Charging with Apple MagSafe is harmful to the iPhone battery

Charging with MagSafe lets the iPhone battery age faster

I admit that this claim sounds like clickbait, but I didn't mean to downplay the problem with a “maybe” or “maybe” in the headline because I think it's actually serious.

But let's start at the beginning ...

Problem 1: MagSafe heats up the iPhone significantly

When I received my iPhone 12 Pro with MagSafe, I directly measured the performance (read here "MagSafe charging power measured“) That is used when loading.

The result: The high performance that MagSafe offers when charging, according to Apple, only flows for the first few minutes. Then the charging electronics throttle the power so that most of the time only about 5 watts flow into the iPhone 12 Pro. So most of the time you charge as slowly as with the old 5-watt plug-in power supply units that you used to get with your iPhone. Nevertheless, the iPhone heats up significantly more than is the case with wired charging.

In my opinion, the reason for the slow - apparently artificially slowed down charging via MagSafe - is that the heat generated by the wireless, lossy charging is very strong, but the battery must not exceed a certain temperature when charging.

Charging the iPhone via Apple's MagSafe is comfortable, but neither efficient nor healthy for the iPhone battery (photos: Sir Apfelot).

Charging the iPhone via Apple's MagSafe is comfortable, but neither efficient nor healthy for the iPhone battery (photos: Sir Apfelot).

The fact that I am not alone with the high levels of warming during wireless charging also shows this entry in the Apple support forum.

I once translated the thread in part (with DeepL):

When I charge my iPhone 12 Pro overnight using MagSafe, both the charger and the phone feel hot or warm in the morning, as if I've played a graphics-intensive game for a while. I am concerned that this means that my phone has been in a heated / warm state for the 8 hours that it was charged overnight. That doesn't seem to be good for battery life.

The forum thread is even longer, but in principle these lines are enough. With him, too, the iPhone gets quite warm thanks to MagSafe. For me it was about 37 ° C that I got with the app Coconut battery could measure.

What temperatures are harmful to the iPhone battery?

Admittedly: 37 ° C doesn't sound like much, but if you hold your iPhone in your hand, it feels quite warm - sometimes even hot. But in order to contribute a bit of facts, I did some research to determine the “warmth” at which a smartphone battery can actually be damaged.

The website Wissenschaft-im-Dialog.de has this an interesting article, which draws a comfort limit for the battery at 35 ° C:

Over the years, the electrode materials begin to react with the electrolyte, but also with other materials, and they are increasingly unable to store the lithium ions. If we expose the smartphone to high temperatures of 35 degrees Celsius for too long, the electrodes react faster, which accelerates the aging process of the battery. The battery now has to work a lot harder to provide the same performance.

With the 37 ° C, which I measured with Coconut Battery, we are slightly above this limit.

Charging your iPhone every night with MagSafe is so damaging to the battery in the long run that the maximum capacity drops sharply within a few months.

Charging your iPhone every night with MagSafe is so damaging to the battery in the long run that the maximum capacity drops sharply within a few months.

Constant charging with MagSafe is bad for the health of the battery

Now we have actually already proven it: The iPhone heats up to more than 35 ° C when charging via MagSafe and this - scientifically proven - reduces the battery capacity over the long term. This may not take on tragic proportions if you only charge the iPhone here and there with MagSafe, but if you put your iPhone on the MagSafe charging puck overnight and thus "keep it warm" for hours, the battery is not doing the battery any good.

How good is my battery? The "maximum capacity" shows you!

In the case of the iPhone, the battery health value is below Settings> Battery> Battery status> Maximum capacity displayed.

