In-Depth iPhone Battery Experiment Pits Slow Charging Against Fast Charging

[Analog Kid]

So, is that kid in Junior High, or...?

And already understands the world better than most…

 

[Analog Kid]

Thanks for saving me the 7 minutes.

The creator of the video must be celebrating you guys destroying his views Lol

View it— the methodology and production value are worth it.

 

[tennisproha]

Nope. I gave it all the time in the world (a year or so) - it's meant for people who just plug in their laptop into power same time each night, not for me. You can easily mess it up by changing your routine for just a few days. Al Dente is so much easier. Also has some nice geeky info about power draw. Great for my needs - most of my days my Mac is plugged in, so I keep it below 70%, and I top it up with one click when I need to.

Also, on my other devices, it also just refuses to work. I always ended the day with more than 50% battery on my Watch so for a while it charged only to 80%.... until it just mysteriously stopped doing that and now it always charges to 100, even though my usage or battery levels haven't changed. Why? Apple only knows. For me, their 'estimates' are simply not reliable.

It can certainly be improved with more granular controls but it works well for my needs right now.

 

[seinman]

Almost every device has this option, built it. My Steam Deck. My Switch 2. My Apple devices. And yet, people treat it like it's some kind of hoax.

Because the idiots who fell for the hoax won’t shut up so they put the feature in to stop all the bitching.

 

[Shirasaki]

Why does Apple push the 80% charging limit so hard? I literally cannot shut this off on my AW10 or Ultra2. Even with it disabled on both watches, it still only charges to 80 percent most of the time and I have to have it in nightstand mode to charge it to 100% when I want. It occurs to me that maybe Apple might know something more about batteries and battery life than we do. It is IMPOSSIBLE to get anything useful off of the internet because there is so much conflicting information out there.

Apple has access to battery construction and design circuitry that we users don’t have. Maybe their battery on Apple Watch wasn’t as good as they claimed to be and they had to push the charging limit insanely hard to reduce warranty replacements?

 

[Analog Kid]

Nice, but I am going to follow industry / manufacturer suggestions. I still am rocking a 13 pro with over 80% battery as my work phone, and have turned in my last devices on personal side with 99 - 100% battery health since the 14 pro on.

I have a 13Mini that I charged the hell out of and it has 84% battery. I’d consider trading in a device with full capacity to be a missed opportunity.

 

[rchornef]

For sure.

If you limit yourself to 80% then after 4 or 5 years you can avoid a battery that only... has 80% of it's capacity left?

What exactly have you accomplished?

Let's imagine a phone owned for 6 years. One person limits it to 80% and has 80% capacity for 6 years. The other person doesn't limit it at all and ends up with 80% capacity and maybe a smidge under for a year or two?

...I really don't get it. Like genuinely. How is the first scenario not the obviously, clearly, no brainer, no question worse scenario? How is a capacity life of 100, 96, 92, 88, 82, 80 better than a capacity lifetime by year of 80, 80, 80, 80, 80, 80?

If it is better to keep between 30 and 80%, then if you don’t need more than 80%, except for during the usual circumstances, at the end of four years, you’ll have more battery power when you do charge it up to 100%. It’s exactly the situation for me and my Apple Watch and phone. If I could only set it manually, it would be a trivial thing to do, no sweat no worry, no algorithm. It’s not really a big deal, it just would be such an easy thing to do manually in Settings, and since it does seem to be better for most lithium batteries across the board, why not just have devices that enable a user to do this? Instead with an Apple Watch version nine I’m subjected to some weird algorithm, and my iPhone 14 Pro has never optimized diddly squat.

 

[Regbial]

Also, on my other devices, it also just refuses to work. I always ended the day with more than 50% battery on my Watch so for a while it charged only to 80%.... until it just mysteriously stopped doing that and now it always charges to 100, even though my usage or battery levels haven't changed. Why? Apple only knows. For me, their 'estimates' are simply not reliable.

