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

[840quadra]

It would be worth reading the conversation you are responding to before replying that someone's response isn't relevant or ignores details. Providing new details in the present doesn't mean I ignored them in the past. It is also sometimes good to not assume the person you're talking to knows less on a subject than you do.

You replied to me, not the other way around.

Thanks for your viewpoint on the subject.

 

[Analog Kid]

You replied to me, not the other way around.

To correct the record, this is what I mean about reading the conversation you're replying to-- you'd see that you were, in fact, replying to me to question the relevance of my comments or incorrectly say I selectively ignored details.

exactly what does that have to do with preserving battery health?

Your focus on my mention of zinc batteries, ignoring all else is telling.

If you've nothing else on battery health, we can leave it here.

 

[840quadra]

To correct the record, this is what I mean about reading the conversation you're replying to-- you'd see that you were, in fact, replying to me to question the relevance of my comments or incorrectly say I selectively ignored details.

If you've nothing else on battery health, we can leave it here.

6 Months of testing in a pseudo lab environment by an influencer is a great data point, but it is just a small data point in the vast history of Lithium ion devices. I applaud (and on my account) liked the video and appreciate the rare straight to the point delivery which is rare on YouTube accounts as followed as his.

Test variables are a great starting point but far from comprehensive enough for me to switch my use and charging styles.

• What temperature was the room these phones these were tested in?
  • Many documents indicate the heat generated by fast charging is the killer more than how quickly those cells store the energy. Testing these devices in the low 60s ambient temp is going to impact less than in a room if it was in the 80s or 90s.
• are the phones he tested 100% new and manufactured with the same battery revision with 0 Cycles at the start point of these tests?
• What CPU / GPU load does the "discharge" app place on the device?, in turn, what temperature do the devices reach during the discharge tests?
• After discharge, do they let the devices cool, or do they dive right into charging (it appears so from the video).
• During charging, what temperatures do the phones reach?

The Test results are of limited value without knowing more, or testing in in more varied situations that real users will place their devices in for a full (true) 6 months or further in various types of climate and varied uses for even a single individual.

• overall the sample size is quite low on both iOS and Android.
• Were the phones ever taken down to Zero and charged and held to confirm calibration of the indicated battery life / health? They never mention this, and it is something that iFixit and in the past Apple strongly recommended to reset battery life / health indicators.
• Video doesn't really go into if discharge app is running while charging. It sounds like the discharge cycle starts after charging is complete, but the detail is muddy.
  • A mixture of both would be a good data point as many use their phones while they are charging.
• Standing the phones up like they are is an ideal situation for cooling, not representative of how many people do charge their phones
  • charging in a hot car
  • charging in their car in the winter
  • charging on a surface that doesn't dissipate heat
  • charging under a pillow (yes people do this)
  • charging leaving their phone in the sun
  • charging while using the phone (screen on)
• The test checking the stress of storing a device at 3 preset charge levels for just a week is far, far, too short for any reasonable data to be gathered.

I appreciate the video, and the data, but I stand behind following the suggestions to properly maintain this technology, and what the industry and larger entities have shown in their tests.

Regarding my introduction of UPS systems to the conversation

I feel strongly that UPS battery systems are relevant to the conversation as they are effectively scaled up versions of what we all walk around with in our pockets. That is due to their integral, per-cell BMS systems. Thermal impacts on life are similar.

Going back a post, Cell types are commonly split into 3 groups cylinders, pouches, and prismatic cells. Our phones and laptops typically have Pouch style, however in most cases (taking chemistry) they act the same scaled up or down with regards to impacts to thermals on charging, and overall longevity.

UPS system batteries are far more complex than just a simple array of series or parallel connections. They are more akin to RC car balance chargers, but have much more complex sampling and overall data points. These large Lithium deployments have a comprehensive BMS (Battery management System) that will monitor and control the charging / float / discharge on every single individual cell within these much larger systems. Each cabinet has a dedicated computer system that works to ensure good battery health, and work to prevent thermal runaway events.

What kills these UPS system batteries are the same types of variables that hurt the overall longevity of our phones. Could be manufacturer propaganda, but many of the UPS systems training professionals reference our common cell phones when discussing how they learned from small electronics how to properly manage their larger cells.

