iPhone 15 has new battery health controls to prevent charging past 80%

Posted:
in iPhone
iPhone 15 users looking to prolong their battery health a little further have a new option -- an 80% charging hard limit.

iPhone 14 Pro Max at 100%
iPhone 14 Pro Max at 100%

People concerned over
iPhone battery health attempt to control every aspect of their device experience to eke out moments of additional usage. While AppleInsider recommends users just let the battery power management system handle things, Apple is adding a new toggle.

New information obtained by MacRumors' Joe Rossignol during a Verge Q&A session confirm the entire iPhone 15 lineup has a new battery health setting. Users can choose to stop the iPhone from charging past 80% rather than reaching 100%.

This isn't the usual Optimized Battery Charging setting that stops the iPhone from charging once it hits 80%, then resumes charging to 100% to finish just before the user wakes up. Instead, the iPhone will never charge past 80%.

Charging a battery is relatively efficient and uniform from 0% to 80%, but that last 20% generally takes more energy and produces more heat. This leads some users to consciously try to float their battery between 40% and 80% at all times to prolong battery health.

Now, users no longer need to monitor charging and can have it stop at 80% automatically. However, AppleInsider continues to recommend users stick with Optimized Battery Charging and avoid this new setting.

There is very little to gain from stopping an iPhone from charging past 80%. Instead, the user will suffer from not having access to the full potential of the battery capacity while only salvaging a few more weeks of battery health.

Instead, users should continue to use their devices with fully automatic settings and charge whenever necessary. There's no stopping physics, and all batteries will need to be replaced eventually.

Read on AppleInsider
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Comments

  • Reply 1 of 23
    elijahgelijahg Posts: 2,770member
    Actually... Most wear to lithium batteries is in the topping charge (80%+). Preventing the battery exceeding 80% does genuinely increase battery lifetime quite significantly. If a user doesn't discharge their battery to <20% by the end of the day, there is no point in charging it to 100% and causing more wear. Better to use the lower 0-80% than the upper 20-100%. This is why Apple limits the charge to 80% as much as possible at night, which is a relatively small proportion of time, but the battery improvement is enough that they deem it worth it.

    I hope this comes to older iPhones too.
    Alex1NmaltzbyronlappleinsideruserFileMakerFellerjony0
  • Reply 2 of 23
    OferOfer Posts: 246unconfirmed, member
    I wonder why they don’t give you the ability to do this with pre-15 phones. Seems like a simple software thing that wouldn’t be hardware dependent.
    mattinozbyronlzimmermannkdupuis77williamlondoncanukstormappleinsideruserwatto_cobrajony0
  • Reply 3 of 23
    elijahg said:
    Actually... Most wear to lithium batteries is in the topping charge (80%+). Preventing the battery exceeding 80% does genuinely increase battery lifetime quite significantly. If a user doesn't discharge their battery to <20% by the end of the day, there is no point in charging it to 100% and causing more wear. Better to use the lower 0-80% than the upper 20-100%. This is why Apple limits the charge to 80% as much as possible at night, which is a relatively small proportion of time, but the battery improvement is enough that they deem it worth it.

    I hope this comes to older iPhones too.
    Yep, keeping the battery from fully charging increases both service life and overall energy delivered (from https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries). This data is from charging at constant 20°C temperature; the increased battery temperature when charging phones likely further exacerbates capacity loss, especially when rapid charging with high current.
    thtkempathonnodgebyronlFileMakerFellerwatto_cobrajony0
  • Reply 4 of 23
    So, now it’s bad to charge your phone to 100% ?  Lol,  so much different information out there.  It’s hard to know what to believe. 
    edited September 2023 watto_cobra
  • Reply 5 of 23
    Wesley HilliardWesley Hilliard Posts: 205member, administrator, moderator, editor
    M68000 said:
    So, now it’s bad to charge your phone to 100% ?  Lol,  so much different information out there.  It’s hard to know what to believe. 
    Simple: ignore randombro69 on a forum and listen to the experts. We've detailed what you should and shouldn't do for iPhone battery health. My recommendation will always be "don't worry about it."

    Really. This whole thing is getting silly. You can't beat physics.

    And I would understand all the drama if battery replacements weren't readily available and cheap.
    Alex_Vdewmewatto_cobraStrangeDaysjony0
  • Reply 6 of 23
    mr. hmr. h Posts: 4,870member
    M68000 said:
    So, now it’s bad to charge your phone to 100% ?  Lol,  so much different information out there.  It’s hard to know what to believe. 
    Simple: ignore randombro69 on a forum and listen to the experts. We've detailed what you should and shouldn't do for iPhone battery health. My recommendation will always be "don't worry about it."

    Really. This whole thing is getting silly. You can't beat physics.