The following article is interesting (and the actual reason for my blog post) in this context Medium.com. An iPhone user describes how much the maximum capacity of his iPhone 12 Pro has decreased due to constant charging with MagSafe. Here are his two most important statements:

  • iPhone 12 Pro; not even a year old; charged daily overnight via MagSafe; maximum capacity: only 86%
  • iPhone 11 Pro; well over a year old; charged daily via Lightning charging cable; maximum capacity: still 98%

His iPhone 12 Pro has lost a lot more capacity than his iPhone 11 Pro - even though he has been using the iPhone 11 Pro for a significantly longer period of time. From his point of view, the reason for this is to be found in the nightly charging via MagSafe and the resulting warming of the iPhone.

When charging via MagSafe, the battery sometimes only receives around 5 watts, but it still heats up more than when charging faster via USB-C PowerDelivery.

When charging via MagSafe, the battery sometimes only receives around 5 watts, but it still heats up more than when charging faster via USB-C Power Delivery.

And shows that the user is not an isolated case above this thread in the apple forum. A quote from there:

I bought my iPhone 12 Mini 4 months ago. Battery condition> maximum capacity is already at 90%. Normal use, battery lasts for one day, charge at night with MagSafe. Have others had similar experiences?

By the way: The “magic limit” above which the iPhone reports that the battery should be replaced is 80%. The user's iPhone 12 Pro is not far away from this and that after less than a year of use.

Conclusion: charging by cable is the best alternative?

The two values ​​and the statement in the article about the relationship between battery health and temperature only allow one conclusion for me: Charging with MagSafe is not "healthy" for the battery, or the battery ages faster than when you use the iPhone Charging the cable.

Charging with a USB-C cable is only second best

However, you also have to keep in mind that fast charging via USB-C cable also generates more heat than charging with an "old" USB-A-to-Lightning cable. In my tests with USB-C charging cables, I did not get over 37 °C but also 36,5 °C when charging. Accordingly, charging via USB-C is not the best alternative - but at least the best compromise between "fast" and "battery-friendly".

The USB-A-to-Lightning charging cables do not technically allow high charging power - no matter which power supply you use. This is perfect for the iPhone battery (Photo: Sir Apfelot).

The USB-A-to-Lightning charging cables do not technically allow high charging power - no matter which power supply you use. This is perfect for the iPhone battery (Photo: Sir Apfelot).

Battery wellness: charging via USB-A to Lightning cable

The first choice for "healthy" charging is a charging cable that has a USB-A connector on one side and a Lightning connector on the other. The iPhone needs almost twice as long with this cable as with the USB-C fast charging cable, but this makes no difference when charging overnight and it saves the battery.

When charging my iPhone 12 Pro Max via a USB-A to Lightning charging cable, the temperature never exceeded 33 ° C. Significantly less than is the case with MagSafe charging.

When charging my iPhone 12 Pro Max via a USB-A to Lightning charging cable, the temperature never exceeded 33 ° C. Significantly less than is the case with MagSafe charging.

Purchase recommendation for the "wellness shop"

Since I know that some readers cannot do anything with "USB-A-to-Lightning cable", I would like to give you a direct purchase recommendation here:

Buy recommendation for "fast charging"

If you like to charge your iPhone quickly, but still want to go to work halfway battery-saving, you will find the right combination here:

Forecast for the future of the MagSafe store

I think Apple is well aware of the problem. Accordingly, they should continue to make efforts to make wireless charging even more efficient. Ultimately, it is the loss of energy that heats up the battery in the form of waste heat. If you can manage to reduce this loss, you should also reduce the negative impact on battery life.

If you want the maximum charging power, you should make sure that the iPhone stays cool. A shell is rather counterproductive here (photos: Sir Apfelot).

If you want the maximum charging power, you should make sure that the iPhone stays cool. A shell is rather counterproductive here (photos: Sir Apfelot).

Improvements possible through firmware updates

At the moment, the few degrees Celsius that the iPhone heats up to over 35 degrees during MagSafe charging seem to be the problem. If Apple were to change the software of the charging electronics in such a way that, for example, it already reduces the charging current at 34 ° C, then the loss of maximum capacity would possibly be significantly lower.

