How Wireless Charging Works and Why It's Terrible 

What I find most frustrating is that if you're going to go as far as using magnets to ensure "perfect" alignment for the coils, you might as well use them to align metal contacts. Same convenience as "wireless" charging, but with the efficiency of wired charging.

My dad always complains about his phone getting hot when wireless charging in his car and no matter how centered I align his phone, it'll always gets hot and his phone will stop charging to control the thermals. But this video and illustration of Tesla solution of slapping so many coils might be the problem but my dad resorted to wired charging in his car anyway.

I didn't realize the power loss or temps were so high. I'm going back to the ol' wire. Much appreciate the video.

It’s terrible until the charging port doesn’t charge and the phone is able to stay alive for another year thanks to it.

Glad to see this video. I worked in a phone store, where I would continuously correct everyone I worked with including my manager, that no, wireless chargers were not in fact better for your battery longevity and to stop telling that to the customers that weren't knowledgeable enough to know otherwise, so they had to trust our experience and advice. I quickly realized that they either didn't choose to believe me or do any research themselves before making recommendations, or didn't care because selling an additional $40-$70 charger as essential for phone health was part of their commissions. I remember them saying they "trickle charge" like it was some feature of the wireless chargers when it's just something most modern phones do. Mind you I still sold a decent amount of them being completely honest with people, as there are still use cases even without a claim of better battery longevity. Convenience, an alternative if your port fails, to name a few. This is one of the many reasons I chose to move into the electronic repair business instead, a lot more honesty there compared to retail phone sales.

This is exactly why Apple never released AirPower, even Apple realized so many coils in a wireless charger is too much heat to manage properly. Honestly it’s good they pivoted to MagSafe and the Qi 2 standard adopted the same tech.

Living in a subtropical country, 30°C temperature feels almost like late fall or early spring. It's usually 40-42°C during summer and 35-38°C most of the year. So our phone batteries are constantly getting degraded even without charging.

At <a href="#" class="seekto" data-time="163">2:43</a>, the wired connection is represented by a dashed line, the wireless connection is represented by a solid line... an interesting subversion of expectations.

Most phones have a feature to disable fast wireless charging which significantly decreases heat and also slows down battery charging overnight to about 3 hours which can actually help reduce wear

Appreciate you for sharing your conclusions at the *start* of the video, and making the video only as long as it needed to be to illustrate your conclusions (unlike most youtubers who intentionally breadcrumb the conclusions to force you to watch through their drawn out videos). Liked and subscribed!

I’ve gone back to wired

I work in a phone store and always recommend wires over wireless charging. It's so much better

Great video! Thank you for sharing good info with tests and data to back it up! I appreciate the effort that you guys put into teaching things that benefit us users! Keep up the good fight!

Appreciate the testing. I was hoping there was more tests about how much batteries degrade with higher temperatures, but that would take a huge amount of work and data.

I really love wireless charging for slow charge overnight - I even connected my charger to slow power adapter on purpose - to not allow it to fast charge. What i really like os that I don't have to plug in a cable, not only does it look nice, but also does not wear the USB-C port. So you just have to use it in a smart way.

commenting to support these findings and data. love your work.

Finally someone competent pointing out this waste. Thank you!!

Finally someone say something about this, been feeling disturbed for a long time with people glorifying wireless charging over fast charging. Thanks iFixit for mentioning this!

I'm glad to see someone calling this out. I wish this were more widely known so people could make informed choices to not purchase or use wireless charging.

very nice video, quick and compact from the start on

<a href="#" class="seekto" data-time="79">1:19</a> the cable is right there! you just added an extra step!

I had a feeling that was the case. Thanks for the testing.

Thank you for this info! Keep it up!

Never had a phone with wireless charging and never needed it. Seeing people mark down phones for not having it, especially budget phones, makes my eyes roll.

I like to use USB-C magnetic adapters as an alternative. You get the benefits of not having to be accurate with plugging in (plus you don't wear out the USB port), but retain the benefits of wired charging. Such functionality should really be added to the USB spec.

I have to say that I always thought that wireless charging was pretty worthless until I damaged my charging port out of warranty. I keep my phone for at least 3 years before upgrading and wireless charging has saved me from an early upgrade. With that being said I would still give it up in a heartbeat for a rear mounted fingerprint scanner.

<a href="#" class="seekto" data-time="66">1:06</a> try it with budget phones. i have seen like 40-50c on cheaper phones.

I use wireless charging out of convenience since I'll need to plug and unplug frequently. I always place it under a small desk fan pointed at the phone. It keeps it nice and cool even after charging for over an hour - I imagine the battery temperature is kept a bit cooler from this. For overnight charging it's a 5 W charger to minimize heat. No need to charge from 20% to 80% in 30 minutes when it's going to be plugged in for 7 more hours anyway.