Could be placebo, but in my collection of iPods, iPhones, older iBooks, MacBooks / etc, I feel that applying what I have learned has helped keep these systems quite reliable. Still regularly use an iPad 3 with its original battery, iPhone 4 with only its 2nd battery, and just last month finally replaced the original battery in my 5th gen iPod.

 

[zkap]

What a channel that is, the production quality, skill and effort put into it are like nothing I've seen before. A test spanning a couple of years is condensed into a 7-minute video, whereas any other Youtuber would have made a 20-minute video about a "test" spanning a couple of hours or days. Even the shorts have incredible production quality, making any other Youtube account look amateurish.

 

[Analog Kid]

6 Months of testing in a pseudo lab environment by an influencer is a great data point, but it is just a small data point in the vast history of Lithium ion devices. I applaud (and on my account) liked the video and appreciate the rare straight to the point delivery which is rare on YouTube accounts as followed as his.

Test variables are a great starting point but far from comprehensive enough for me to switch my use and charging styles.

• What temperature was the room these phones these were tested in?
  • Many documents indicate the heat generated by fast charging is the killer more than how quickly those cells store the energy. Testing these devices in the low 60s ambient temp is going to impact less than in a room if it was in the 80s or 90s.
• are the phones he tested 100% new and manufactured with the same battery revision with 0 Cycles at the start point of these tests?
• What CPU / GPU load does the "discharge" app place on the device?, in turn, what temperature do the devices reach during the discharge tests?
• After discharge, do they let the devices cool, or do they dive right into charging (it appears so from the video).
• During charging, what temperatures do the phones reach?

The Test results are of limited value without knowing more, or testing in in more varied situations that real users will place their devices in for a full (true) 6 months or further in various types of climate and varied uses for even a single individual.

• overall the sample size is quite low on both iOS and Android.
• Were the phones ever taken down to Zero and charged and held to confirm calibration of the indicated battery life / health? They never mention this, and it is something that iFixit and in the past Apple strongly recommended to reset battery life / health indicators.
• Video doesn't really go into if discharge app is running while charging. It sounds like the discharge cycle starts after charging is complete, but the detail is muddy.
  • A mixture of both would be a good data point as many use their phones while they are charging.
• Standing the phones up like they are is an ideal situation for cooling, not representative of how many people do charge their phones
  • charging in a hot car
  • charging in their car in the winter
  • charging on a surface that doesn't dissipate heat
  • charging under a pillow (yes people do this)
  • charging leaving their phone in the sun
  • charging while using the phone (screen on)
• The test checking the stress of storing a device at 3 preset charge levels for just a week is far, far, too short for any reasonable data to be gathered.

I appreciate the video, and the data, but I stand behind following the suggestions to properly maintain this technology, and what the industry and larger entities have shown in their tests.

Regarding my introduction of UPS systems to the conversation

I feel strongly that UPS battery systems are relevant to the conversation as they are effectively scaled up versions of what we all walk around with in our pockets. That is due to their integral, per-cell BMS systems. Thermal impacts on life are similar.

Going back a post, Cell types are commonly split into 3 groups cylinders, pouches, and prismatic cells. Our phones and laptops typically have Pouch style, however in most cases (taking chemistry) they act the same scaled up or down with regards to impacts to thermals on charging, and overall longevity.

UPS system batteries are far more complex than just a simple array of series or parallel connections. They are more akin to RC car balance chargers, but have much more complex sampling and overall data points. These large Lithium deployments have a comprehensive BMS (Battery management System) that will monitor and control the charging / float / discharge on every single individual cell within these much larger systems. Each cabinet has a dedicated computer system that works to ensure good battery health, and work to prevent thermal runaway events.

What kills these UPS system batteries are the same types of variables that hurt the overall longevity of our phones. Could be manufacturer propaganda, but many of the UPS systems training professionals reference our common cell phones when discussing how they learned from small electronics how to properly manage their larger cells.

