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BigMcGuire

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Jan 10, 2012
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Does the iPhone 14 Pro / Pro Max have the ability to run completely off of external power supplies and not rely on internal battery?

It is my understanding that unlike MacBooks, iPhones / iPads will run on battery power even when plugged in. Your MacBook can run entirely off of wall power - bypassing the battery - and use no cycles if you leave it plugged in for a long period of time. The iPhone cannot run off of wall power only, take out the battery, it cannot power on even if plugged in.

Reason why I ask is --- I got a 14 Pro recently (sold 13 PM to a relative) and I usually leave a new phone plugged in for a few days while it does all its stuff and settles down.

1678138054971.jpeg


Battery usage is tiny for setting up a new phone and downloading over 100GB. For the first two days the phone was fairly warm - even got the "Holding charging until phone cools down" message on Saturday - some on Sunday - was plugged in for most of those days. Battery usage should be a lot higher based on my past iPhones. Today it's been plugged in all day and note the 0 battery usage despite 2+ hours of screen on time.


I am using an Apple MagSafe Battery ... but that shouldn't matter because it'll charge the phone the same way a MagSafe charger would, right? A bug? Other people experiencing same? My 13 Pro Max definitely didn't do this despite being plugged in all day.

Thanks for feedback.
 

Apple_Tiger

macrumors member
Jan 23, 2023
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One thing i notice is that even if just kept on wall and plugged in, i notice that the battery still goes on sailing mode and once it reaches 94% it will trickle charge back to 100
 
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BigMcGuire

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Jan 10, 2012
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One thing i notice is that even if just kept on wall and plugged in, i notice that the battery still goes on sailing mode and once it reaches 94% it will trickle charge back to 100
Yeah noticed same thing yesterday. Been plugged in all day and just within the last hour it’s slowly dropping to 95%. So the usage is finally showing a little bit.

I don’t remember my 13 PM doing that.
 

Apple_Tiger

macrumors member
Jan 23, 2023
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59
Yeah noticed same thing yesterday. Been plugged in all day and just within the last hour it’s slowly dropping to 95%. So the usage is finally showing a little bit.

I don’t remember my 13 PM doing that.
Yea i'm not really a battery expert but i noticed that with my 12 pm, when it's plugged in overnight, it doesn't sail. So I don't know what is causing some batteries to sail and others don't?🤔
 
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BigMcGuire

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Jan 10, 2012
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Yea i'm not really a battery expert but i noticed that with my 12 pm, when it's plugged in overnight, it doesn't sail. So I don't know what is causing some batteries to sail and others don't?🤔
Mine is on its way to 90%. Lol. Kinda cool. Has to be a lot better for the battery.

1678146959964.png


If I press and hold on the battery symbol when I pull down from top right :

1678147030609.png


Edit: Maybe that’s a MagSafe battery thing? https://www.knowyourmobile.com/user-guides/iphone-magsafe-battery-pack-charging-problem/

https://www.reddit.com/r/apple/comments/or1lgc
 
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Apple_Tiger

macrumors member
Jan 23, 2023
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Mine is on its way to 90%. Lol. Kinda cool. Has to be a lot better for the battery.

View attachment 2169419

If I press and hold on the battery symbol when I pull down from top right :

View attachment 2169421

Edit: Maybe that’s a MagSafe battery thing? https://www.knowyourmobile.com/user-guides/iphone-magsafe-battery-pack-charging-problem/

https://www.reddit.com/r/apple/comments/or1lgc
Oh yea as for the MagSafe battery it will charge up to 91% and will remain using magsafe battery until that is 0.

Edit: I suppose you can force it to charge past 90% which I wasn't aware of.
 
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BigMcGuire

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I really think it’s bypassing the internal battery - may just be the MagSafe battery.

Note the hours used vs battery usage. 5 hours 15 mins of screen on.

1678162566089.jpeg


Tomorrow I won’t use the MagSafe battery but I’ll leave it plugged in. Then the next day just normal internal battery. Will report results.
 

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BigMcGuire

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So I decided to test just using internal battery today.

Check it out:

1678210185418.jpeg


Only 1 hour of screen on time and already I've used the same battery as when I had almost 6 hours of screen on time with the MagSafe battery.

I really think it's running off of the MagSafe and bypassing internal! First time I've seen that on iOS. Charge cycle reflects my findings too (just 1).

If this is the case, one could significantly reduce charge cycles is by using an Apple MagSafe battery all day (when you're at home and not out and about) lol. (I won't be doing this, but interesting observation nonetheless).
 

compwiz1202

macrumors 604
May 20, 2010
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Oh yea as for the MagSafe battery it will charge up to 91% and will remain using magsafe battery until that is 0.

Edit: I suppose you can force it to charge past 90% which I wasn't aware of.
This is why I liked the Smart Battery Case. It would use the case power before the battery. And you can see the battery level in the widget. Does it show the MagSafe brick battery level the same?
 

BigMcGuire

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Jan 10, 2012
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This is why I liked the Smart Battery Case. It would use the case power before the battery. And you can see the battery level in the widget. Does it show the MagSafe brick battery level the same?
For me it only shows the battery in the battery widget when I pull from left. It also does a nice little graphic when I first put it on the phone.

