iPhone 16 Pro Max 80% Charge Limit: One Year Later, Was It Worth It?

[FeliApple]

For me the biggest issue is that you're either upgrading every year or two; in which case you could absolutely thrash your battery and you'll likely be fine by the time you trade or retire the device anyway. Or you've got AppleCare, in which case Apple will replace the battery once it hits 80% capacity (the capacity you're already artificially limiting yourself to) regardless of how you've treated it. Or you've been frugal by keeping an iPhone for several years and not paying extra for AppleCare, so the cost of a new battery (which is quite reasonable, IMHO) is still a very good value proposition overall.

I just replaced a 13 Pro that I got on launch day, with a 17 Pro Max that I also got on launch day. That 13 Pro was wirelessly charged almost exclusively because I got sick of dealing with terrible lightning cables. It got hot all the time and frequently rode around with a magsafe battery attached (pretty much every weekend; hiking with GPS apps or things like that, I just pre-emptively stick one on there.) It was right at 79% when I replaced it with the 17 Pro Max. In fact I kept the phone and already have an appointment with Apple to get the battery replaced. But that's 4 years of abuse and thrashing and a device that ultimately still had decent battery life (still usually lasted all day, for me). It would cost $89 for me to get a new battery if I didn't have AppleCare One which is going to pick up the tab this week when I go replace it anyway.

I really do think when you kinda zoom out, babying the battery of an iPhone is a juice that just isn't worth the squeeze.

This, and another interesting factor for long-term use are iOS updates.

I am somebody who keeps iOS devices forever, doesn’t update iOS, and doesn’t replace batteries.

As a result, battery health is irrelevant. The reason battery life drops with battery health is that newer iOS updates have higher power requirements. They demand more. Liquid Glass’ animations on iOS 26 consume 13 times more power than iOS 18.

(See this comparison:

)

I have an iPhone 6s whose battery failed prematurely, and it was below 80% after less than a year.

Since day one, that 6s has been running (and continues to run) iOS 10.0.

It gets like-new battery life after about 1400 cycles. It shows about 68-70% health, it stabilised, and dropped about 10-13% health in 1100 cycles and 8 years.

The iPhone is no longer in active use, but I last tested it two years ago. It still had like-new battery life, giving me about 7-8 hours of SOT with light use. Why would I care?

My six-year-old iPhone Xʀ running iOS 12 is at 89% health. Why would I ever care about battery health? Also, what happened with the Xʀ? It is now in a drawer, unused, as I’ve upgraded to the 16 Plus seven months ago.

Batteries outlast devices in my experience, so caring is pointless. If you are somebody who keeps iOS devices for years on end and updates iOS, newer iOS versions will kill your battery life even if you have 100% health, so why bother with limiting yourself with charge limits if iOS 26 will kill your 13 Pro regardless of health?

The device is either old enough so as to be killed by updates regardless of health, or new enough so that its iOS version is so efficient that health doesn’t matter.

 

[yadmonkey]

I have never understood this. Wireless charging is the most heat-inducing, inefficient, battery-health-affecting charging method.

Why would you go through the trouble of losing 20% capacity on day one by limiting charge just to preserve battery health… whilst choosing the most heat-inducing, battery-health-killing method of charging?

I’d say that at least if you’re going to limit the battery and if you’re going to lose a massive amount of capacity on day one to do so, the fastest charging speed ought to be 5w. Otherwise it’s just pointless.

And for the record, I think it is pointless anyway. I’ll never limit my battery charge.

80% is enough for me, else I wouldn't have left it like this for 15 months.

Having lost only 3% of my max capacity, this heat issue doesn't seem quite as onerous as you're making it out to be. Mine just gets a little warm, but I intentionally chose adapters that weren't the most rapid. Rapid charging by cable probably produces at least as much heat, if not more.

I agree that the benefits of the 80% limit are questionable in light of what is being shared, but there are confounds that few here have recognized, like the use of rapid charging and variations in maximum charge on batteries off of the assembly line.

 

[Hostilityxbl]

I can almost guarantee apple isn’t basing battery health on the actual usage or health of the battery
But instead if basing it on the phones uptime and number of charge cycles

 

[dongding]

In my observed opinion, the heat generated during MagSafe charging decimates batteries.

 

[dongding]

The limit to 80% is only really for if you keep your phone plugged in all the time. It is bad to run the battery on charger and continuously at 100% (I killed a macbook pro battery completely in 1.5 years doing this). But if you are taking the phone off the charger every day then the real killer is cycles, more cycles = more deterioration.

 

[dongding]

I can almost guarantee apple isn’t basing battery health on the actual usage or health of the battery
But instead if basing it on the phones uptime and number of charge cycles

This is part of it, but they do also measure maximum voltage because voltage drops with capacity loss. The internal battery management controller does this task.

 

[FeliApple]

80% is enough for me, else I wouldn't have left it like this for 15 months.

Having lost only 3% of my max capacity, this heat issue doesn't seem quite as onerous as you're making it out to be. Mine just gets a little warm, but I intentionally chose adapters that weren't the most rapid. Rapid charging by cable probably produces at least as much heat, if not more.

I agree that the benefits of the 80% limit are questionable in light of what is being shared, but there are confounds that few here have recognized, like the use of rapid charging and variations in maximum charge on batteries off of the assembly line.

Yes, I agree that yours looks good. You know, as I said, I think that limits are pointless, as (although I haven’t made a scientific study) I’ve checked thousands of results (mostly because I’m curious and I like tracking my own cycle count and to see how others fare), and there really is no difference in general. 97% and 212 sounds good, but that’s probably reachable with 100% charging too. For every example there is a counter-example of somebody who just doesn’t care about limits and has similar or better numbers. You can see that throughout this very thread.

That’s why my only two precautions are to avoid heat and charge with a 5w wired power adapter (the small cube). And don’t be mistaken: I do the slow charging because I truly don’t need fast charging. If I did, I would just charge faster. Unless I noticed the device getting hot, which is undeniably the #1 battery killer.

 

[joaocdestro]

iPhone 15 Pro Max

1st charge Jan 2024
Charge Limit set to 90%
Cycles - 355
Battery Capacity - 95%

During my work and at my car it stays connected 100% of the time, to avoid cycles.

 

[rayzor2k]

I don't think charging to 100% is the problem when it comes to battery degradation. Once it gets to around 80%, the charging gets super slow. You can feel your phone cool to the touch. I think the main culprit is heat. It is worse if you use regular wireless chargers or you let your battery get too low (you spend more time fast charging it until around 50% when it slows down again). Sure you can slow charge your phone, but that is so inconvenient!

I am going to test cryo fast wireless charging this year when I get my new phone.

 

[DeanCorp]

My 15 Pro at trade in was at about 85% capacity with over 600 cycles. I charged it to 100% nearly every day with adaptive charging turned on. My understanding is that it's not the 100% charge that is bad itself but keeping it there for an extended period.

What I’ve noticed is that all these people flexing 100% battery health have very low cycle counts. Most that I have seen with high cycles have lower health. I’m yet to see anyone with 450+ cycles showing 100% capacity.

 

[jmarsh5]

100% charge with optimized charging on. I’m satisfied with this