If you don't typically need more than 80%, it's not crippling, and it could extend the lifetime of the battery by 50% before you have to exchange it. That's not a small amount.
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In-Depth iPhone Battery Experiment Pits Slow Charging Against Fast Charging
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This is a great & well-executed test, but unfortunately 500 cycles is just not enough - & testing more would be an even larger burden - so no complaints here.
All these batteries are specified for between 500 & 1000 cycles using the factory charger that came with the device, so that is what they do.
The question is (& the reason I slow-charge my devices): how much longer does the battery perform well over the specified minimum? IMHO a premium device should handle at least 5 years of daily usage before degrading to the point of needing replacement. Slow-charging Li-Io cells the final 20% of capacity from 80-100% (& not running it down below 15%) at lower temperatures makes a significant difference in extending the age of the battery beyond the specification. This is why electric cars manage their battery packs this way.
All these batteries are specified for between 500 & 1000 cycles using the factory charger that came with the device, so that is what they do.
The question is (& the reason I slow-charge my devices): how much longer does the battery perform well over the specified minimum? IMHO a premium device should handle at least 5 years of daily usage before degrading to the point of needing replacement. Slow-charging Li-Io cells the final 20% of capacity from 80-100% (& not running it down below 15%) at lower temperatures makes a significant difference in extending the age of the battery beyond the specification. This is why electric cars manage their battery packs this way.
Considering that this is a short test and that battery management is always in play regardless of charge power capability, this isn't surprising. I'm more interested in how to keep a device battery viable beyond 3 years.
Of course it is very well known that leaving your device in the sun very seriously degrades Lithium batteries, and it isn't surprising that a person will do so at least once over a multi-year period.
Of course it is very well known that leaving your device in the sun very seriously degrades Lithium batteries, and it isn't surprising that a person will do so at least once over a multi-year period.
I don’t know about this one.
My 15 Pro always gets warm when using a 20w charger but never with any slow charging cable, so heat is a bigger issue with fast charging.
Even charging my iPhones at the max wireless speed they support, all the way to 100%, I usually end up with a 100% reported battery health after a year or extremely close to it.
After a year my 16 PM had 100%, 15 PM 100%, 14 PM 99%. 13 PM I think was 99% and so on. People are just over thinking it.
Interestingly that the conclusion, charge fast or slow was also born out with studies of ev batteries. The difference though is “minor degradation” due to charging ev batteries to 100% can have much more Expensive consequences over time.
HTX Studio this week shared the results from a six-month battery test that compared how fast charging and slow charging can affect battery life over time.
Using six iPhone 12 models, the channel set up a system to drain the batteries from five percent and charge them to 100 percent over and over again. Three were fast charged, and three were slow charged.
Another set of iPhones underwent the same test, but with charging initiated at 30 percent and stopped at 80 percent, so the iPhones were always in that range.
Prior to the experiment, the capacity for each phone was tested, and after 500 cycles, the capacity was tested again. The results suggest there is minimal additional battery drain from fast charging, but keeping an iPhone between 30 and 80 percent charge could be minimally beneficial.
HTX Studio concluded that the best way to charge an iPhone is "however you like," without overthinking it and trading mental energy for a tiny bit of battery life. The same video also includes Android tests, and is well worth watching in full for those curious about the effects of fast charging.
Article Link: In-Depth iPhone Battery Experiment Pits Slow Charging Against Fast Charging
Where as my iPhone battery is $89.
For my use, the 80% charge limit makes sense. I leave my phone on a Belkin 2-in-1 MagSafe charger almost all day.
During my holidays, I remove the charge limit.
During my holidays, I remove the charge limit.
I needed to go to the emergency room at the hospital one night with my son. Took my iPhone and AirPods off the charger.
Once I got there and my son was admitted, I started calling and texting friends and family.
I quickly noticed that my battery was a bit under 80% on both devices, realising it was the ”optimised charging” in effect keeping my state of charge at 80% ”until I need them”. Turns out the only time all year that I really needed 100% charge, the phone didn’t know I needed a full charge, and that’s because there is no such thing as artificial intelligence. 🤖
That was when I turned that function off forever. I will never trade a fully charged battery against battery health longevity. And you know what? I can’t discern any notable difference in battery health. It’s the same.
And my son was fine in the end. ☺️
Once I got there and my son was admitted, I started calling and texting friends and family.
