that battery lasted for eight years before crapping the bed.
 
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eicca said:
To throw in some evidence to the contrary, my 2011 MacBook Pro spent a lot of its life plugged in and at 100%, and that battery lasted for eight years before crapping the bed.
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Sure, I don’t doubt that. I’ve had laptop batteries last 10 years or more but there’s a difference between lasting ten years and running a laptop on the same battery for hours on end. The laptop batteries that lasted 10 years would only hold a charge for a little less than an hour.
 
Heat_Fan89 said:
Sure, I don’t doubt that. I’ve had laptop batteries last 10 years or more but there’s a difference between lasting ten years and running a laptop on the same battery for hours on end. The laptop batteries that lasted 10 years would only hold a charge for a little less than an hour.
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Mine was doing 4-5 hours until the day it crapped itself.
 
So I have been doing this since I started using iPhones. Put it on t charger at 50% and charge it to 100% every night and my previous iPhone 14 Pro which I just traded in for 15p,the point I’m trying to make is that after a year and 3 months doing it this way,my 14p was down to 95% at moderate to heavy usage
 
If you have a 15 Pro, am I correct in assuming that you upgrade frequently, maybe every year? If so, it doesn’t matter, do whatever you like.

If someone keeps their iPhones for a long time and updates iOS, nothing matters, iOS updates will obliterate battery life regardless of battery health. Sure, in that case, battery health will help, but would you really want to put yourself through all the trouble of battery preservation just to see battery life plummet by 60% due to irreversible iOS updates anyway? As soon as health drops a little (and it will in five years, regardless of battery care), five major updates will obliterate battery life, even after a battery replacement.

If someone keeps their iPhones for a long time and never updates iOS, nothing matters, as battery health is completely irrelevant if the iPhone is on its original iOS version.

The point is... it doesn’t matter.
 
I put my iPhone 13 on the charger when the battery level is around 25-30%, and I let it charge until it’s 95% then I pull it off the charger. I never allow any battery, regardless of device, to charge without it being monitored. Oh, and I only need to charge my iphone 13 every couple days. I’m guessing I’m not a power user.
 
CopCarJeff said:
So I have been doing this since I started using iPhones. Put it on t charger at 50% and charge it to 100% every night and my previous iPhone 14 Pro which I just traded in for 15p,the point I’m trying to make is that after a year and 3 months doing it this way,my 14p was down to 95% at moderate to heavy usage
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Since 2009 (first smarphone) I have put every phone on charger at night and had the screen on all night as a bedside clock. For my iPhone 6s Plus it took six years for my battery hit 79% and warrant replacement. That's with 3 summers riding around in a car with no A/C and rolled up windows during Phoenix, Arizona summers.
 
I've never had a battery degrade faster than it was supposed to other than my 14 Pro Max I had last year (It seemed that most 14 PM and Pro's had that problem.) from keeping the charger connected to the phone. I keep it at 100% until I'm ready to go out with it so I watch YouTube, surf the web, text, and social media while it's plugged in a lot. I'm still at 100% with 45 cycles on my launch day 15 Pro Max. Until I have battery degrading issues, that's the way I'll use my iPhones.
 
bbates123 said:
But the question is, is 80% considered a high enough state of charge to qualify?
Click to expand...

According to battery university the optimal state of charge where the battery is in the lowest tension is 3.92V, which roughly equates to 65% state of charge. 80% seems to be pretty reasonable for aging, going much above 85% or so where where most of the wear starts to happen.

Personally I use AlDente on my laptops set to 70% for plugged in use, and when going out and about will typically top up to 80-85%. Don't believe there's such a solution for iOS though.
 
To add to OP's question - is it charge to full or raw cycles? I had an 11 Pro Max which I constantly had connected to a charger and the battery after 4 years and had was still at 85% health. It seems counterintuitive to have a MagSafe charger right there in front of you and to not leave it there when you are not going out or about. I get the 80% thing, but OP's question was always leaving on the charger. Again, I never had issues with this approach with the 11 Pro Max.
 
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Batteries age normally from usage and from time. It’s well known that heat is a permanent detriment to battery life.

Having said that I try to reasonably use the battery of my iPhone. I don’t discharge to zero and don’t keep it charging at 100% for long.

Over time the peak current a battery can provide will drop. When the hardware requires more current than a battery can provide the phone will shut down. (Or get throttled)

Use the phone as you want. Don’t worry about upgrading iOS versions, there is little evidence to suggest battery life is any more than nominally affected.

If needs an old phone can be given some rejuvenation in the form of a new battery for $59.
 
I7guy said:
If needs an old phone can be given some rejuvenation in the form of a new battery for $59.
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Where are you shopping?

My last battery replacements were around $100 each for a 6 Plus and an SE2. And Apple refused to replace the battery on the 6 Plus.
 
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