    And I would understand all the drama if battery replacements weren't readily available and cheap.
    Who’s the expert here? You? Because your article is dead wrong. It has long been well established that charging lithium ion batteries beyond 80% accelerates the aging process. It’s not the charging per se; rather just being at that elevated state of charge. That’s why the optimised charging mode attempts to wait until the last moment to bring the battery to 100%: the theory is you will start using the phone soon after it reaches 100%, thus minimising the time the battery spends above 80%. However, in my experience the optimised charging is easily thrown off if the user has an inconsistent routine so I welcome this additional control provided by Apple.
    byronlcitpekswilliamlondonbaconstanggrandact73FileMakerFellerelijahgwatto_cobrajony0
  • Reply 7 of 23

    Charging a battery is relatively efficient and uniform from 0% to 80%, but that last 20% generally takes more energy and produces more heat. This leads some users to consciously try to float their battery between 40% and 80% at all times to prolong battery health.

    Now, users no longer need to monitor charging and can have it stop at 80% automatically. However, AppleInsider continues to recommend users stick with Optimized Battery Charging and avoid this new setting.

    There is very little to gain from stopping an iPhone from charging past 80%. Instead, the user will suffer from not having access to the full potential of the battery capacity while only salvaging a few more weeks of battery health.

    Instead, users should continue to use their devices with fully automatic settings and charge whenever necessary. There's no stopping physics, and all batteries will need to be replaced eventually.

    Yikes.  Someone needs to familiarize themselves with the CC/CV charging algorithm, used in lithium battery charging.

    How can the last CV saturation stage take "more energy" and produce "more heat" when the current is being tapered down until the cell reaches termination voltage?  Especially compared to the initial bulk stage, where full current is applied at the maximum C rate (if wise, within the recommended guidelines given by the cell manufacturer)?

    As for the thought that one should never venture above 80% SoC, that's very conservative, and doesn't take into account the practical considerations most users will have.

    Ideally, lithium batteries should be kept within 20-80% SoC to help prolong durability, which is true, but most users aren't going to sacrifice 40% of capacity to have their battery last an unspecified, variable, and not guaranteed additional term.  They'd rather just use their devices and get the most out of them in practical, immediate life.

    These are disposable consumer devices with finite lives and support terms.  They're not designed to be used or kept for eternity.  When a cell does wear out, Apple will happily take your money and perform a replacement.  Or the user may opt to simply replace the device.  Life goes on.

    In this regard, "don't worry about it," and "just use your device/get on with it" is probably the path most will take, and most sensible.  If one must worry about something, try to eat a healthy diet and get some exercise, to live a longer life.  That may pay much greater dividends, and even then, there are no guarantees.

    But I am glad that Apple recognized that their Optimized Charging feature was too convoluted, and relied upon behaviors and usage patterns some users never followed, which worse of all, could render it ineffective, and has now given users a clear cut, manual option.
    mr. hdewmemuthuk_vanalingamJanNLFileMakerFellerwatto_cobrajony0
  • Reply 8 of 23
    I would like this feature to be available on my iPhone 14.  It’s just software isn’t it?
    Ofercanukstormappleinsideruserwatto_cobra
  • Reply 9 of 23
    mr. h said:
    M68000 said:
    So, now it’s bad to charge your phone to 100% ?  Lol,  so much different information out there.  It’s hard to know what to believe. 
    Simple: ignore randombro69 on a forum and listen to the experts. We've detailed what you should and shouldn't do for iPhone battery health. My recommendation will always be "don't worry about it."

    Really. This whole thing is getting silly. You can't beat physics.

    And I would understand all the drama if battery replacements weren't readily available and cheap.
    Who’s the expert here? You? Because your article is dead wrong. It has long been well established that charging lithium ion batteries beyond 80% accelerates the aging process. It’s not the charging per se; rather just being at that elevated state of charge. That’s why the optimised charging mode attempts to wait until the last moment to bring the battery to 100%: the theory is you will start using the phone soon after it reaches 100%, thus minimising the time the battery spends above 80%. However, in my experience the optimised charging is easily thrown off if the user has an inconsistent routine so I welcome this additional control provided by Apple.
    I used to try to point this out in this forum, pointing out scientific sources to this source, but every time one of the site writers came here (probably the one from this article) and always claimed it was wrong, that it made no difference, etc. To him it doesn't matter that there are all these scientific papers; Apple itself ships devices half-charged; that it offered optimized battery charging; that it now offers this setting; that Apple offers a charge management feature since iOS 11 or 12, which detect when a device is connected to power all the time (like a kiosk) and automatically caps charging at 80%; that Samsung offers this setting as well; that RC battery chargers make the express same recommendation (and usually have a "storage mode" setting); that Tesla offers similar settings and guidance (avoid charging to 100% unless absolutely necessary) on their EVs; that e-bikes/e-scooters do the same thing; and so on and so forth. No, none of this matters, after all he's a "nuclear power electrician" and we should just believe that somehow makes him an expert on the completely distinct field of battery lifespan management. Really, the writing of the current article in particular shows how desperate he is getting: "yes, Apple added a setting; trust us, you shouldn't use it, you'll gain a few weeks". Which is false, with proper charge and heat management you can, very conservatively speaking, double the lifespan of your batteries.