Could be placebo, but in my collection of iPods, iPhones, older iBooks, MacBooks / etc, I feel that applying what I have learned has helped keep these systems quite reliable. Still regularly use an iPad 3 with its original battery, iPhone 4 with only its 2nd battery, and just last month finally replaced the original battery in my 5th gen iPod.

Thanks for the reasonable and detailed response. While I understand your point that the sample size is small and uncontrolled variable remain, this is one of the more thorough treatments I’ve seen. Many technical papers on LiIon life use very small sample sizes as well.

Temperature is important, but not ambient temp so much as cell temp, which the charge controller should be monitoring and keeping in range regardless of environment and charge rate. As to whether it was in a hot car or under a pillow, I think those are separate questions from this— don’t do those things regardless of how you charge it.

He did not run an application while discharging (other than his monitor app)— he says at the end that he’d like to try that experiment next.

I still don’t think UPS systems are a good reference for phone maintenance, and trainers talking about the phone in your pocket is most likely not propaganda so much as trying to connect to something most people are familiar with. I haven’t seen a BMS charge cells individually, only monitor and attempt to balance cells in a string. And it won't touch the discharge path. The system is still much more sensitive to a bad cell than the phone is.

I do appreciate the fuller response, but until someone can show me evidence of fast charging or full charging a battery truly degrading the life of the phone, it just doesn’t seem worth the effort. This video certainly supports that point— and these were cells rated to 500 cycles. The newer Apple devices are rated to 1000 cycles…

 

[okkibs]

these were cells rated to 500 cycles. The newer Apple devices are rated to 1000 cycles…

Keep in mind that they're the same batteries (i.e. using the same battery technology) and the change in rating is merely that, a change in rating. If they had modified the batteries from one year to the next in order to double the rating that would be major news. Back then this was discussed in the forums here.

I think the rating changed going from the iPhone 14 series to the iPhone 15 series which had very similar battery life (it seems the 14 Pro had a bad batch of factory installed batteries that gave out earlier than usual though).

Apple isn't making batteries of their own design ("Designed in California") instead they just buy batteries from a supplier like other smartphone manufacturers do so if there was a major change in batteries suddenly switching to being rating for twice the charge cycles then every other manufacturer would have also seen this change. But we see no major changes in battery life on Androids and iPhones. (The 17 Pro lasts longer but that isn't due to new battery technology. Part of why it lasts longer is that Apple made more space for the battery so the 17 Pro has a larger battery than the 16 Pro.)

Unfortunately, a lot of people can't just pop into the Apple Store across the street and slap $100 on the counter. Either because they don't have $100, there isn't an Apple Store within a hundred miles, or both.

That is true. Especially if you have a low cost iPhone SE the battery replacement price is steep. But there is a big amount of users who buy iPhones that cost over a grand and then they don't consider that the battery will at some point need replacing? Sometimes they straight up say that they are buying a new iPhone early because the battery life got worse.

It seems to me that many people are allergic to getting a battery replacement and I don't understand it. Especially if you don't have the money to replace the phone early you want to maximize the life of the device. And yes that can include enabling the charge limit, but it should also include thinking about and picking a device that suits your needs where you can get a battery serviced. Especially in countries without any official Apple presence you run into the risk of not being able to even get repairs if the device breaks on its own.

Of course I can see that this might sound privileged when there are places where you just can't get a replacement battery, and smartphones with user replaceable batteries are almost extinct.

 

[840quadra]

Thanks for the reasonable and detailed response. While I understand your point that the sample size is small and uncontrolled variable remain, this is one of the more thorough treatments I’ve seen. Many technical papers on LiIon life use very small sample sizes as well.

Temperature is important, but not ambient temp so much as cell temp, which the charge controller should be monitoring and keeping in range regardless of environment and charge rate. As to whether it was in a hot car or under a pillow, I think those are separate questions from this— don’t do those things regardless of how you charge it.

He did not run an application while discharging (other than his monitor app)— he says at the end that he’d like to try that experiment next.

I still don’t think UPS systems are a good reference for phone maintenance, and trainers talking about the phone in your pocket is most likely not propaganda so much as trying to connect to something most people are familiar with. I haven’t seen a BMS charge cells individually, only monitor and attempt to balance cells in a string. And it won't touch the discharge path. The system is still much more sensitive to a bad cell than the phone is.

