iPhone 80% Charging Limit

One more data point: My iPhone 15 Pro shows 100% capacity (yes, one hundred percent) and 134 cycles after the first year. I have been keeping it below 80% almost all of the time, only charging it all the way up on the few days when I expected (usually wrongly) that I would need more oomph to get through the day. And I don't do wireless charging at all.

I just checked mine and it's at 98% after 227 cycles.

A few weeks ago, before I started running 18 and 18.1 betas, it was still at 100% health. I think the charge limit works great, what probably degraded my battery is the impact of discharging it below 20% too often since I started using the betas.

This argument that Apple made it "really smart" is hard to sell. My Apple Watch Ultra 2 has optimized charging enable, but rarely limit the charge to 80%, despite my daily routine of using only about 40% of the battery and recharging it.

For me personally, 80% charge is more than ample for a typical day (not for a travel day), and 100% charge does not extend the life enough to significantly improve convenience. Now if it were the difference between, say, 6 days and a full week, that would be valuable enough for me despite the relatively small percentage difference. (I'm not about to give up the full smartphone capabilities but I do miss the whole-week battery life of the old Nokias.)

My iPhone XS is at 77%. Optimized charging is on. And I have it on a charging stand all day long now that I've been working from home since March 2020.

I went and checked my 15 Pro: full capacity, 152 cycles. I charge via MagSafe overnight, and have an automation to force Low Power mode below 25% battery. Very seldom do I need above 80% to get through the day, or go below 20%.

Of course iOS 18 hasn’t really made a dent (and I ran no betas).

Coconut Battery opens a web page showing how your battery fare against others.

I replace at Apple my iPhone battery when it reaches about 80% of original capacity. Every two to three years so for my iPhone 7 twice already. I know and use a fair amount of it's functions now so won't let it go for a bit longer.

Disabling background app refresh for all apps, also a good security option, and switching the phone off at night, letting the battery re-align chemicals, proved useful to prolong it's life. And in general disabling any un-necessary background activity, screen activation and wireless communication.

How reliable are these measures of battery health? How are they calculated? The most likely explanation of all of this is that this number is mostly nonsense, and people get worked up about differences that probably don't even exist in the real world.

My nearly four yearsv old iPhone 12 Mini reports a capacity of 88% (but weirdly, no cycle count). A shortcut notifies me when the battery charge exits the 20-to-80-percent range, but I don’t obsess about keeping it within these bounds.
On a typical day, the phone may be in active use for multiple hours, albeit predominantly with the screen off. I can’t remember a single time of desperately needing the “missing” 20%.

I have charging limit enabled in an Android phone that's used exclusively as a development tool (i.e. nearly every time it's on, it's connected to my computer). After almost 2 years, I have 98% battery health with 91 cycles. I don't have hard data to compare this to, but it does seem to me substantially better than previous phones I kept plugged in too often.

As much as I like this feature for the specific use case, I don't think I'd enable it on my daily phone if I had the option. I honestly expected better results than Juli's, but if nothing else I'd live in constant fear of not having the extra juice for an unplanned occasion.

@Rod Agreed, I see no evidence (and have never seen one) that Apple made it "really smart". At best I see a company that vacillated over the years, taking way too long to even implement the smart charging mode.

I agree the primary goal for batteries today should be longevity over years, rather than duration over a day. My 4 year old iPhone 12Pro is amazingly still at 82% capacity. I think Apple has told me they won't replace it under (continuing) AppleCare+ until it's below 80 … … …

John Gruber wrote:
> I’m so glad Clover ran this test for a year and reported her results, because it backs up my assumption: for most people there’s no practical point to limiting your iPhone’s charging capacity.

I see a very different outcome of the experiment.
Juli Clover’s phone lost only 6% capacity in a year, while the other two lost on average almost twice as much.

> All you’re doing is preventing yourself from ever enjoying a 100-percent-capacity battery.

A new phone’s capacity is so big that 80% almost always gets you over the day. You don’t need the 20% in the first years, and can save it for later.
I also set the 80% limit, and only switch that off in holidays e.g. to track snowboarding. GPS running all the day depletes the battery quite quickly.
Thus I pretty much ran the same experiment as Juli did, but with 2-3 weeks where I set the limit to 100%.

However, usually my own 15 Pro Max sits most of the day in its dock, connected to my Mac, since I am writing software for it.
It is probably exactly as old as Juli’s (I bought it on the very first day), but I only had 79 cycles in that year, and it still has 99% max capacity.
I bet if I would have set it to 100% while it sits in the dock on average 20 hours a day, I would have cooked the battery.
All my former iPhones did NOT have 99% left after a year of developer usage, connected to power most of the time.

> Apple has put a lot of engineering into making that really smart.

And the smartest move was to let the user limit the max charge. Lithium batteries degrade way faster when charged over 90%.

Conclusion: Letting the user set a max charge limit is a very good way to extend the battery life.
The only question is, what took Apple so long to finally implement it? Android has had that for years…

Greetings from Vienna,
Marc

P.S.: If you reach 80% or less of the original capacity within two years, in the EU that’s a warranty case where Apple (or rather the dealer that sold you the phone) must repair it (new battery for free).
AFAIK to get the same coverage (as all EU citizens get for free) in the USA you must buy AppleCare.
I would love to buy AppleCare for all my Apple devices, if the start point was 2 years after purchase, when the EU warranty expires…
Paying for 3 years of insurance cover when you already have two years for free is pointless.

@Marc If it were just the three phones in Clover’s article, it does seem like a significant difference, percentagewise. However, I would have hoped to see less degradation when using the limit. And reading the other user reports makes the benefits less clear. Maybe there is just a lot of variability from other factors.

If I had to do it again, I would probably use the limit because, as you say, 80% of the new capacity is usually plenty. And iOS 18 makes it easier to temporarily override it.

And I’m going to try the limit going forward because I’ve now reached the point where I need to use an external battery for longer excursions, anyway.

Regarding the watch, if you’re on Watch OS 11 you may be having the issue I ran into. There was really fast battery drain and the graph of the battery level was just blank. I found a thread on Apple support forums about disabling live activities and photo memories. I don’t have any photos synched to my watch so I’m not too familiar with the latter feature, but turning off live activity seems to have done the trick.

@Joe I’m still on watchOS 10, but good tip, thanks.

One more data point for the pile:

As of September 24, when I first read this article and got around to checking my own 15 Pro:

100% capacity, 121 cycles. I only disabled the limiter a couple times while I've had it, so the vast majority of my over-80% charges were from the phone itself deciding it ought to charge to full.

From what I remember Siracusa saying, going from 99% to 100% and back repeatedly is probably the worst thing you can do for your battery. My phone spends a lot of time in StandBy and is only occasionally off its stand, so I figure that the 80% limiter is better for me than it is for people whose phone-charging ebbs and flows are more normal.

> My 2 1/2-year-old Apple Watch SE is down to 76% battery health. Apple recommends that I service it, but I’m not sure it’s worth $99 for a new battery when there will probably be a new SE soon. What’s strange is that the watch usually easily lasts through the day, but sometimes it will run out of power around 5 PM for no apparent reason.

I have the same model as you and see the same behavior. Sometimes it won't last through a ~3 hr eFoiling session. Often when this happens the shell of the watch feels hot. Maybe a runaway process.