Maybe the watch just needs to recalibrate it's battery capacity, since it's s a much smaller battery than a phones, maybe it's just less accurate in general (iPod touch batteries didn't even show percentage, they were so small.. iirc) .. I find with my apple watch if I charge it from around 50-60 or 70 percent consistently, if there comes a day it runs below 30 or so it will shut off.. (so really the battery was actually empty I assume) ... I think you have to charge it to 100 so it recalibrate. I try to do it like once a month or two months.. I use a smart plug and an automation, so I'll set timers for it to charge and turn off. But sometimes I forget and that's when it mostly recalibrates, I assume.. from like 90-100& charge, on my 2nd gen SE..

Try experimenting with that, maybe it'll work if you do.

 

[pablorph]

I really like how this young man has accomplished this study. Kudos to him. Somebody needs to hire this person (and pay him well.)

 

[Kottu]

Used iPhone 12 PM for 3 years, charged however I wanted, battery life was around 86% (800+battery cycles) when I sold it. My 15PM, after 2 years of use with battery charging limited to 80% is currently at 87% @ 569 battery cycles. So, I know that being so careful about charging methods doesn’t help much.
Charge and use your phone however you want. If you want to use it for 4-6 years and want whole day battery life, you need to change the battery after 3-4 years.

 

[svish]

Have not yet watched the video. However I believe that one cannot think too much about the battery and that it is best to charge whenever one needs to. But I prefer generally not to take the battery below 20% and start charging at around that level and charge all the way to 100%.

Keeping a charge limit of 80% effectively reduces the available battery capacity to 80% or even just 60%(20 to 80) and that is not a very good idea for me. Of course if one is having access to a power point throughout the day then one could consider keeping the 80% limit.

Overall best is not to think or worry so much about the battery. For me it is just fun to see the cycle count and battery health of my devices!!

 

[fromgophonetoiphone]

iPhone 12 only charges at 20W max, so it's not really a good candidate to talk about fast charging honestly. You need to be going much faster and even 30W is questionable if that's fast or not. 45W or faster maybe then we're talking is fast charging.

 

[kaz911]

Analysis: Does wireless charging wear down your iPhone battery?

We asked readers about their charging habits and the data revealed a surprise.

www.macworld.com

Wireless charging has next to zero impact in battery life.

I don’t think that is quite right.

My phone gets very hot during “wireless” charging. Batteries in enclosed spaces do not like heat. And the heat is a byproduct of “wasted energy” - so not only does it make your phone hot - it uses more energy per Wh charged into the phone’s battery.

So if you want to be kind to your phone AND the environment you should never use wireless chargers.

 

[platinumaqua]

Anything to prolong the battery health is good in my opinion, even if it didn't have a significant impact.

 

[Nekomichi]

If you charge your device to 100%, in two years you'll lose 5-20% of the capacity due to cell ageing.

If you limit yourself to only using the device between 20%-80%, you instantly lose 40% capacity from day one.

 

[SebCohen]

The 80% crowd isn’t going to like that lol.

The BAGA crowd (Battery Gains) 🖖😎

 

[MilaM]

If you typically don't need more than 80%, then it could significantly lengthen the time until you drop below 80% and then replace the battery. The experiment shows that the 30-80% iPhone dropped only 8% in the same time the 5-100% iPhone dropped 12%. Extrapolating, this might mean that if the latter drops below 80% after 3-4 years, the former might take 4-6 years with the same usage to drop below 80%. It might make the difference between having and not having to replace the battery before getting a new phone. In addition, on the occasional days where you know you'll need more than 80%, you'll have opportunity to make use of >80% for longer as well. Of course, if you get a new iPhone every other year, it makes less of a difference.

It's not only about the need to replace. When you take care of your battery, it will have a higher total capacity (100-0%) after three years. Which means that you will get more capacity (time) out of the phone in case you really need it.

 

[Tenkaykev]

The 80% crowd isn’t going to like that lol.

Splutter, splutter, " Well yes, but you can prove anything with data " 🤣

 

[tsupersonic]

The 80% crowd isn’t going to like that lol.