    Now onto some of the facts:
    1. Some of us don't need, on a daily basis, the full 100% charge the phone provides. We have actual work to do and cell phones are generally just toys and, in an emergency, very poor replacements for an actual work machine like a Mac or PC. Or we always have a charger close by and could in practice keep the phone charging 95% of the time, and have no "range anxiety". I for one welcome this setting with open arms.
    2. With regards to point 1, if people were to keep their phones charged 95% of the time at 100%, this would have definite effects on battery lifespan. On the other hand, with this setting, batteries could last much much longer.
    3. When we do need the full charge, we can just toggle off the setting temporarily. Best of both worlds.
    4. Heat is the #1 killer of batteries, especially combined with high state-of-charge. You have people who spend most of their day in a car, sometimes with the phone in direct sunlight, and charging to 100% all the time. I'm impressed that under such conditions a phone's battery would last a year. Now change that to charging to 80%, and suddenly the battery has a decent chance of lasting years.

    Now onto the next fallacy: "just replace the battery, it's cheap". Here's a few other facts:

    1. The world is not America. Where I live, changing an iPhone battery costs a significant portion of a month's minimum wage. I of course make more than the minimum wage, but it is proportionately expensive to myself. And pray you have an Apple store or an Apple authorized repair shop where you live; I live in a city of ~500,000 people and there wasn't one here until a few years ago. In my whole country, one of the largest on earth, with over 200 million people, there are only 2 Apple stores. 90% of the country is hundreds of miles away from the nearest Apple store. In fact a large percentage of the country is over 1,000 miles away from the nearest Apple store.
    2. This leads people (even in America) to change batteries on unauthorized resellers in these phone-fixing kiosks you now find everywhere. Since Apple doesn't sell the batteries they use to the public (including these kiosks), you're taking a gamble on the lowest-bidder type battery, with awful performance and even risk of swelling and explosion.
    3. Apple loves to claim how they're eco-friendly and so on. Well guess what's better than recycling a battery? Not swapping a battery at all! But of course in that case there's no money to be made swapping the battery or, even more convenient to Apple, swapping the device as a whole for a brand new iPhone.
    4. To finish off, Apple may just plain refuse to swap the battery for you. I have a personal experience with this, on a 10.5" iPad Pro. The battery has been severely degraded, both as indicated by Coconut Battery, and from monitoring runtimes (much, much less than when it was new). I was in Abu Dhabi this year and took it to the Apple store in Yas Mall, asking them to change the battery for the price quoted on the website (459 AED, about US$ 125). Their reply, later confirmed by a call to the UAE Apple call center: "it's impossible to change the battery on an iPad, so we have to change the whole device and we charge much more [over 1200 AED as I recall] -- unless our [opaque] diagnostics claim that it reached the magical <80% threshold, in which case we'll replace it for 459 AED". Well now they run this opaque diagnostic and voilà, like magic, it claims my battery is at 90%, which disagrees with both Coconut Battery (which claimed <70%) and my actual experience. For all I know this opaque diagnostic software just outputs a random number over 85% to ensure they never agree to letting you pay the 459 AED price. Never mind that this information isn't given on this page or anywhere else. So you buy an iPad, safe in the knowledge that whenever you're not happy with how long a charge lasts, you can just pay 459 AED to replace it. Then when you go exercise this "right" you thought you had, suddenly it's 1200 AED price. Really slimy tactics from Apple.
    5. By the way, a battery for the 10.5" iPad Pro costs US$ 25 at iFixIt. I'm pretty sure they sell decent batteries, although I'd rather have the Apple original one. And that's retail price, from a company that buys them in small quantities -- compare to Apple buying at gargantuan quantities with tailormade purchase contracts. So it's pretty clear that Apple is making a decent amount of cash on these battery replacements. And also, the claim by the Apple store that "it's impossible to replace the iPad battery" is blatantly false: iFixIt has a guide showing how to do it, and I've asked many of these phone-fixing kiosks and they will swap it if I want. In the end I just went with a new iPad (see, Apple's strategy of planned obsolescence worked perfectly with me) and will sell the old one to someone who will just swap it for a lowest-bidder battery and risk setting fire to their house. Oh well, at least it's their house, not mine.
    mr. hmuthuk_vanalingamMplsPbaconstangFileMakerFellerelijahgwatto_cobra
  • Reply 10 of 23
    Not debating 80% charging lengthens phone's battery longevity because science dictates truth. My argument is make battery replacement easier and safer. In past, I have DIY replaced battery twice on iPhone 6S but last time when I replaced on iPhone 8, it went into continuous boot loop and the iPhone 8 became bricked. My current iPhone is 13 Pro but I keep unlocked older touchid iPhone with SIM tray for overseas use.

