iPhone 12 promax battery health at 87% after one year?

betterpath2016 wrote:

I got my charge cycle count checked, and it’s currently at 173. Is that normal?

87% after 173 cycles isn't typical. However, Apple doesn't guarantee anything other than if it drops to under 80% battery health before it reaches 500 cycles. I've heard of batteries being replaced by Apple as a warranty service if it dipped under 80% within the warranty period and before it reached that 500 cycle number.

But again, if you really need to extend your use until you can get a replacement, try a USB battery pack. As long as you use it as much as possible on external power, the battery isn't likely to degrade much since it's not being used much.

Nymedic62 wrote:

Is that why my iPhone 12 battery blew up? Was told by apple support not to leave charging overnight

You were completely told the wrong thing. COMPLETELY. Apple itself recommends charging one's iPhone overnight as standard procedure. An iPhone can be left on its charger for days with zero harm. iPhone has overcharge protection and only takes a charge up to 100% when it needs a charge.

More to the point, this is the specific reason Optimized Battery Charging is part of the charging program for iPhone. The phone SHOULD be charged in to charge at night, with Optimized Battery Charging enabled and the phone will learn from your daily pattern, charge the phone up to 80%, then stop charging until it knows it's time to be used, where it charges the phone up to 100%. The added benefit is the phone will backup when connected to Wifi and the screen locked nightly while you sleep.

Whoever told you otherwise, is simply, utterly, wrong.

There are a ton of variables that determine how long a battery lasts and some of it is just randomness. As for going into thermal protection mode, it's kind of complicated. It's heat that's a primary reason for batteries losing capacity prematurely. There's a ton of stuff done to reduce the heat when charging in order to minimize loss of battery capacity, but that's something that's cumulative. But having it go into thermal protection mode a couple of times may not necessarily cause "damage" that's enough to measure. If you keep on doing it then maybe it will start to really degrade.

Apple's nominal rating is 80% battery health after 500 complete cycles, but this is a simplification. Some batteries do better and some do worse. A complete cycle can be from 100% to 0%, twice from 75% to 25%, or any combination where it drains "100%" of the capacity. It's not perfect, but it simplifies the rating in a way that's easy to understand. I could easily imagine being at 87% after a year if there's close to a full battery cycle used every day.

If you're really just trying to put this off until replacement time, you might try an inexpensive USB power pack that will provide power.

betterpath2016 wrote:

I found a few on Amazon that are charging cases.

do they have ones where I can use the external battery all the time? I’m trying to make the health not go down as much. What about keeping it on the charger for a long time? Apple told me that I should always take it off the charger once it reaches 100% as keeping it on the charger after that damages the battery.

Something like that should be fine. I don't use a charging case per se, but carry a number of different USB power packs with short (4 inches long) USB-A to Lightning cables.

There's nothing particularly damaging about connecting to a power source when it's at "100%", and I say that in quotes because 100% is a chosen limit and not absolutely the maximum that the battery is capable of storing. All competently designed lithium-ion battery charging systems stop charging once it reaches "100%". If it's continuously connected to power, it will slowly drop due to self-discharge and supplemental power from the battery until it reaches a certain level where it will charge up to "100%" and stop. You're not going to be able to see this happening with an iPhone though because of the way it reports the charge level. It will always report 100% when it's continuously connected to power and not draining faster than the power source can supply. Other Apple devices (like Macs) report battery capacity differently.

There are a lot of little things that might theoretically help with battery longevity, but it can be highly impractical to implement them unless the process is automated. About the only thing that Apple has that the user can program is "optimized battery charging" where it will attempt to learn the user's battery usage and then may charge only to 80% in the evening and then finish up the charge to 100% in the morning when the user may be ready to remove it from external power.

caedmon65 wrote:

You can use your phone at any battery health percentage without it being dangerous or having serious trouble. It will only start having a more noticeable affect when it drops below 80%. It will still be usable until the battery breaks. It is normal for it to drop that much, but as long as there isn’t a huge performance decrease than you are probably ok.

At a certain point the battery degradation will also mean it can't supply as much current. Not sure what Apple does now, but remember the throttling issue a few years ago and the $29 (in the United States) promotional replacement service? Rechargeable batteries have lower peak current capability as they lose capacity. That's inevitable.

That being said, I had my iPhone 4s for about 5 years where I'm sure it had at least triple the 200 cycle nominal rating for 80% battery health. It certainly didn't turn into a pumpkin, but by the time I retired it, I was maybe only getting about 30 minutes of run time and the battery reading would sometimes jump maybe 10% in front of my eyes. I never saw a complete shutdown unless it was around 0%. When the battery is that degraded, the battery reading just isn't that reliable.

lobsterghost1 wrote:

You were completely told the wrong thing. COMPLETELY. Apple itself recommends charging one's iPhone overnight as standard procedure. An iPhone can be left on its charger for days with zero harm. iPhone has overcharge protection and only takes a charge up to 100% when it needs a charge.

There's always the possibility of some sort of manufacturing defect or malfunction. However, using a device thinking that it's going to malfunction is rather counterproductive.

caedmon65 wrote:

Apple devices actually have a feature that allows them to be plugged in all night. They learn from your usage of the device and will wait to charge past 80% until a time you would usually use your device. It is not the best to leave them plugged in all night, but I do and I haven’t had problems in the past.

That is an opinion statement, not based on any facts at all. iPhone is designed to be plugged in all night. Thus, it cannot be not good to do so.

betterpath2016 wrote:

It has 182 charge cycles. When Apple does a diagnostic test on my battery, they say it’s not damaged. Are you supposed to let die once a week or so? I haven’t let my phone drop past 20% battery power. My friend got the same phone as I did a week later, and her battery health is at 88%. She says it’s because she lets it die every week.