I'm doing 80% charging, only because the 16 PM was an upgrade from the 13's battery. The 16 PM lasts about 24-36 hours on 80% charge for my usecase. If that drops significantly, I have no problem going to 100%. I also charge to 100% during any travel. I'll probably replace the 16 PM before I replace the battery anyway, so in the end it doesn't even matter

 

[adrianlondon]

My iPhone 11 (now 6 years old) was charged to 100% every night on my original 5W charger.

Optimised charging never worked, as I don't sleep/wake to a regular enough pattern for it to work out what to do.

I've now got an iPhone 17, but my 11 has 76% battery capacity left and still lasted the whole day. Not bad for a 6 year old phone.

I've currently set my iPhone 17 to charge to 85%, and my usage (when I'm at home a lot) means it even lasts 2 days with that much charge. I charge wirelessly almost every night now. I'll let you know the outcome of my experiment in 2031 😁

 

[MaxBurn]

I appreciate this work, it's the data I need to see. Been using a 15PM sense launch 80% limit and slow wireless charger, 92% battery capacity after 281 cycles today. Turning off the 80% limit on that, nonsense. Do have a laptop that sits in dock most of the time, leaving that on.

 

[robvalentine]

More than minimally, I would say. The 5-100% iPhone lost 12% capacity, while the 30-80% iPhone lost only 8% capacity. This means the 5-100% iPhone lost battery capacity 50% faster,

But it's such a small amount, it's really not worth crippling your battery at 80% to prolong its capacity drop to 80%.

 

[BeatCrazy]

For sure.

If you limit yourself to 80% then after 4 or 5 years you can avoid a battery that only... has 80% of it's capacity left?

What exactly have you accomplished?

Let's imagine a phone owned for 6 years. One person limits it to 80% and has 80% capacity for 6 years. The other person doesn't limit it at all and ends up with 80% capacity and maybe a smidge under for a year or two?

...I really don't get it. Like genuinely. How is the first scenario not the obviously, clearly, no brainer, no question worse scenario? How is a capacity life of 100, 96, 92, 88, 82, 80 better than a capacity lifetime by year of 80, 80, 80, 80, 80, 80?

Generally solid reasoning but doesn’t acknowledge that (on older iPhones at least) that gradual degradation from 100-80% capacity makes the battery unstable and subject to failure or other misbehaviors in those later years.

I’ve had iPhones like 8, XR and similar that showed 80-82% health but often completely die at 30-40% SoC.

 

[Powerbooky]

wow, just like every other battery test. replace your battery if/when it falls under 80%. otherwise, use your phone as you see fit, folks.

You can easily let it drop below 50% unless recharging during the day isn't an option in the daily routine.
I've used my last MacBook Pro 11 years without replacing the battery - of course it was worn a lot, from 7-8 hours runtime to 1-2 hours tops. Most of the time it was connected to the adapter anyway.
My 1st gen iPhone SE also went below 80% after 3 years or so. By the time it started to randomly shutdown during the simplest tasks, I went to the Apple Store for a new battery.
My current iPhone 13 mini is +3 years old now and capacity according to the OS is 86%. I still can use it all day (05.30-21.30). By the time I place it on the charging pad it's 10 to 20%. It can be stretched when I activate an automation that enables low power mode at 40%.
One exception though... when I hand my phone to one of my kids. Then the battery can be drained 30% in half an hour.


The thing with batteries... I've done my share of research as a student decades ago. Real world results always differ from testing (lab) setups. It's a complex combination of usage, how much power the apps use, how many apps are actually on the phone (background tasks that can't be disabled), how much power is used by the hardware (screen, RF), if you're moving a lot, the actual climate were the phone is and of course the manufacturing quality.
You'll never know how long the battery will last, as all these above factors can change over time.

 

[bigglow]

The 80% crowd isn’t going to like that lol.

I thumb finger at them by going 10-90% and 5W USB-A slow charge until recently.

Startign this week I am doing 2.5W USB-A slow charge until my iPhone 18 Pro Max appears.

Will sell my iPhone 16 Pro Max with 100% battery health!