I do appreciate the fuller response, but until someone can show me evidence of fast charging or full charging a battery truly degrading the life of the phone, it just doesn’t seem worth the effort. This video certainly supports that point— and these were cells rated to 500 cycles. The newer Apple devices are rated to 1000 cycles…

I agree that the experiment is a great data point and respect what that individual did. Also appreciate your point of view on the subject and understand your reluctance to change. If your device is above 80% (as is my 13 Pro from the same timeframe) why change what you are doing if it is working for you?

Truth be told, I am not a 100% fear mongering individual, and I sometimes have no choice to use a fast charger on occasion, especially on trips where I have little opportunity to wait or don't have a backup (usually my Pixel 8 Pro) phone.

Random thoughts
One tool that I liked with his video is the relay control for charging the phones, some of our customers employ a more elaborate version of the same type of process to control the charge state for racks full of phones and tablets they use for their deployments within datacenters. They don't go into detail what they are using these devices for, but their cycle of replacement (outside of failures) is usually 1.5 years when they swap in fully new devices. I would love to see their data on cell (battery) degradation, and what level they maintain the devices charge. All I know is their system keeps the devices within a "sweet spot" below an even lower 75%.

Even still, I wouldn't consider those racks as a great test bed for long term use of mobile devices, as they employ a wall of fans that pull in 75 degree air from the cold row and exhaust to the front of the rack. Most of us don't put a fan on our devices while we use and charge them. Not even me!

Lastly, Age is a factor of cell degeneration that really isn't and couldn't be tested in such a truncated test situation as in the case of the linked video. I have left devices (for long periods time) which started at 100% and noticed how quickly those batteries degraded when doing so. Since following guidelines to store batteries in a more discharged state, I have had to replace far less batteries for my Drones, Sony & canon cameras, or various apple devices.

I acknowledge that my experiences do not equal any type of scientific tests.

What a channel that is, the production quality, skill and effort put into it are like nothing I've seen before. A test spanning a couple of years is condensed into a 7-minute video, whereas any other Youtuber would have made a 20-minute video about a "test" spanning a couple of hours or days. Even the shorts have incredible production quality, making any other Youtube account look amateurish.

You can access the channel from YouTube by clicking on the account that posted it. Just navigate to the YouTube link and watch the video on that site as opposed to MacRumors.

Also, the test was done over 6 months, not 2 years, many of the commenters on YouTube also miss this small but important detail.

It took 2 years for them to have a successful completed run and this was the 3rd try. My concern is the status of these devices at the point in time they posted the video, as the iPhone 12 was discontinued 22 months ago. They state they were new, however September 2023 was some time ago, and they don't go into detail if they refreshed the devices (meaning new in box) per trial run. I hope (and may have missed him saying so) that each attempt was with brand new devices.

Regardless, like many battery technologies, unboxed or not Lithium degrades over time and we don't know the conditions the devices were stored in over the period of time before the devices were tested. When purchasing iPhones in bulk (for work deployments), they come in box at various levels of charge. Levels of charge when stored have an impact on cell breakdown.

Overall I think it was still a great test. I am looking forward to seeing what this channel does in the future, as they do FAR better job of this work than some of the large "influencer" YT producers that I personally avoid and fully reject any of of their findings.

 

[Poisednoise]

They state that they counted one charge-discharge of the 5-100% group as 0.95 cycles, and one charge-discharge of the 30-80% group as 0.5 cycles. That means that to reach the 500 cycles, they performed 526 charges-discharges for the 5-100% group and 1000 charges-discharges for the 30-80% group. This should also correspond to roughly the same total discharge time.

What would be interesting is if the lower end (5 vs. 30%) or the higher end (80 vs. 100%) matters more. It's certainly not clear that they would contribute equally to the degradation.

Apologies, I clearly missed that in the video! That makes much more sense.

 

[Analog Kid]

One tool that I liked with his video is the relay control for charging the phones,

I thought the sensor that could detect a crash was pretty well thought through too.