iOS 18 gives iPhone 15 more charging limit tiers to protect the battery

AppleInsider

Apple has updated its battery health settings in iOS 18 in iPhone 15 by giving more control to users over charging limits.

The new iOS 18 adds more options for a hard charging limit

As introduced in 2023 with iOS 17, the Charging section of Settings on iPhone let users turn on a limit to how much a battery will be charged. The optional limit was 80%, and it meant that in order to extend the lifetime of the battery, it would never charge beyond that limit.

Now in iOS 18, the same setting comes with a range of optional limits. Specifically, users can now set a charge limit of 80%, 85%, 90%, 95%, or 100%.

The 100% limit seems pointless, but there's no on/off toggle for charging limits, so effectively this just means the iPhone should not limit the charging. As AppleInsider pointed out with iOS 17, though, the whole concept is close to pointless -- and it is potentially confusing.

That's because the most that this feature will do is add some weeks to the lifespan of the battery. And in the meantime, every day the phone will have less charge than it should.

The confusion, too, is because this is not the same as the iPhone's Optimized Battery Charging setting. This is in the same Charging settings section and the two options are related.

What Optimized Battery Charging does by default is stop the iPhone charging once it reaches 80% -- but then lets it continue to 100% just in time for when the owner typically wakes up and starts using it.

Under iOS 18, the hard charging limit is set by default to 100%, and if a lower limit is set, then Optimized Battery Charging turns off. It cannot be turned back on unless the hard limit is returned to 100%.

There is one more option in iOS 18's new system. Should a user choose to lower the limit from 100%, but then return it to that maximum, they are prompted to confirm that they want to do so.

Plus the new prompt allows the user to say they want a 100% limit only until tomorrow. After that, it will revert to whatever limit they previously had.

AppleInsider recommends that users ignore this new charging limit setting and instead stick with just the Optimized Battery Charging. The benefits in the long term are fractional and perhaps non-existent, where in the short term this makes it more likely that a user will need to top up the charge during the day.



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Xed

I wish they'd allow this in macOS. I use a 3rd party app to maintain my Mac's battery health.

40domi

I use the 80% battery charge limit and I like it, the only thing missing is the battery optimisation, I often wake up and the battery is less than 80% if the alarm has gone off a few times, I wish Apple would sort that out pronto, as there is no technical reason, why they can't do it.
The 85% will probably be my limit.
I strongly disagree with the writer of this article, when he says it will only add a few weeks to the life of the battery, my iPhone 13 Pro had 100% battery health for 2 years whilst I had it, simply due to the fact, I never let it run below 60% before charging and it was never charged over night.
Now with Stand By, I don't have that luxury, so we'll see how the 80% charging will look like after 2 years?

appleinsideruser

Yes, I too disagree with the author. It’s another William wobble. Use the feature if your day-to-day usage doesn’t challenge your battery capacity. Then on the special occasions that you need the capacity, it will be there!

As others are keen to say, you don’t need to use these optional features. But saying avoid using this is unhelpful.

Better yet, Apple should enable this feature on earlier phones. My 14 Pro can put its charging on hold for hours (maintaining 80%) when using continuity camera. It’s not a hardware limitation.

elijahg

appleinsideruser said:

Better yet, Apple should enable this feature on earlier phones. My 14 Pro can put its charging on hold for hours (maintaining 80%) when using continuity camera. It’s not a hardware limitation.

Apple seems to have gone really hard on limiting new features to the latest iPhone in iOS 18.

timpetus

Use this feature, as long as you are near a charger. Turn it off when you'll be away from power for an extended time. Use the 80% setting - it's better. My 15 Pro has had it turned on since day one back in September 2023 and still has 100% battery health with nearly 250 cycles.

watto_cobra

My 14ProMax went 15 months before dropping to 99% capacity. 

Because it misses out on the 80% charge limiter feature of the 15Pro, I made a Siri Shortcut that turns off the smart outlet it’s charger is connected to when it reaches 80% charged. I wake up with my phone at 80% every morning 

heddy

the whole concept is close to pointless

That's because the most that this feature will do is add some weeks to the lifespan of the battery. And in the meantime, every day the phone will have less charge than it should.

I had to make an account to point out that the author is horribly incorrect here. It's a known fact that charging lithium-ion batteries to 80 or 90 percent is massively beneficial for the battery (Source: Battery University, Apple, every electric car manufacturer, every battery engineer). The highest non-damaging voltage for lithium-ion is around 3.96 volts, but charging to 100% results in 4.4 volts for the typical Apple battery, which damages the battery health fast and drives people to replace phones fast, which is very wasteful. Lower max charge level = lower max voltage = longer lifespan, and better performance during the lifespan. Higher voltages are exponentially more damaging, so even a small reduction in max charge level can have massive benefits.

If you truly need every single percent, then sure, don't use this setting, because this setting isn't for you. But for many people, this setting is amazing. We can use this setting for most days, thus preserving the battery health, then we can turn off this setting and charge to 100% for when we truly need the full capability, like a vacation or trip where we won't have access to charging. And that way, 100% will actually be 100% because the battery won't be as damaged as it would be if we had charged it to 100% every single day.