    My point is make battery on any phone easily replaceable, reasonably priced. and why I don't see 80% charge selection on IOS 17 installed on pre iPhone 15 ?
    edited September 2023 muthuk_vanalingamOferwatto_cobra
  • Reply 11 of 23
    dewmedewme Posts: 5,413member
    citpeks said:

    Charging a battery is relatively efficient and uniform from 0% to 80%, but that last 20% generally takes more energy and produces more heat. This leads some users to consciously try to float their battery between 40% and 80% at all times to prolong battery health.

    Now, users no longer need to monitor charging and can have it stop at 80% automatically. However, AppleInsider continues to recommend users stick with Optimized Battery Charging and avoid this new setting.

    There is very little to gain from stopping an iPhone from charging past 80%. Instead, the user will suffer from not having access to the full potential of the battery capacity while only salvaging a few more weeks of battery health.

    Instead, users should continue to use their devices with fully automatic settings and charge whenever necessary. There's no stopping physics, and all batteries will need to be replaced eventually.

    Yikes.  Someone needs to familiarize themselves with the CC/CV charging algorithm, used in lithium battery charging.

    How can the last CV saturation stage take "more energy" and produce "more heat" when the current is being tapered down until the cell reaches termination voltage?  Especially compared to the initial bulk stage, where full current is applied at the maximum C rate (if wise, within the recommended guidelines given by the cell manufacturer)?

    As for the thought that one should never venture above 80% SoC, that's very conservative, and doesn't take into account the practical considerations most users will have.

    Ideally, lithium batteries should be kept within 20-80% SoC to help prolong durability, which is true, but most users aren't going to sacrifice 40% of capacity to have their battery last an unspecified, variable, and not guaranteed additional term.  They'd rather just use their devices and get the most out of them in practical, immediate life.

    These are disposable consumer devices with finite lives and support terms.  They're not designed to be used or kept for eternity.  When a cell does wear out, Apple will happily take your money and perform a replacement.  Or the user may opt to simply replace the device.  Life goes on.

    In this regard, "don't worry about it," and "just use your device/get on with it" is probably the path most will take, and most sensible.  If one must worry about something, try to eat a healthy diet and get some exercise, to live a longer life.  That may pay much greater dividends, and even then, there are no guarantees.

    But I am glad that Apple recognized that their Optimized Charging feature was too convoluted, and relied upon behaviors and usage patterns some users never followed, which worse of all, could render it ineffective, and has now given users a clear cut, manual option.
    This sounds like … sound advice, even though you are kind of advocating for the “don’t worry about it” option, which I subscribe to. It sounds like Apple’s Optimized Charging feature is actually providing a false sense of comfort when, in fact, it probably provides very little to no benefit in practice. The 20-80 hard-limit option, while not necessarily the best option for people who don’t adhere to the concept of the user catering to the needs of the device, rather than the device catering to the needs of the user, no matter the consequences, is at least a proven strategy for extending battery life in some cases. This absolutely makes sense. If you’re willing to jump through hoops to increase the probability that you can extend your device’s battery life, you may as well follow a process that has a higher likelihood of working. Accepting a reduced , even when it’s enforced automatically, is still jumping through a hoop.

    I may be in the minority, but I’ve yet to have an Apple device of any sort run the battery down at a rate that led to what I considered premature loss of the use of the device. I am getting close with my Apple Watch Series 5 because its battery health is now at 81%. When it goes below 80% I will shell out the $99 USD for a battery replacement because the watch is otherwise impeccable. Part of me would like to use the need for a replacement battery as an excuse to purchase a brand new Apple Watch Ultra 2. 

    That said, I have lost a handful of devices (3 iPods, 1 iPad mini, 2 iPhones, and 1 third party storage device with built-in battery backup) to battery bloat even when the battery health was still showing a high level of health, at least in the devices that provided battery health indicators, or no noticeable loss in battery run time. I also lost an iPhone 11 to sudden and unrecoverable death shortly after its AppleCare expired. All attempts to resuscitate the iPhone 11 by me and Apple Geniuses failed. Totally bricked with no signs of life.

    Could some or all of these device deaths have been prevented by following the 80-20 charging rule? I don’t know. None of them exhibited a loss in battery capacity over time as my Apple Watch has shown. The batteries simply expanded beyond the volume of their chassis. In the cases of the iPods, iPhones, and iPad mini the first warning indication was the device case looking like it had popped off on one side. When I removed the case, the screen popped out even further. The protective cases were actually keeping the screen somewhat attached to the device’s body.