I quickly noticed that my battery was a bit under 80% on both devices, realising it was the ”optimised charging” in effect keeping my state of charge at 80% ”until I need them”. Turns out the only time all year that I really needed 100% charge, the phone didn’t know I needed a full charge, and that’s because there is no such thing as artificial intelligence. 🤖
That was when I turned that function off forever. I will never trade a fully charged battery against battery health longevity. And you know what? I can’t discern any notable difference in battery health. It’s the same.
And my son was fine in the end. ☺️
Absolutely. However when your battery is a minor part of the overall cost it’s one thing. When your battery costs exceed the value of the thing it’s powering (such as an ev) it’s quite another.
I’m one case, my phone I have a small amount of managing going on. I charge to 80 and if I think I need more I charge to 100. My ev is different management. I don’t micromanage but avoid letting the car sit overnight at 100%.
This result has been confirmed again and again.
80% charge limit: total waste of time.
“Slow” charging your iPhone: total waste of time.
Doesn’t matter what the “believers” think, or say. These data, time and again, confirm it. Waste. Of. Time.
80% charge limit: total waste of time.
“Slow” charging your iPhone: total waste of time.
Doesn’t matter what the “believers” think, or say. These data, time and again, confirm it. Waste. Of. Time.
Meh, I only tend to use 30-50% of the charge in an average day so I’m not really limiting anything by only charging to 80%.
Total waste of time. Negligible difference that no one will ever care about. Ever.
You should actually watch the video, or read all the posts in this thread.
Sure, for most people the difference is small, but "total waste of time" it is not.
It all depends on how we use our iPhones and what we want to achieve at the end. I personally try to get as much time of the battery use as possible, as I usually pass my devices on after having used them for 2-3 years. I alternate between an iPhone (about 60% use) and an iPad (about 40%).
Once Apple introduced capped charging, I set it at 80% from day one on my iPhone 15, which I was using since October 2025 and this summer lifted it to 85%. I was using it without any limitations (incl. running early betas on it) and would plug it in every time I was in a car (slow wired charger) or to Apple’s 20W power adapter if I needed a quick top-up. I would then charge it overnight with Apple’s 5W wired charger. When I was travelling, hiking, etc., I would charge it up to a 100%. The results were good - after two years of normal use my battery health stayed at 93%, so I did not need to change the battery before passing the iPhone over.
Once Apple introduced capped charging, I set it at 80% from day one on my iPhone 15, which I was using since October 2025 and this summer lifted it to 85%. I was using it without any limitations (incl. running early betas on it) and would plug it in every time I was in a car (slow wired charger) or to Apple’s 20W power adapter if I needed a quick top-up. I would then charge it overnight with Apple’s 5W wired charger. When I was travelling, hiking, etc., I would charge it up to a 100%. The results were good - after two years of normal use my battery health stayed at 93%, so I did not need to change the battery before passing the iPhone over.
You know what's a total waste of time? Waiting an extra hour to charge the last 20%.
You can avoid this by charging overnight, but I don't bother with it because I have to plug it in anyway for it to last the whole day. I would rather fast charge with a cable as needed.
Charging to 100% is only worth it if you'll be out all day.
You can avoid this by charging overnight, but I don't bother with it because I have to plug it in anyway for it to last the whole day. I would rather fast charge with a cable as needed.
Charging to 100% is only worth it if you'll be out all day.
Exactly. This topic has been discussed to death in EVs. Don’t stay at 100% for a long time. If your phone is mostly plugged in— say on your office desk during a workday— then limiting it to 80% has significant help for your battery health. When you actually need to use the battery, like on the weekend, charge it up to 100% as you like, just make sure that it doesn’t stay at that level unused.
People here seem to think the battery tech was perfected, you don't have to be careful anymore, but I still see people complaining about their battery losing capacity fast.
While my anecdote of one - my ipad 1 battery still works decently. My ipad 2 (year 2011) still has a month of standby - wifi off, everything off, I only use it as a timer.
While my ipad pro M1 strangely has only a few days of standby.
My ipod touch 1 (year 2008) the same - has quite a decent battery life. Same for my iphone 4s. But I try to avoid storing them with zero battery.
While my anecdote of one - my ipad 1 battery still works decently. My ipad 2 (year 2011) still has a month of standby - wifi off, everything off, I only use it as a timer.
While my ipad pro M1 strangely has only a few days of standby.
My ipod touch 1 (year 2008) the same - has quite a decent battery life. Same for my iphone 4s. But I try to avoid storing them with zero battery.
Sure thing buddy. Science disagrees with you, but call people idiots because why not.
Have the same feeling as all my devices are kept constantly fully charged if possible and used plugged in (if possible) and battery degradation is slow. 80% charge limit has no use for me.