Of course, this would also increase the loading time of the iPhone via MagSafe, but the bottom line is that this should be ok for most users. Nobody uses wireless charging (even with MagSafe) because it would be particularly fast. In fact, using MagSafe, the iPhone takes roughly twice as long to charge its battery than charging it with a USB-C fast-charging cable.

The good news: Apple could deliver the changes to the loading software without any problems with a firmware update and thus provide an improvement relatively easily.

The “optimized charging”, which Apple delivered a few months ago, should also be a step in the right direction. But despite everything, my iPhone 12 Pro Max still heats up to almost 37 ° C when the MagSafe is charging - I think there is still a need for improvement. Whether this happens naturally is another question. Let us surprise.

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35 comments

  1. Thomas says:

    Have a look. My 12 Pro Max is still at 89% capacity. Bought October 2020. Charge it at night on the MagSafe and have it in a charging cradle in the car during the day that also charges inductively. I'll keep watching that.

    • Jen Kleinholz says:

      Hi Thomas! My iPhone 12 Pro Max was hardly charged inductively, but it was still charged every night and is at 95%. It was a coincidence that I didn't charge with MagSafe because I only have one cable (USB-A) on the bedside table. Every now and then I also loaded it via USB-C PD. And only very rarely inductively.

      But you have to look: Sometimes the "Maximum Capacity" increases when you charge the iPhone. For me, the value was 91% before charging and then went up to 95% while charging. I suppose that will happen when it calibrates.

  2. Raul Gonzalez says:

    Hello, I charge my iPhone 12 Pro overnight via Magsafe, but I switched a WLAN socket in front of the 20W charger so that it switches off after the set time. Works wonderfully, still has full battery capacity after a year.

    • Jen Kleinholz says:

      Hello Raul! You can save yourself that with the socket. In the meantime, Apple has optimized charging so that it only charges up to 80% and then only charges in the last 20% shortly before your usual time to get up. But what do you mean by "full battery capacity"? Really 100%?

  3. Simon says:

    Thanks for the article.
    Then let's hope that Apple will not "optimize away" the connection in the future.

  4. Jochen says:

    Thank you for the detailed information. At the same time, the knowledge that you convey to us also makes me angry. You buy an iPhone for over 1.000 euros, then pay another 45 euros for MagSafe, specially designed from Apple for iPhone 12 and higher, to ruin your battery in a short time. A problem caused by the manufacturer and that has to be accepted? This can not be it. Every year the quality of Apple devices continues to decline and prices continue to rise. The spirit of Steve Jobs has probably left the company for good. Pity!

    • Jen Kleinholz says:

      I understand what you mean. At the same time, however, Apple has to acknowledge that they are at least thinking about how to "save" the battery. They limit the temperature to 37/38 ° C and they charge "optimally" by only filling the battery up to 80% at night and charging the last 20% before getting up. I just think that inductive charging is not yet so advanced in principle that it should be used all the time. The loss is high and a large part of it is then waste heat. I would be interested in how hot the smartphones of the competition get, which charge with 15 or even 20 watts or more. It could be that we at Apple are still quite well served with the temperature and the "minimal damage" to the battery. : D

      • Jochen says:

        Jens, everything you say is correct and for this reason I am a staunch Apple user. Still, I think it would be fair if Apple pointed this out, e.g. B. "Constant use of MagSafe is damaging your battery." I buy original Apple accessories because I want to avoid damage like this. How do you think Apple reacts if your battery only has 2% capacity after 75 years, just because you used the MagSafe advertised by Apple? They won't swap the battery for us for free. From now on I will no longer use the MagSafe and will save my battery. But I don't owe it to Apple, but to Sir Apfelot. THANKS!