    Does non-optimal charging contribute to battery bloat? If it increases heat I can see where there may be a connection. I happen to believe that some super thin devices like the later iPod Touches and iPhones after iPhone 4/4s with ultra thin profiles are more prone to battery bloat failure. Some of the newer batteries also seem more bloat prone. I still have an iPod 2, iPod 4, iPad 2, iPhone 4s, and 2011 MacBook Air that are still running (slowly and with ancient software and OS versions) but show no signs of battery bloat related failure. 
    edited September 2023 watto_cobra
  • Reply 12 of 23
    dewmedewme Posts: 5,413member
    I just want to mention one thing regarding the “you cannot ignore the science” arguments.

    I totally agree that you cannot ignore the science. But there is a difference between science and engineering. Engineered products are built with as much consideration for the human and societal element as they are for science. Engineers are responsible for designing products that manage the limitations imposed by the science so as not to expose users to unnecessary harm or inconvenience. This is part of what’s considered engineering margins or operational derating. 

    Engineering margin is used to increase the likelihood that a product is not designed with its normal operating or rated limits too close to its scientific and physical limits. For example, if an elevator is user rated for 1000 lbs maximum, the engineers who build it and specify its operational limits will include sufficient margin to allow the elevator to exceed its rated limits by some percentage to reduce the likelihood that an overloaded elevator will suffer total failure. Additionally, a well engineered elevator will include safety devices to ensure that users cannot overload the elevator to the point of failure. 

    If the batteries in these devices are in some way harmed or degraded when the user is utilizing the device within its normal, rated, and advertised limits there is an engineering design deficiency with the product. This is especially true if the user is expected to manually enforce limits/margins on their own that result in a loss in performance, capacity, or product lifetime over what the product builder sold to the customer.

    If maintaining the battery charge between 20-80 percent is imperative to the health of the product then Apple should enforce these limits through derating the battery capacity and runtime that it advertises pre-sales and what it shows on the device. In this case, the percentage of battery charge remaining should reflect the amount of usable and battery-safe battery capacity available to the user based on the derated values and margins engineered into the product. This type of engineering driven product design is not beyond the capability of Apple’s product designers.

    So this isn’t simply an argument about science or best practices. It’s an argument about engineered product design that considers the impact that battery rating and management has on the useful lifetime of the product. Some people may argue that enforcing engineering margins hides potential value because the batteries can actually be “pushed beyond their practical limits” when absolutely necessary, perhaps for emergency situations. I can see where an accommodation could be included to place the device into a temporary “Emergency Mode” with appropriate warnings.

    In any case, I think that what Apple has done with providing the 20-80 limit is a crude admission that they didn’t do the engineering that they should have done to relieve their customers from having to worry about something they shouldn’t have to worry about. After all, not all users are scientists, they’re just ordinary folks using a product they expect to “just work.” It’s the engineers that are responsible for making that happen.
    edited September 2023 muthuk_vanalingamFileMakerFeller
  • Reply 13 of 23
    dewme said:
    I just want to mention one thing regarding the “you cannot ignore the science” arguments.

    I totally agree that you cannot ignore the science. But there is a difference between science and engineering. Engineered products are built with as much consideration for the human and societal element as they are for science. Engineers are responsible for designing products that manage the limitations imposed by the science so as not to expose users to unnecessary harm or inconvenience. This is part of what’s considered engineering margins or operational derating. 

    Engineering margin is used to increase the likelihood that a product is not designed with its normal operating or rated limits too close to its scientific and physical limits. For example, if an elevator is user rated for 1000 lbs maximum, the engineers who build it and specify its operational limits will include sufficient margin to allow the elevator to exceed its rated limits by some percentage to reduce the likelihood that an overloaded elevator will suffer total failure. Additionally, a well engineered elevator will include safety devices to ensure that users cannot overload the elevator to the point of failure. 

    If the batteries in these devices are in some way harmed or degraded when the user is utilizing the device within its normal, rated, and advertised limits there is an engineering design deficiency with the product. This is especially true if the user is expected to manually enforce limits/margins on their own that result in a loss in performance, capacity, or product lifetime over what the product builder sold to the customer.

    If maintaining the battery charge between 20-80 percent is imperative to the health of the product then Apple should enforce these limits through derating the battery capacity and runtime that it advertises pre-sales and what it shows on the device. In this case, the percentage of battery charge remaining should reflect the amount of usable and battery-safe battery capacity available to the user based on the derated values and margins engineered into the product. This type of engineering driven product design is not beyond the capability of Apple’s product designers.