It's all about compromises. The ease of being able to pick up the device and put it back to charge in a second is handy for example when you're doing many short trips in a car, and would rather not break the charge port. There's no point in choosing wireless over wired when the device is charging overnight.

Happy to see more people talking about this!

Brilliant! We definitely need more educating videos like those! People need to learn best practices to avoid environmental impact.

I've been waiting for someone to make this video for years!

Just use a “slow” 5W wireless charger for overnight charging. It’s much better for your battery to slowly charge (after a deep cycle preferably) than a super fast charge on a wire or a powerful wireless charger

Having used a 5w Anker wireless charging pad for many years, it never manages to create enough power to make my iPhone get even barely warm 😂 Wired charging still seems to make the phone get noticeably warm, though I can’t decide if the slower wireless charging is overall better for the battery or not. Based on my son using my old 12 Pro Max which is still on mid 80’s for battery health, I’m inclined to think slow wireless charging is no concern beyond energy waste….possibly balanced by a phone which still has great battery health and life.

I almost always use wired, however it is useful to have a MagSafe cable around for when water gets in the charging port

I’m using baseus magsafe stand to charge my iPhone. Yes it gets longer to charge but it doesn’t get that hot as charging by wire. In my opinion mag safe magnets are the best way to perfectly align your phone to wireless charger.

Loved the video. Would like to see how it compares with wireless charging stations that have fans

Apple Magsafe kinda nailed it. Get the right magsafe stand and you really don't worry about charging. Even when I'm drunk I can wave my phone over my charging stand and it'll grab my phone outta my hand.

Great to see some solid numbers on charging efficiency and thermals. I’ve heard claims about wireless charging degrading battery life for as long as I’ve seen wireless chargers. But I’ve never seen people get into details and produce numbers. Are the temperature tolerances on lithium ion batteries that low? 35 degrees Celsius is stuff I see often on holidays and are quite common in some parts.

I've charged my Sony Xperia 1 IV wirelessly for almost two years now without issue BUT that being said I've only charged at 5w max to keep temperatures down. If i charge at 15w the phone becomes quite toasty (battery temps close to 40C). Wired 30w charging pretty much never exceed 30C but wireless charging at 5w is only a degree or two above room temperature. It's nice to just drop the phone on a pad after work and if I need faster charging wired is always an option.

I just like wireless charging because it's easy. I just set my phone down on the pad and it recharges. And I have CPU-Z on my phone to check the health and temperature of the battery. It doesn't get above 26 or 27 C.

I have a Galaxy S22U and wireless charge with a 5W charger. The battery does not get anywhere near 30C. It's even recommended to use wireless charging at 5W at night when the phone is of. Your phone being off is what helps prevent it from getting hot, and battery degradation.

Side note: Thank you for all your videos, they’ve helped me pay the bills fixing people’s stuff for many many years now ❤

Could you test the MagSafe duo? Specifically I’m interested in knowing what battery temps and energy efficiency are like when a phone and watch are dropped on it

i only ever use wireless charging overnight with a 5w outlet so im sure it charges very slow and doesnt let it get that hot

They called it wireless but i can still see the wires

This may sound like something with hindsight. I felt increased battery degradation when using wireless charging pad after I got my iPhone 11 in 201. The battery degradation went crazy. I initially guessed Apple may somehow use batteries of lower quality for iPhone 11 series but I was not sure. Happy that IFixit has cleared it out.

I’ven been a big fan of magsafe charger. Been using almost exclusively on my 13 pro max since its launch and I do not see any extreme battery wear, even with the frequency I charge my phone due to how much i use it. Must add that i live in a pretty cold region, with summer with >25° temperatures only lasting for a couple of weeks. When its hot i definitely feel my phone getting toasty no matter how I charge it. One solution I used last year was to put the phone in a thin plastic container, add a thin layer of water and then connect the magsafe under the container.

I always use wireless charging when charging my phone during the night, it's waaay to convenient not to, and cable if I need to top it up during the day - Could be worth pointing out the wear and tear on the USB-port by constant having to plug it in, one of the reasons I prefer wireless charging for my phones, an S23 Ultra as of now.

wireless charging is like freezing some water , then bringing that forzen ice above your head , heat it using a lighter , and then drinking the melted waterdrops. i honestly never understood the point behind wireless chargers.

This explains why my magnetic Anker warmed up my iPhone that I didn't like, but it still was better than the 5 euro Hama without magnet that actually makes the phone hot to touch.