There are no guarantees about batteries. They're possibly the weakest link in any portable electronics. They can do all sorts of things including fail prematurely, swell, or lose capacity slower or faster than expected. I had a Mac battery that was at about 94% battery health (it's always been available) as soon as I got it, but I couldn't claim it as defective under warranty.

Apple doesn't really make any specific recommendations for how to use a battery other than a recommendation to keep it cool (perhaps not charge in a case) and to turn on Optimized Charging. However, there may be behaviors that can marginally affect battery life. That being said, Apple simplifies their nominal rating into 500 cycles to 80% battery health. It's impossible that this is perfect for every single iPhone since the iPhone 5 under every single condition for getting to those 500 cycles. Your results may vary. I have a battery now that lists 92% battery health at nearly 600 cycles and I don't know if I did anything specific that resulted in this, although i suspect that it's due for an update.

If you really feel that you need it, then you can get a battery replacement service. There really isn't anything that can be done other than to either live with it or have it replaced.

You can use your phone at any battery health percentage without it being dangerous or having serious trouble. It will only start having a more noticeable affect when it drops below 80%. It will still be usable until the battery breaks. It is normal for it to drop that much, but as long as there isn’t a huge performance decrease than you are probably ok.

Nymedic62 wrote:

Absolutely the worse thing you can do. It should be unplugged at 100% charge.

That’s untrue. It stops charging at a certain point and being connected to power means that the device won’t being drawing power from the battery.

Nymedic62 wrote:

Is that why my iPhone 12 battery blew up? Was told by apple support not to leave charging overnight

Can’t account for what happened to your device, but in general leaving it plugged in isn’t a problem. Charging current levels taper as it approaches 100% and then fully stop. Short top of charges can occur. But it won’t be continuously feeding current to a fully charged battery.

There’s nothing particularly wrong with leaving a device connected to power indefinitely.

betterpath2016 wrote:

I also heard that once it reaches 70-50% health, the battery will swell up and not work anymore.

I don’t know what an usb battery pack is. What is that?

I've had one swollen battery in a MacBook. But that wasn't too bad because Apple sold me a replacement cheaper than the retail price. And that was one where it wasn't closed in my computer, but just puffed out because of the design construction. But that battery wasn't severely degraded (it was under the rated number of cycles), although it was weird because (I kid you not) at times it was reporting negative capacity. I believe that the diagnostics data on the battery was corrupted. But if a battery swells in an iPhone, it will usually physically damage the device before the user realizes that it's swelling.

Lithium-ion batteries don't necessarily swell because they're depleted. The typical reason they swell because there's some sort of defect or damage where the membrane between the layers is compromised. The iPhone 4s I mentioned must have been well under 50% battery health and it didn't swell. I've had other Apple lithium-ion batteries with less than 60% battery health and the only effect was a lower run time and maybe an unpredictable shutdown as it got near 0% capacity.

A USB power pack is just a portable device that provides power from an external battery source. There are other names for them such as USB power banks, power stations, etc. Most contain just a lithium-ion battery, although in the past I've used ones that used AA batteries (I used rechargeables). I carry a lithium-ion battery powered one with me often just to extend the time that I can use my devices without having to find an outlet. It will have at least one USB port to supply power and is usually charged through a USB cable of some kind. I've heard of a few that can charge through a Lightning cable, but those are rather rare. I've bought some that cost only about (US) $10. Here's one available from Apple, although they don't make it.

https://www.apple.com/shop/product/HNYD2ZM/A/mophie-powerstation-mini-universal-battery-5000mah

Apple currently has the MagSafe Battery Pack that will provide power wirelessly, but it costs more than an internal battery replacement.

In addition to all y_p_w wrote above, your friend is actually misinformed about fully discharging her iPhone battery. That can be and often is harmful to Lion batteries. If anything it will promote more rapid Battery Health decline.

betterpath2016 wrote:

Thank you very much for replying.

I wondering if when I had the alert message your iPhone needs to cool down before you can use it, damaged my battery at some point back in May 2021.

I have recently started to use my phone a bit more, as I figured having it basically unusable duty returning on airplane mode, disabling Wi-Fi, turning on do not disturb, and other various means was just wasting my phone. I still have those features turned on, but I’m using it on the charger a little bit more. Optimize battery charging is enabled, however I am unable to get it down to 20% around the same time every time to charge it for a routine.

when I would use it every day before November 2021, I noticed it was a go down by 2% a month. Now that I don’t really use it as much, I get three weeks in between the battery capacity dropping a percentage.

You may be overthinking this. There are just way too many variables. I too have gotten the cool down message when I had it in the sun in my car - several times. Yet somehow mine is reporting 92% despite no effort on my part to do anything special. There's really no accounting for the randomness of battery capacity loss. Apple obviously has expectations based on how it all averages out with all the variables that they simply can't control,. This is distilled into 500 cycles to 80% battery health. This obviously sets up expectations, but there are always going to be variations. That's just kind of the way it works out.

lobsterghost1 wrote:

In addition to all y_p_w wrote above, your friend is actually misinformed about fully discharging her iPhone battery. That can be and often is harmful to Lion batteries. If anything it will promote more rapid Battery Health decline.

Apple doesn't seem to have any recommendations for or against it though. That's all within Apple's allowable operating conditions. They've chosen what 0% is, although that information is proprietary.