    So this isn’t simply an argument about science or best practices. It’s an argument about engineered product design that considers the impact that battery rating and management has on the useful lifetime of the product. Some people may argue that enforcing engineering margins hides potential value because the batteries can actually be “pushed beyond their practical limits” when absolutely necessary, perhaps for emergency situations. I can see where an accommodation could be included to place the device into a temporary “Emergency Mode” with appropriate warnings.

    In any case, I think that what Apple has done with providing the 20-80 limit is a crude admission that they didn’t do the engineering that they should have done to relieve their customers from having to worry about something they shouldn’t have to worry about. After all, not all users are scientists, they’re just ordinary folks using a product they expect to “just work.” It’s the engineers that are responsible for making that happen.
    The problem is that you cannot look only at the science and engineering aspects, but also sales and marketing.

    The fact is that mobile phone buyers want phones that are thin, lightweight, powerful, cheap and that hold a charge all day or even more (and when they do have to charge, they would like to fully charge it in a few minutes, not hours). And unfortunately the technology isn't there to meet all of these constraints simultaneously and comfortably. Battery technology even more so, which isn't exclusive to mobile phones or even portable electronic devices in general: just have a look at EVs.

    Then there's the fact that battery runtime is a (strong) selling point, whereas very few people factor battery lifespan into the purchase. Combine this with the relationship between "overcharging" batteries and their reduced lifespan -- and really, there is no law of nature saying you have to stop charging at 4.2 V or 4.3 V or 4.35 V, all you have are different charge limit/lifespan tradeoffs. This translates into perverse incentives for device designers, who push batteries to the limit even if it means they will last a year or two (and some users don't even care since they upgrade their devices every year).

    Oh, and with the drive to ever thinner devices, and users wanting waterproof phones (again a selling point), now you have to make batteries non-user-serviceable. Prior to this you would just buy a new battery for cheap and replace it. Or even keep a battery in a bag, and if you ran out of juice, you'd just replace it. Now this is impossible, and swapping batteries is much more expensive due to the labor required to take apart the phone and put it together again, much more so than the cost of batteries themselves.

    So really, what was Apple supposed to do? Say they cap their batteries at the "ideal" 3.9 V (~60% of the capacity of a battery charged to 4.2 V), turning off the device once it reached the equivalent of ~30% state of charge, and remove any fast charging capabilities; this would lengthen battery lifespan considerably. But then their Chinese competitors would advertise phones with similar thickness and weight, which would last 3 times longer on a charge, and with fast-charging. Sure their batteries would last a year, two at most, but more power to them: the user would just buy a new one, providing extra revenue for the manufacturer. So Apple does what's reasonable, and just goes along with what everyone else does, which is what you would call bad design. Thankfully they've finally been waking up to this issue and adding features such as charge management, optimized battery charging and now this toggle. Of course none of this would have been an issue if they just let the owner of the phone use it as they see fit rather than according to the rules that Apple dictates; i.e. App Store rules won't let you have an app similar to Al Dente in the iPhone.
    retrogustomr. hFileMakerFellerelijahg
  • Reply 14 of 23
    A few years ago I wrote to Apple to ask for something similar for laptops. I mostly buy laptops, but 99% of the time I use them at home plugged in, and on occasion I use them elsewhere, but almost never far from an outlet. So I basically always use them plugged in, and like to just leave them plugged in rather than unplugging them every time I turn them off, but as a result my batteries periodically swell up and need to be replaced. I think it’s happened 4 times over the years. One Apple Store employee told me their laptops “weren’t designed to be left plugged in,” although they obviously were left plugged in at the Apple Store. With a previous model, I eventually just took out the battery and used it without one, although it’s nice to have battery backup for emergencies, and these days removing the battery is not as easy. What I asked for was a “desk mode” that would just maintain the battery at a modest level without charging frequently, and if I knew I was going to need more of a charge I could just switch out of desk mode ahead of time. Maybe someday…
    FileMakerFellerwatto_cobra
  • Reply 15 of 23
    dewmedewme Posts: 5,413member
    swineone said:
    dewme said:
    I just want to mention one thing regarding the “you cannot ignore the science” arguments.

    I totally agree that you cannot ignore the science. But there is a difference between science and engineering. Engineered products are built with as much consideration for the human and societal element as they are for science. Engineers are responsible for designing products that manage the limitations imposed by the science so as not to expose users to unnecessary harm or inconvenience. This is part of what’s considered engineering margins or operational derating. 

    Engineering margin is used to increase the likelihood that a product is not designed with its normal operating or rated limits too close to its scientific and physical limits. For example, if an elevator is user rated for 1000 lbs maximum, the engineers who build it and specify its operational limits will include sufficient margin to allow the elevator to exceed its rated limits by some percentage to reduce the likelihood that an overloaded elevator will suffer total failure. Additionally, a well engineered elevator will include safety devices to ensure that users cannot overload the elevator to the point of failure. 