Awesome video :D I am wondering and often thinking about if it is true that chargers communicate via the cable with the attached devices. Like "Hey device XY, I can charge you with 30 Watt, N Ampere and K Volt. What do you accept? Do you also happen to be an Apple-Device?" or that there are mechanisms that ensure a safe charging, like protection against overheating or pumping out a to high / low current. Do you maybe already have a video about this topic?

Something that should be mentioned in defense of wireless charging is that wireless charging prevents wear and tear on the charging port; which (unfortunately) for many phone models is not as easily replaced as the battery, if it's even replaceable at all. I've had to replace several otherwise working phones in my life due to the charging port being worn out to the point it would not consistently charge.

69% battery on the first phone shown, nice

Very informative, and that's why I found a MagSafe charger with an integrated fan and to keep the phone cooler during charging, before I saw this video. and it's definitely important to know about misalignment, meaning I see large charging pads all over the place these days and now I don't use it.

Thanks for sharing this info.

I never understood the point of "wireless" charging. You still have a wire that goes all the way to the phone PLUS a big puck underneath it PLUS it's less efficient PLUS before mag-safe you couldn't use your phone while charging it wirelessly since it had to be on the pad. The only time I've ever used wireless charging was when I wrecked the ports on some older phones--it's great to have as a second option, but not as a first.

I think this is an example where the inefficiencies and battery degradation are absolutely worth it. Especially if you use Magsafe or Qi2 chargers, and actively cooled ones when possible. The convenience of Magsafe/Qi2 especially is incredible for phone mounts on desks and in cars to keep you topped up throughout the day and keep your phone easily accessible. Also, every phone I've ever used has had charging issues eventually before wireless charging (even my first USB-C phone). With my last phone, I used wireless charging almost exclusively and saved my USB-C port from the same fate. Videos like this are great to inform consumers about these trade-offs and what to look for to avoid the worst cases, but I definitely think this video is a bit overly critical of the technology.

I thought I was tripping when I used Wireless Charger and my phone got really really really hot. Now it makes sense. Glad I stopped using those years ago.

wanted to know how it works and found a video explanation of just that an hour later. eggcellent

Finally someone speaks about this, thank you! I am not using wireless charging exactly for these reasons for a few years already. When I tried it, I did not find it any more convenient than plugging the phone in.

I use a wireless charging stand for iPhone and apple watch. They are always on it. I never have to bother about checking battery and charging before going out. When I take my phone, it’s always full. The same goes for the watch. I will change my phone faster than the battery dying.

Sony Xperia 3 actually had a magnetic interface on its side that allowed for the convenience of "wireless" charging with the advantage of actual electric contact that avoided the loss of wireless charging. If only we can establish a standard interface using this concept for phones.

thanks for this video. I was looking for wireless one but after this I'll stick to wired ones.

this is why I do not care if phone have a wireless coil, I never used it anyway

@<a href="#" class="seekto" data-time="165">2:45</a> use large bold font for your labels and axis numbering, even at 2160p we have to squint to see this.

Is a lower Wattage wireless charger better for an overnight charge? I usually leave it there when sleeping. On my S23U, it takes around 3h30 to charge from 20% to 100%, but I never notice it getting hot. It's an IKEA charging pad, where the other end is a USB A connector.

Huh... I did not know the overheating is such an issue! Thanks!

Dang that's HOT

Thank you iFixit! Just a small geeky fix: it’s degree Celsius, not centigrade. This is not the same scale and I think you are using Celsius thermometers.

Question about your 65W USB-C GaN iFixit Fast Charger. Does it ONLY have one output? How can I charge multiple devices at once using this?

I have few charging cables which have a separate tip connected by magnets. The tip stays in my device and when it needs charging, snapping it to the cable is easy and fast. I use them on devices that need charging daily and i dont want to wear out their port. Do these magnetic charging cables have any downside as opposed to normal cables?

And still Apple is heavily pushing for wireless charging while saying they removed the changer brick because they are a 'green' company

A wireless charger needs a small fan to keep the phone from overheating.

Now that we see crazy fast wired charging, it makes me question why there are people who see smartphones without wireless charging as a "deal breaker". I easily take super fast wired charging over wireless charging all day.

<a href="#" class="seekto" data-time="79">1:19</a> That's why the recommended power for wireless charging is at 5 watt, leave them charging wirelessly during your bed time.

You mean the best way to improve efficiency is by not being lazy?

To be fair, the wireless charging pads on this video is on the budget side. More expensive and even prorpietary solution like Oppo's Airvooc wireless charging pad has dual coil for maximum efficiency and an active cooling fan working in tandem with the phone's pmcs to control the temps. Even then it's still much more inefficient compare to just plug a cable in. Which is why super fast charging through cable is superior, and a modular charge port design should be made a requirement by law

I like wires myself but the option is interesting to me.