If preserving battery health, less need for battery replacements, and the battery working amazingly on the few days the full battery is actually needed doesn't sound great to you... then this is not for you! But don't spread uninformed messages like "oh this is useless... oh this is confusing... oh this only adds a few weeks of lifespan." It has a clear and easy to understand purpose. The lower your max charge level, the exponentially longer the battery lifespan. Even capping the charge at 90% for your non-busy days and un-capping back to 100% on busy days will have a great impact on battery health. If you charge to 100% every day, you are not actually getting 100% capacity because your battery will be so damaged it will start losing capacity in a matter of weeks of use. Meanwhile, people who use the cap will stay at 100% battery health for quite a while, and when their battery health starts to drop, it will drop very slowly!

In addition to what engineers say, I know from personal experience that a lower charge cap adds years of useful life. Years, not weeks. My 3-year-old iPhone is at 96% battery health, whereas it would surely be at 70% health or worse if I had charged it to 100% every single day. I used an automated notification, to alert me of charge level 80% or 90% being reached so I could pull the plug when I wanted. Apple adding a setting is a huge improvement, because I will no longer need the alert or manually stopping the charge. There's a reason Apple adds this setting... it's because their engineers know it works. I'm sure Apple would love for people to keep charging to 100% every single day to increase sales of replacement batteries, so I applaud Apple for adding this setting.

A different setting - the "optimization" setting that reduces the time the battery spends at 100% by charging right before you wake up - is good for batteries because it reduces time spent at the highly damaging 4.4 volts. Of course, not spending any time at that voltage is even better, so I truly appreciate Apple for adding the option to cap the charge level.

Fact: the lithium-ion industry standard max voltage is 4.2 volts, and the nominal voltage is 3.7 volts. And yet Apple and the entire smartphone industry pushed the max voltage to 4.4 volts and pushed the nominal voltage to 3.8 volts. Apple's engineers say they used better materials to support the increased voltage, but materials can only do so much... Apple's (and all smartphone makers, to be fair) use of higher-than-industry-standard voltages are one reason why their batteries only perform well for 1 to 2 years, when previously lithium-ion batteries would perform well for 3 to 7 years.

appleinsideruser

heddy said:

the whole concept is close to pointless

That's because the most that this feature will do is add some weeks to the lifespan of the battery. And in the meantime, every day the phone will have less charge than it should.

I had to make an account to point out that the author is horribly incorrect here. It's a known fact that charging lithium-ion batteries to 80 or 90 percent is massively beneficial for the battery (Source: Battery University, Apple, every electric car manufacturer, every battery engineer). The highest non-damaging voltage for lithium-ion is around 3.96 volts, but charging to 100% results in 4.4 volts for the typical Apple battery, which damages the battery health fast and drives people to replace phones fast, which is very wasteful. Lower max charge level = lower max voltage = longer lifespan, and better performance during the lifespan. Higher voltages are exponentially more damaging, so even a small reduction in max charge level can have massive benefits.

If you truly need every single percent, then sure, don't use this setting, because this setting isn't for you. But for many people, this setting is amazing. We can use this setting for most days, thus preserving the battery health, then we can turn off this setting and charge to 100% for when we truly need the full capability, like a vacation or trip where we won't have access to charging. And that way, 100% will actually be 100% because the battery won't be as damaged as it would be if we had charged it to 100% every single day.

If preserving battery health, less need for battery replacements, and the battery working amazingly on the few days the full battery is actually needed doesn't sound great to you... then this is not for you! But don't spread uninformed messages like "oh this is useless... oh this is confusing... oh this only adds a few weeks of lifespan." It has a clear and easy to understand purpose. The lower your max charge level, the exponentially longer the battery lifespan. Even capping the charge at 90% for your non-busy days and un-capping back to 100% on busy days will have a great impact on battery health. If you charge to 100% every day, you are not actually getting 100% capacity because your battery will be so damaged it will start losing capacity in a matter of weeks of use. Meanwhile, people who use the cap will stay at 100% battery health for quite a while, and when their battery health starts to drop, it will drop very slowly!

In addition to what engineers say, I know from personal experience that a lower charge cap adds years of useful life. Years, not weeks. My 3-year-old iPhone is at 96% battery health, whereas it would surely be at 70% health or worse if I had charged it to 100% every single day. I used an automated notification, to alert me of charge level 80% or 90% being reached so I could pull the plug when I wanted. Apple adding a setting is a huge improvement, because I will no longer need the alert or manually stopping the charge. There's a reason Apple adds this setting... it's because their engineers know it works. I'm sure Apple would love for people to keep charging to 100% every single day to increase sales of replacement batteries, so I applaud Apple for adding this setting.

A different setting - the "optimization" setting that reduces the time the battery spends at 100% by charging right before you wake up - is good for batteries because it reduces time spent at the highly damaging 4.4 volts. Of course, not spending any time at that voltage is even better, so I truly appreciate Apple for adding the option to cap the charge level.

Fact: the lithium-ion industry standard max voltage is 4.2 volts, and the nominal voltage is 3.7 volts. And yet Apple and the entire smartphone industry pushed the max voltage to 4.4 volts and pushed the nominal voltage to 3.8 volts. Apple's engineers say they used better materials to support the increased voltage, but materials can only do so much... Apple's (and all smartphone makers, to be fair) use of higher-than-industry-standard voltages are one reason why their batteries only perform well for 1 to 2 years, when previously lithium-ion batteries would perform well for 3 to 7 years.

Great points! If only Apple would add the feature to older phones too. The hardware (certainly in my 14 Pro) can hold charge at 80%.