Apple's 80% charging limit for iPhone: How much did it help after a year?

I made may own 70% limiter for Android. After 5 years the battery was like new. AccuBattery also said it was at 95% capacity.

But scheiße, I had to buy new phone anyway, because banking app refused to work on Android 6.

I’ve always viewed this feature as similar to the plastic covering you sometimes see on old people’s couches. Sure, it makes the thing last longer, but at the expense of being notably worse the entire time you own/use the thing. I’m not crippling my device just to marginally increase its resale value some point down the line.

If the concern isn’t resale/trade-in value, then it makes even less sense because it’s going to be YEARS before your battery life that you’re intentionally throwing away 20% of is going to be less than someone who uses the full capacity but has a slightly more degraded battery.

I’m at 89% health on a 15 Pro after a year of 80% limited charging – which is less than what my 13 Pro ended up with after a year of optimized charging. I wonder if this is due to regular deeper discharges (I often end the day on 5% or less).

Seems like it’s not worth the hassle at all at least for me.

> It's difficult to see when the 80% will ever pay off.

Two words: resale value

Aside from lack of scratch and dent wear, showing a 98% - 100% battery health is very convincing that the phone is "like new".

This gets you back up to the "refurb" price levels instead of the "trade in" price levels from Apple or Gazelle.

It's difficult to see when the 80% will ever pay off. They're a year in and he's got 94% health - but with that limit in place that's an effective battery capacity of 73% (0.94*0.8). At the rate that the others' batteries are degrading it's going to be close to 2 years before they even hit 80% capacity let alone the 60-70% that would make the 80% limited battery have better total real battery time. And at that point what are we saying? You're trading a good chunk of your battery in the first two years of its life for a few percent more several years into owning the phone?

It seems difficult from these numbers to see when, if ever, this choice is going to pay off for the people who opt in.

Does iOS have charge-rate limiting?

I usually only have regular "fast" charge enabled on Android not super fast charge. (10w vs a ~18W on my Samsung S22).

I'm curious how much effect the charge rate limit has. It's not a huge charge rate difference on my phone, 10 vs 18W; I'd imagine higher rate charge devices might benefit more.

Android keeps the battery at 80% for most of the night, only charging it to 100% 1-2 hours before your alarm time. That way, you start the day with a full battery, but it isn't needlessly kept at 100% for an extra 6 hours or so where you almost certainly won't need it.

It's hard to say what contributed most (the charging strategy, more durable batteries, better battery life in general) but battery life has not been a concern at all, even on days with heavy use. Even if I forget/fail to charge in one night, I'm usually OK.

The article says that the author ran out because they were "without a charger for most of the day" - is it normal that a new-ish iPhone, even if charged "only" to 80%, needs to be charged during the day?!?

You'd probably need to get a random sample of a few hundred phones of the same type to get a reliable view of how well the charging limit actually works. It's very likely that the battery health indicator people are seeing on their phones is primarily dictated by how good a battery they got when they initially bought their phones.

AFAIK, these batteries have a tolerance range of around ±5%, so if you just have a sample of two phones, one might end up with 100% battery health after a few hundred cycles and the other with battery health in the low 90s due to no factor other than battery lottery.

Even if you use the 80% limit how you use the device is what really matters, for example if you leave the phone a lot exposed to the sun on your car that will kill the battery fast regardless of how you charge it.

Heat is the main culprit.

I enabled the 80% charge limit from day one (September 2023) and after 159 cycles it is still at 100% maximum capacity.

I think it is also crucial to not allow deep discharge of the battery too frequently. Ideally keep the battery charge in the range of 40-80%. My usage is relatively low so I am mostly within that range.

Infrequently I have charged to 100% for longer days away from home. Enabling low power mode helps to prolong battery life on these occasions too.

They don't say whether the control group is using `Optimised Battery Charging` or `None`. (I assume it's the former.)

Would be interesting to compare all of the three options.

It seems that maybe (for MacRumors staff members?) Optimised Battery Charging already provides most of the benefits of 80% Limit, since the devices are fully charged only for short amounts of time anyway.

I came to pretty much the same conclusions.

My iPhone 15 Pro is at 97% battery health after 287 cycles. My "normal" usage with "optimized charging" will usually result in a phone with 95% - 98% health after a years.

I think the major thing here is number of cycles. I normally charge once per day, at night while sleeping, and with optimized charging i almost never need to charge my phone during the day. With 80% limit enforced i found myself needing to charge late afternoon 2-3 times per week, especially towards the end of the 12 month period.

My point is that i use the same amount of power during a day, regardless of charge limit on the phone, so the number of cycles will be somewhat identical, with the only difference being that with optimized charging i start with 100% battery and plug in around 30%, and with 80% limit i plug in with ~10%, and low SoC (<20%) is almost as bad as high SoC (>80%) for Lithium batteries in EVs, and i doubt it's any different in phones.

I hope it’ll become the default practice for the world’s sake, although I’m not sure the incentives are there - it seems like an EU anti-waste regulation waiting to happen, though.

In my annecdata experience deep discharge (< 5%) and partly charging (like 40 to only 60%) affect the capacity severely. There the annecdata of the OP is not very relevant.

I turned off all the charging optimizations on my day 1 14 Pro and I'm still only at 82% battery health and everything 'seems' fine two years in.

I tried to get my wife to use the feature day one on her new 16 Pro. She turned it off that night. It was going to be too inconvenient to her.

My phones are generally pretty well banged up after 18 months. If the battery lasts that long, I'm happy.

After a year, iPhone 15 - 86 cycles, 100% capacity.

I rarely let it get below 30% and don’t charge to 100%.

I just turned that off immediately. It’s not that expensive to have a shop replace the battery and it will eventually need replacing anyway. I’m not living my life at 80% and milking the battery to avoid something that is inevitable anyway. Glad to see this confirm that it didn’t do a lot anyway.