    If the batteries in these devices are in some way harmed or degraded when the user is utilizing the device within its normal, rated, and advertised limits there is an engineering design deficiency with the product. This is especially true if the user is expected to manually enforce limits/margins on their own that result in a loss in performance, capacity, or product lifetime over what the product builder sold to the customer.

    If maintaining the battery charge between 20-80 percent is imperative to the health of the product then Apple should enforce these limits through derating the battery capacity and runtime that it advertises pre-sales and what it shows on the device. In this case, the percentage of battery charge remaining should reflect the amount of usable and battery-safe battery capacity available to the user based on the derated values and margins engineered into the product. This type of engineering driven product design is not beyond the capability of Apple’s product designers.

    So this isn’t simply an argument about science or best practices. It’s an argument about engineered product design that considers the impact that battery rating and management has on the useful lifetime of the product. Some people may argue that enforcing engineering margins hides potential value because the batteries can actually be “pushed beyond their practical limits” when absolutely necessary, perhaps for emergency situations. I can see where an accommodation could be included to place the device into a temporary “Emergency Mode” with appropriate warnings.

    In any case, I think that what Apple has done with providing the 20-80 limit is a crude admission that they didn’t do the engineering that they should have done to relieve their customers from having to worry about something they shouldn’t have to worry about. After all, not all users are scientists, they’re just ordinary folks using a product they expect to “just work.” It’s the engineers that are responsible for making that happen.
    The problem is that you cannot look only at the science and engineering aspects, but also sales and marketing.

    The fact is that mobile phone buyers want phones that are thin, lightweight, powerful, cheap and that hold a charge all day or even more (and when they do have to charge, they would like to fully charge it in a few minutes, not hours). And unfortunately the technology isn't there to meet all of these constraints simultaneously and comfortably. Battery technology even more so, which isn't exclusive to mobile phones or even portable electronic devices in general: just have a look at EVs.

    Then there's the fact that battery runtime is a (strong) selling point, whereas very few people factor battery lifespan into the purchase. Combine this with the relationship between "overcharging" batteries and their reduced lifespan -- and really, there is no law of nature saying you have to stop charging at 4.2 V or 4.3 V or 4.35 V, all you have are different charge limit/lifespan tradeoffs. This translates into perverse incentives for device designers, who push batteries to the limit even if it means they will last a year or two (and some users don't even care since they upgrade their devices every year).

    Oh, and with the drive to ever thinner devices, and users wanting waterproof phones (again a selling point), now you have to make batteries non-user-serviceable. Prior to this you would just buy a new battery for cheap and replace it. Or even keep a battery in a bag, and if you ran out of juice, you'd just replace it. Now this is impossible, and swapping batteries is much more expensive due to the labor required to take apart the phone and put it together again, much more so than the cost of batteries themselves.

    So really, what was Apple supposed to do? Say they cap their batteries at the "ideal" 3.9 V (~60% of the capacity of a battery charged to 4.2 V), turning off the device once it reached the equivalent of ~30% state of charge, and remove any fast charging capabilities; this would lengthen battery lifespan considerably. But then their Chinese competitors would advertise phones with similar thickness and weight, which would last 3 times longer on a charge, and with fast-charging. Sure their batteries would last a year, two at most, but more power to them: the user would just buy a new one, providing extra revenue for the manufacturer. So Apple does what's reasonable, and just goes along with what everyone else does, which is what you would call bad design. Thankfully they've finally been waking up to this issue and adding features such as charge management, optimized battery charging and now this toggle. Of course none of this would have been an issue if they just let the owner of the phone use it as they see fit rather than according to the rules that Apple dictates; i.e. App Store rules won't let you have an app similar to Al Dente in the iPhone.
    You are absolutely correct. Science, engineering, marketing, and customer support (and other concerns) are all interconnected in product development. That’s why product development is so hard.

    Apple cannot control what its competitors do, There is also no neutral third party or sanctioning body to provide guidance or standards for product specifications like there was when automobile manufacturers switched from providing brake horsepower ratings to net horsepower ratings, which were in-fact more indicative of what customers would actually see in their as-built vehicle. It would be difficult to get one smartphone maker to agree to specifying and tracking net, usable battery charge unless all makers agreed to do so. 

    My main concern here is that by bringing battery lifetime concerns into the conversation, which Apple has now done, they are going to be forced to educate their customers about what it means and why these customers aren't seeing the run times on their devices before they hit lower battery charge levels. I used to be able to grab my MacBook or iPhone from its charger in the morning with the assurance that I was starting the day with 100% charge. The first time I see 80% I'm wondering why the device didn't charge up fully, which may introduce a bit of uncertainty about whether I am going to make it through the day. In fact, when I first saw the yellow status light on my MacBook Air instead of the green status light I was wondering what was wrong with the charger or the MacBook. When I saw the charge was exactly at 80% I understood what was happening.
    edited September 2023 watto_cobra
  • Reply 16 of 23
    Wesley HilliardWesley Hilliard Posts: 205member, administrator, moderator, editor
    All of these comments make great points, but I still stand by the fact that it all adds up to: trust the device power management system and just charge your device when you're by a charger. Don't over think it.