1678211866133.jpeg


1678212673244.jpeg
 
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reppans

macrumors 6502
Dec 2, 2006
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In a sense, all Li-ion gadgets bypass the batt and run off of AC when they hit peak charge - Battery Management Systems cannot overcharge Li-ions or they risk fire. Lots of devices have options to limit the peak charge to 80-85% (laptops, Samsung phones), or 90% (MagSafe), but that’s quite different than an option to truly bypass (ie, not charge) a battery while plugged in. Eg, plug-in @30% SoC and the battery just sits there at 30% while operating the device off AC. That would be, by far, the easiest on batts - neither stressing high SoC, nor cycle count. I’m not aware of anything that provides this BMS option though, except for manually removing the battery pack from a laptop, for example.

If we assume that all these devices will always charge to these manufacturer-defined peak levels (80-90%), then the question I think you’re asking is - is it better for the battery to stay plugged-in to limit/stop the cycle count? From the credible/corroborating batt research I’ve seen, IMHO probably not.

Seems 80-90% SoC (while certainly better than 100%) is still in the high SoC stress zone - you need to get below ~60% to be stress-free, and in the ideal storage range. If you believe that NASA article (cycling 60-0-60 for 8yrs/40k cycles), then it seems cycling in this lower SoC band is virtually stress-free and effectively permits unlimited cycles. (There’re other good scientific articles that basically say the same thing).

So if a MagSafe batt effectively keeps the main battery in a 90% ‘storage’ state, then the relatively high SoC should decay the battery faster than someone fully cycling a batt like NASA.


52248945888_ed98220dbb_o.jpg
 
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BigMcGuire

Contributor
Original poster
Jan 10, 2012
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the Alpha Quadrant
In a sense, all Li-ion gadgets bypass the batt and run off of AC when they hit peak charge - Battery Management Systems cannot overcharge Li-ions or they risk fire. Lots of devices have options to limit the peak charge to 80-85% (laptops, Samsung phones), or 90% (MagSafe), but that’s quite different than an option to truly bypass (ie, not charge) a battery while plugged in. Eg, plug-in @30% SoC and the battery just sits there at 30% while operating the device off AC. That would be, by far, the easiest on batts - neither stressing high SoC, nor cycle count. I’m not aware of anything that provides this BMS option though, except for manually removing the battery pack from a laptop, for example.

If we assume that all these devices will always charge to these manufacturer-defined peak levels (80-90%), then the question I think you’re asking is - is it better for the battery to stay plugged-in to limit/stop the cycle count? From the credible/corroborating batt research I’ve seen, IMHO probably not.

Seems 80-90% SoC (while certainly better than 100%) is still in the high SoC stress zone - you need to get below ~60% to be stress-free, and in the ideal storage range. If you believe that NASA article (cycling 60-0-60 for 8yrs/40k cycles), then it seems cycling in this lower SoC band is virtually stress-free and effectively permits unlimited cycles. (There’re other good scientific articles that basically say the same thing).

So if a MagSafe batt effectively keeps the main battery in a 90% ‘storage’ state, then the relatively high SoC should decay the battery faster than someone fully cycling a batt like NASA.


52248945888_ed98220dbb_o.jpg
Very good point and observation - thank you for your post!

Agreed, it's probably better to cycle at lower % than staying at 90% and not using charge cycles.

Another thought: One factor I see is that charging at 90-100% is done at a significantly reduced rate than charging below 60%. The MagSafe battery and the iPhone is very cool at 90-100% but under that, especially plugged in, both devices get too uncomfortably hot for me. BUT I agree completely that doing a 40-60 (or even 0-60) is much better for longevity.

That and, I can't stand how heavy the battery is (and wide). I got the 14 Pro for mobility so I won't be using it to reduce cycles.

My biggest surprise was seeing it not report internal battery usage while the MagSafe battery was connected. Kinda cool. I do wish I could set my iPhone to a charge level like I do with my Mac (AlDente).

I just need to get out of my habit of always wanting my device to be fully charged. lol.
 

reppans

macrumors 6502
Dec 2, 2006
252
143
So the CC/CV (constant current / constant voltage) algorithm is the typical li-ion charge routine, and that will always translate to quick/linear charge up to ~80%, than a curve that slows charge current as it approaches 4.2v.

Folks often worry about heat, but as indicated in the above chart, 60c @ 75% SoC (red circle) seems less stressful than 100% SoC @ 25c (yellow circle). Then consider how much time even a fast charge phone spends charging (an hour?) vs the typical Apple ‘optimized’ charge hitting 100% charge @ 5am then often not falling below 90% for many hours after. IMHO if you’re not concerned with a 100% charge, then certainly don’t need to worry about charge heat either.

I know we’ve discussed this before - a smartplug automation can handle all the hassle/tending of a custom charge optimization - but yes, you are spot on that it is a big mentality adjustment to feel comfortable walking out the door with only 30-50% SoC.

FWIW, as an outdoor enthusiast, I always pocket EDC a Li-ion flashlight with micro spare batt/charger, that can also charge my phone. So I always have back-up charge capabilities, but I have yet to need it for my phone. That’s how i get comfortable walking out the door with a relatively low SoC.
 
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