I think the idea is that when you do need 100% capacity, you have preserved your battery’s ability to deliver that.
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Apple's 80% Charging Limit for iPhone: How Much Did It Help After a Year?
- Thread starter MacRumors
- Start date
- Sort by reaction score
They are two different things. One is the Battery Level/Charge and one is the Battery Health. The design/chemistry of Li-ion batteries is that letting the charge fall below 20% or go over 80% wears them out more (like running a car at the redline -- within limits but don't expect the engine to last as long). As such not letting the charge fall below 20% before charging and not charging above 80% should extend the life of these types of batteries all else being equal.
The Battery Health is the battery's estimated ability to hold a charge. It represents the accumulated wear on the battery which includes regular as well as deep discharge/charge cycles, exposure to extreme temperatures, etc.
Apple's 80% battery health threshold is somewhat arbitrary and unrelated to the 80%->20%->80% cycle above. It my experience Apple's 80% battery health measure is not linear and practically speaking 80% battery health is close to 0% usable. When I kept my last iphone battery through to 80% battery health, it had at most a few hours of life and sometimes power failed the phone as soon as I took it off the charger. A battery @ 80% health may be able to hold some amount of mAh but not at a voltage that the phone can use.
I believe it helps. On my iPhone 15 Pro Max, with a cycle count of 275, I'm still at 100%. More than 95% of my charging is done via Magsafe or Qi wireless charging, charging overnight every night on the Magsafe charger. An 80% charge is enough for my all day use at least 90% of the time and of the other 10%, some sort of charging capability is readily available. The only time I've had real issues is when using an app that didn't turn off location services as it should have.
With the iPhone 15 models that came out last year, Apple added an opt-in battery setting that limits maximum charge to 80 percent. The idea is that never charging the iPhone above 80 percent will increase battery longevity, so I kept my iPhone at that 80 percent limit from September 2023 to now, with no cheating.
My iPhone 15 Pro Max battery level is currently at 94 percent with 299 cycles. For a lot of 2024, my battery level stayed above 97 percent, but it started dropping more rapidly over the last couple of months.
I left my iPhone at that 80 percent limit and at no point turned the setting off or tweaked it. There were some days when I ran out of battery because I was without a charger for most of the day, and there were other times that I had to bring a battery along to make sure I didn't run out of power. It wasn't always convenient to keep it at 80 percent, but there were days when it didn't have too much of an impact.
Let me know your current battery capacity and cycle count in the comments below, and weigh in on whether you think Apple's limits are worthwhile.
Article Link: Apple's 80% Charging Limit for iPhone: How Much Did It Help After a Year?
Attachments
Last edited:
Think of it as SSD, if the drive is around 80% full or less then it does not slow down and if it inches closer to 100% the speed drops.
Battery chemistry like fueling a petrol thank needs time for the air pressure and vapour to accommodate in a tank. When the pump reports your petrol tank is full it not full to the brim as petrol vapours and air pressure need room in that tank as well.
What counts as a cycle? Any time on the charger? Only when it reaches 80%? Only when it reaches 100%?
Hah, that would be too simple. A cycle is when the sum of charging is ~100%. So e.g. you charge 2 days 50%, that's one cycle. Or you charge 3 days 33%, that's one cycle. Etc.
I’d be interested in an update here. It’s important to limit to 80%, yes, but it’s also important not to let your battery drop below 20% too often. I charge in the car and at my desk at work to ensure I always have battery. I also never, never allow my phone to be charged via MagSafe anymore under any circumstance.
My launch iPhone 16 Pro Max is now still at 100% battery following those steps.
Let’s see where it’s at in November, when, if there’s significant battery enhancements and RAM, I’ll pick up a 17 PM!
My launch iPhone 16 Pro Max is now still at 100% battery following those steps.
Let’s see where it’s at in November, when, if there’s significant battery enhancements and RAM, I’ll pick up a 17 PM!
old thread.
My launch day 16 pro is still 1t 100% with 67 cycles. I use the 80% limit. I charge at night and in my car if going for a trip of an hour or more (GPS and streaming music uses a lot of battery), but not any other times. Never MagSafe. I rarely drop below 50% charge. I check various things throughout the day on my phone and listen to music when on some long walks but don't generally watch videos or such (have other devices for that). This phone should suit me fine until maybe the 19 pro.
Last edited:
Have an iPhone 15 pro. 399 cycles 95% battery health. Charge half plugged in and half MagSafe. I don't think MagSafe will have much of an impact on battery health.
I’ve had my M3 Max MBP on 80% charge for about 3/4 its lifetime thanks to Al Dente.
It's currently at 8466/8579mAh (99%) capacity, and 147 charge cycles, which I believe is on the slightly low side.
IMO that battery condition for a 15-month laptop is crazy good. I’m very happy with this "80% experiment" and plan to continue it.
It's currently at 8466/8579mAh (99%) capacity, and 147 charge cycles, which I believe is on the slightly low side.
IMO that battery condition for a 15-month laptop is crazy good. I’m very happy with this "80% experiment" and plan to continue it.