It's worth mentioning the one advantage of wireless charging - a lack of an opening or port that can become damaged or broken from prolonged use or exposure to foreign material. Though I still only bother with using it as a backup because it's so slow. I tapped directly into the USB-C port for my car's built in wireless charger and it went from a 4 hour trickle charge to a 40 minute rapid charge.

Prevents loss of cables from damage, screw the energy losses.

Can we stop calling it wireless charging and just call it induction charging? When real wireless charging arrives, what will that be called?

I used wireless charging twice when I got an iPhone 12 several years ago. Haven’t touched it since. I already was aware of the lower efficiency and power loss from charging over a distance in general but was extremely unimpressed at how hot my phone became compared to how long it took to charge. And on top of that you scale it across several billion units, it uses a lot more of the precious copper to do the same exact thing but worse.

It's all about heat management. I've switched back to a low-wattage charger for overnight use and I'm utilizing the 80% charge option, since I can essentially charge my phone throughout the day at work. Occasionally, I switch to auto mode if I'm on a hiking trip or engaged in similar activities. My 14 Pro Max still retains 100% battery health. I'm somehow addicted to hold my batterylife at a constant level. It feels like an achivement :D

Ever since I switched to using iPhones, I really enjoy the convenience of plopping down my phone on my magsafe compatible wireless chargers. I don't mind the slower charging time as I put it there for the night. However, if I need the charge to be done faster, I will most certainly plug my phone into a faster wired charger.

i know Wireless is worse than wired, but it is so much more convenient to park the phone without thinking about cables (beside the one in the charger)

They should just use the magnets to align metal contacts like they used to.

Nice, though more info in video on why the battery gets so hot would be nice. If I remember it is mostly because the battery is right on top of the receiver coil that is getting hot (inefficient) than the battery somehow heating itself by lower/inconsistent amperage, and -- at least the battery heating -- could be mitigated with in creased distance from battery to coil... of course, not much space in a phone, and long cables to heavy batteries segregated to one end of the car is a new set of challenges.

You completely ignored a big reason for wireless charging: avoiding having the wired connectors wear out. The energy waste is not likely to be more significant than the physical waste of broken phones, repaired or not.

The energy wasted over a lifetime of wireless charging is still less that used in a single car ride. Perspective is important here.

Just build a fan into your wireless charger like OnePlus does. The battery degradation and temperature increases is negligible.

What about the magnetic usb connections where you leave a discreet plug in the phone socket and connect when necessary to a charging cable using its own magnetic connector? Obviously that’s not wireless in the same sense but as it’s accessing the battery via the phone’s usb socket is it more likely to help preserve the phone’s longevity?

As long as people still "mine"crypto and waste massive amounts of power for nothing, I'll keep using my less efficient wireless charger. The 40C temp is not that bad actually, I was expecting more. That's not much more than human body temp and I live where it is normally 35C and above anyway. The "increased" temp is a moot point and have to disagree with the warning about it here.

Having a redundant method of charging if you’re charging port goes bad is not a bad thing.

I really only use wireless charging for two things. I have a MagSafe charging phone mount in my car with a built in cooling fan for driving. I also have a wireless charging pad beside my bed so I can charge my phone at night, but that’s connected to a 5 watt power supply for low-speed charging.

This is the effect of normies

*Coughs in Taylor Swift's jet usage.*

Thank you so much for making this video. I have been arguing for yeas about how bad wireless charging is from an efficiency and battery perspective. It's slower than wired when you need speed, it's less efficient when you wanna save energy, and it will degrade your battery faster. Yet people still see is as an essential feature, for some reason...

I remember a precursor of the now-ubiquitous Qi charger, the Palm Pre "keystone" (?). My very first foray into modern electronics hacking was modding a Galaxy Nexus to connect the 5 volts from the charging coil removed from a spare Palm Pre back cover to the back of the pogo pins intended for docks. It worked, but boy was that thing toasty, and it probably wasn't good for the battery module to be squished a little bit more with a coil right next to it. Thankfully it never blew up like the old Galaxy Note did. Every time I've tried a "new innovation" for wireless charging, it always heated up the phone and its battery. It was especially bad when you tried using a wireless pad in a car during navigation, most of the time it would stop charging because of overheating, especially with newer Android releases that monitor temperature. So I stick to BigClive's recommendation: USB, 5 volts, low current. Use PD only if you have to get your phone charged NOW. Oh, and NEVER wireless charge overnight. You'd think a trickle charge overnight would be OK, but not when the battery is heated up.

Regarding power loss, whether you use a case, the material, and how thick it is will all further contribute to slower charging and a hotter phone. Most tests remove the case to eliminate it as a variable so your results will likely be a lot worse.