        • Jen Kleinholz says:

          Hello Jochen! I don't want to give the wrong impression. Basically every battery ages. Even if you always store and charge it with very little power at 18 ° C ... Not that people think MagSafe is bad and the rest is great for the battery. Nothing is great for the battery, but some things are a bit worse than others ... I would think it would be nice if Apple had built in a limit of 35 ° C for the battery temperature, which you can activate or deactivate yourself. So you could charge quickly when you need it, but charge "healthy" if it doesn't matter how fast it is. But Apple was never good at "options" for the user. Not even with Steve ...

        • Phil says:

          Finally, using a charging cable will also damage the charging port. How many would break within 75 years?

          You get the convenience of wireless charging with Qi, MagSafe for easier phone placement to maintain full charging capacity and reduce the risk of damaging the phone if you trip over the cable while charging and don't close the charging port to damage.

          You run the risk of the battery draining slightly but continuously and charging more slowly.

          So it's a matter of advantages and disadvantages. Everyone is free to choose as they see fit. But while the MagSafe charger has its downsides, so does using a cable.

          There's nothing Apple needs to warn users about, and Apple certainly doesn't have a faulty product. The charger will not "damage" your battery.

          You're not saving your battery because the difference is actually pretty negligible. Phone usage and battery age have a much larger impact on battery health, tenfold.

  5. Jochen says:

    Jens, you didn’t give the wrong impression. I think it's important that you pointed this out in your article. Thanks again for that.

    • Jen Kleinholz says:

      I had a bit of a stomachache because the title of the article sounds a bit like clickbait, but I think I have explained the relation of the "damage" and I hope the information helps with the personal assessment ... unfortunately I cannot test series with 100 iPhones with and without MagSafe, that's why such an assertion is always on shaky ground.

  6. Makayla Burby says:

    I've been using an IPhone 12 Pro Max for eleven months. When I returned it it was at 80% battery health. The only difference was that I used a regular charger the whole time. That leads me to wonder whether it is the iPhone 12 models in general that have such bad batteries. I am looking forward to your opinion.

    • Jen Kleinholz says:

      That could be an explanation, but the fact is that MagSafe charging heats the battery more than "normal" charging with the cable. Did you charge your iPhone 12 Pro Max with a USB-C to Lightning cable? These also deliver a lot of power if the right power supply is attached and then the battery is almost as warm as with MagSafe. That would be my only explanation ...

  7. Manny Kricke says:

    Hi, I would like to sell my iPhone X (2017 model). Always charged via USB-A, mostly at night. It now shows a maximum battery capacity of 81%. Is that okay? And maybe one more question (even if you don't pass directly). What can I charge for such a device? 256 GB, color black, tip-top condition, always in the Apple flip-up case and protected with bulletproof glass. I would be happy to get some hints. I had thought of at least 320€ - completely wrong?

    Thanks and Greetings
    Manni

  8. Christian Schietzel says:

    Very interesting post. Your arguments coincide with my observations on my IPhone 12 Pro.
    Had a MagSafe charger and charged the iPhone every night at the bedside table via the MagSafe charger. After two to three weeks, the battery capacity has dropped from 100% to now only 96%. The IPhone is now about a year old. I'm really unsure whether it's generally bad batteries in the iPhone 12 or whether the MagSafe charger has a large share in the loss of capacity!?

    • Jen Kleinholz says:

      I think you can always be unlucky and catch a bad battery in a batch. Not all batteries in all iPhone 12 models have to be bad. But I don't think you're doing the iPhone battery any good with daily MagSafe charging either.

  9. Phil says:

    And here lies the problem with the Internet:

    Any random person is spreading any and all misinformation and the poor readers who search the internet for needed (and most importantly correct) information are directed to the site unaware that they are being misled.

    You can't just mouth the words "scientifically proven" when all you have is a poorly performed "experiment" (where you drew a conclusion from temperature data that was actually statistically insignificant). Also, you never account for anything as crucial as a margin of error (which your examples would easily fall into).