Uhm, that battery was likely produced in June, so it's about 9 months old. You should not be surprised that it's still at 100%. With of without any steps.
I’ve now had my iPhone 15 Pro Max for just over a year.
271 charge cycles
Battery Health 93%
I started playing a game the last couple of months that I think has lead to more heat and battery drain impacting health, was at something like 96% in Jan.
271 charge cycles
Battery Health 93%
I started playing a game the last couple of months that I think has lead to more heat and battery drain impacting health, was at something like 96% in Jan.
I have three issues with this:
-it’s irrelevant for me because I don’t update iOS so battery life newer drops regardless of health. If you update and keep your device for years, updates will kill battery life, not health. This is the key factor for me.
-For yearly upgraders, this is utterly pointless. The heaviest user won’t cycle an iPhone enough in a year for this to matter.
-The variability is too high and sometimes it doesn’t even work. The OP states 94% health after 299 cycles. My iPhone Xʀ on iOS 12, which stayed on the upper bounds of battery a LOT (90%-100%) has, after… 5.5 years, unlike the OP who used it for only one, 89% health after 360 cycles. I’d argue mine is even better and I always charged to 100%. And the OP’s battery health isn’t 94, it’s more like 74%, as they’re removing 20% outright. Even with 94%, it isn’t even better in terms of the health-to-cycles ratio than an iPhone Xʀ on iOS 12 which was used for 450% of the time and stayed on iOS 12.
-it’s irrelevant for me because I don’t update iOS so battery life newer drops regardless of health. If you update and keep your device for years, updates will kill battery life, not health. This is the key factor for me.
-For yearly upgraders, this is utterly pointless. The heaviest user won’t cycle an iPhone enough in a year for this to matter.
-The variability is too high and sometimes it doesn’t even work. The OP states 94% health after 299 cycles. My iPhone Xʀ on iOS 12, which stayed on the upper bounds of battery a LOT (90%-100%) has, after… 5.5 years, unlike the OP who used it for only one, 89% health after 360 cycles. I’d argue mine is even better and I always charged to 100%. And the OP’s battery health isn’t 94, it’s more like 74%, as they’re removing 20% outright. Even with 94%, it isn’t even better in terms of the health-to-cycles ratio than an iPhone Xʀ on iOS 12 which was used for 450% of the time and stayed on iOS 12.
The notion that it's really 74% rather than 94% because this health saving feature cuts off charging at 80% is silly. The whole point is that if and when your battery capacity DOES get lower than you like you can then stop limiting at 80% to milk some more life and you can temporarily remove that 80% any time you like.
I agree that if you update your phone yearly then saving the battery doesn't matter (much) except for maybe resale value. But the point of this feature is mainly for those that DO want their phone/battery to last longer and probably don't update yearly (like me).
No offense, but this statement is ridiculous. Updates do not kill battery life.
No? Grab an iPhone 6s on iOS 15. Grab an iPhone Xʀ on iOS 18. Grab an iPhone 6 on iOS 12. An iPhone 7 on iOS 15. An iPhone 11 on iOS 18. Then tell me your screen-on time.
Maybe, but when it barely even works (if it even works at all), then I think it’s too big of a compromise, especially for me that I don’t update iOS and therefore health will forever be irrelevant.
15 Pro Max, 13 months old.
296 cycles, 98%.
I almost never charge above 80%. Wireless charge at 10-12W (maybe 15w). Keep it cool. No games.
I'd like it to last 4 years this time.
296 cycles, 98%.
I almost never charge above 80%. Wireless charge at 10-12W (maybe 15w). Keep it cool. No games.
I'd like it to last 4 years this time.
As with most things it varies by user. For me, there's zero compromise/sacrifice to use this feature. I always have plenty of battery to get me through each day. If that changes then I merely disable the feature.
So you have been updating on those phones but no longer? I tend to replace my phone every three or four years so I haven't really experienced this issue in a noticeable way but interesting that it may impact if I kept it longer and updated. I'm in a position where I pretty much have to update -- partly because I often want the new feature but especially to get the security updates. Guess I'm a bit paranoid
Read the article… it’s not going to degrade in the next 2 and a half months, as much as OP’s did in a year, in just 3 or 4 months…
My launch day 16 PM is still at 100% health with 108 cycles so far, I always charge to 100% capacity even overnight, and it's only ever been charged wirelessly using the newer faster charging MagSafe.
Optimised battery charging is turned off as always as I hate this feature, if I charge my phone I want a full charge every time.
Attachments
I haven’t willingly updated an iOS device in over a decade, but I’ve been forced by Apple a couple of times and I’ve tested some family members’ updated devices.
Note that I am not comparing them with the previous iOS version (i.e., an iPhone 11 on iOS 18 vs iOS 17), but I’m comparing them with the original iOS version (iOS 13 - 14 is good too - in this case).
After four years and four major updates, there has to be a difference with the original iOS version.
As I keep devices for a long time, I’ve tested battery health, and that’s why I don’t use any limits, because battery life doesn’t drop on original versions.