    If any of you believe my comments are an attempt to shut down discourse or whatever, it's not. Please, share all the information you have about battery chemistry and such. I'm not arguing that any of that is wrong, it's just misplaced. It's like citing the side effects of a vaccine as a reason not to take it, even though it will save your life.

    And as to my training, yes, I was an electrician but you learn about general applications of many technologies and battery chemistry was a significant factor for some of my work in the navy. When you guys discuss "best practices" and mention the 20-80 rule, I'm just here to tell you that you're not really accomplishing much for all your work.

    If this toggle makes you feel warm and fuzzy, turn it on. But I will say it's next to pointless for most people.

    Your device does plenty to prolong its battery life. My indignation towards the battery topic stems from annoyances from the folks that believe Apple is intentionally breaking their products to sell more -- which is lunacy.

    This whole discussion sounds to me like buying a car and driving only once a month to make sure the tires don't wear too much. It's a product that's meant to be used, so use it. All this discussion is about how to not use it, which is wild to me.
    dewmeFileMakerFellerwatto_cobra
  • Reply 17 of 23
    A few years ago I wrote to Apple to ask for something similar for laptops. I mostly buy laptops, but 99% of the time I use them at home plugged in, and on occasion I use them elsewhere, but almost never far from an outlet. So I basically always use them plugged in, and like to just leave them plugged in rather than unplugging them every time I turn them off, ... Maybe someday…
    This, at least, you can have. As I sit here with my MBP, it's plugged in and its battery is charged to 80% and the battery menu says "Charging on hold (rarely used on battery)" because I have been travelling only with my iPad lately. Perhaps someone did listen.

    On Ventura (at least) look for it in System Settings > Battery > Battery Health and the 'I' in a circle.
    williamlondonFileMakerFellerwatto_cobra
  • Reply 18 of 23
    OferOfer Posts: 246unconfirmed, member
    A few years ago I wrote to Apple to ask for something similar for laptops. I mostly buy laptops, but 99% of the time I use them at home plugged in, and on occasion I use them elsewhere, but almost never far from an outlet. So I basically always use them plugged in, and like to just leave them plugged in rather than unplugging them every time I turn them off, but as a result my batteries periodically swell up and need to be replaced. I think it’s happened 4 times over the years. One Apple Store employee told me their laptops “weren’t designed to be left plugged in,” although they obviously were left plugged in at the Apple Store. With a previous model, I eventually just took out the battery and used it without one, although it’s nice to have battery backup for emergencies, and these days removing the battery is not as easy. What I asked for was a “desk mode” that would just maintain the battery at a modest level without charging frequently, and if I knew I was going to need more of a charge I could just switch out of desk mode ahead of time. Maybe someday…
    Umm, Apple laptops have supported a smart charging mode on laptops that are left plugged in for years.
    williamlondonFileMakerFellerwatto_cobrajony0
  • Reply 19 of 23
    No doubt that those who are always by a desk or in a car will want to use this feature. I certainly would too. Particularly thinking about the increase in docks and the use of the phone as an office camera, many more phones will be holding a +80% charge that is unnecessary harmful. It’s a feature I understand will make a significant difference to the battery life of those who toggle it on. I think the author of the article has missed the mark on the unequivocal recommendation that it makes no difference.
    watto_cobra
  • Reply 20 of 23
    chasmchasm Posts: 3,329member
    mr. h said:
    Who’s the expert here? You? Because your article is dead wrong.
    Mr. Hilliard’s article explicitly says exactly what you are saying: that charging over 80 percent contributes to the degradation of the battery (somewhat) over years of use. I’m not sure how you missed that, but everything you claim is also already in the article.

    But in the REAL WORLD that you don’t apparently inhabit, most iPhone users will change their iPhone for a newer one in about two to three years time — LONG before the difference between Apple’s Optimized charging (the default) and the hard limit of 80 percent (the ideal) will make a material difference.

    I have an iPhone XR I still use irregularly and I’ve been avoiding overcharging it that whole time — and the battery is still above 80 percent health as a result, even after five years.

    Wesley’s article is EXACTLY right: Apple has introduced this limit for people who plan to keep their phone for a long time, but in the REAL WORLD Apple’s optimized charging will help keep their battery healthy **for the length of time they are likely to have it**.

    It’s a pity you weren’t able to comprehend the article, but maybe re-reading it would “optimize” your misunderstanding.
    williamlondonmuthuk_vanalingamwatto_cobrajony0
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