    The rest of your "experiment" wasn't even done by you. It's just a bunch of hearsay from other parties.

    Finally, how can you "scientifically prove" something when there are so many variables that you never take into account? No control and test group. No double-blind study. Different people with completely different usage habits… oh yes, and different cell phone models.

    Instead, you're drawing false conclusions from shaky science. Next time just do your research - there are tons of websites out there with detailed information on the differences between wired and wireless charging and how much wireless charging affects your battery. Or simply link your readers to another page.

    • Jen Kleinholz says:

      Hey Phil! Thank you for your criticism. However, I did mention in the post that I'm not a scientist and that I'm using a website that has people who know about batteries talking about battery health and heat. And of course my experiences are only an isolated case - but the technical connections (MagSafe warms up the battery more than charging via USB-A-to-Lightning cable) are undeniable and technical. So I don't see any incorrect information in my article, just the indication that MagSafe charging is more beneficial to battery health than wired charging with lower amperage. And, of course, anyone can charge their iPhone however they want... I charge mine with the MagSafe every now and then because it's convenient.

  10. Peter William says:

    Oh my God!
    Jens, you are my savior. You opened my eyes!

    My body temperature has always been 37,2°C and I often enough have my iPhone in my trouser or shirt pocket. It's not much cooler there either.

    And if I meet a pretty girl, it can even get 0,3°C warmer in her pants.

    I only destroy my cell phone by having circulation and metabolism.

    I'll be eating more ice cream now and will change sides of the street if something feminine comes up. Also, I'm blowing my pants every few minutes now...

    • Jen Kleinholz says:

      Hi Peter! I'm glad that someone is finally taking my advice seriously. My tip for the trouser pocket: There are such cool packs at the pharmacy. Since I've had these in my pants, battery health has actually increased by 3 percentage points. I was already thinking about putting on rain pants and throwing ice cubes in my bag. I think Apple didn't make the iPhones waterproof for nothing. ;-)

  11. Wolfgang Wiegman says:

    Hello
    A supplementary question: what about wireless charging via devices from other manufacturers? Among other things, I think of cars that often have this charging option today. My car has that too, but I prefer a cable to the USB port that is also available. Is that necessary or can I also charge my iPhone wirelessly without any problems? If so, is it faster over the cable?

    • Jen Kleinholz says:

      Hello Wolfgang! Of course, that depends on what the manufacturers have installed. Most will not have a MagSafe charger inside and will rely on "normal" Qi charging. The iPhone then charges with 7,5 watts. If you have a wired charging port, it depends on what kind it is. If it's the standard USB-A, which is probably what most cars have on the radio, then the iPhone won't charge quickly. If you're looking for the fastest option, get a USB-C car charger adapter with Power Delivery (such as this one from anchor eg) and a USB-C to Lightning charging cable (like this one from Syncwire). This means that you can not only charge an iPhone quickly in the car, but also an iPad.

  12. Max says:

    Hello, does using "fake" (cloned) magsafe accessories affect battery life more than the real one? For example, I am referring to the aliexpress magsafe duo clone or the magsafe charger clone.

    Thank you

  13. Raphael says:

    Thanks for the explanation. I have had an iPhone 2020 Pro Max since September 11, which I have charged almost exclusively with my old iPhone charging cable, and the battery was always between 99-25% 80% of the time.

    After exactly 1,5 years, I now have a maximum battery capacity of 98% and always get through the day with an average maximum battery consumption of 50%.

    Three days ago I bought an iPhone 13 Pro Max, which is already 6 months old, but is still at 100% (maximum). I found the idea of ​​MagSafe very interesting, especially since it's easier to use your phone while it's charging. Thanks to you, however, I will keep my hands off it, as I would like to have more of the battery.

  14. Thomas says:

    So I have my 12 Pro Max on the induction charger in the car every day because of the Blitzer app. Am now at 87% battery and have had the 12 for 15 months. I think you can live with that, right?

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