How Wireless Charging Works and Why It's Terrible

You’ve seen wireless chargers, the tech is now as common as the smartphones they power. But did you know that they come with a big catch? Today we go over the tech behind wireless charging and just how much it actually takes to get your battery full again.

Check out our blog on Wireless Charging!

Grab our 65W USB-C GaN iFixit Fast Charger!

Big thanks to Creative Electron for the x-rays they sent us!

Chapters
00:00 Intro
00:18 What to know about wireless chargers
00:36 How does wired charging work
01:11 How does wireless charging work
01:47 Wireless charging issues and some solutions
02:49 Worst Case Scenario of Wireless Charging
03:13 A look at the Tesla wireless charging platform
03:55 Final thoughts

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[YEdwardP]

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.

[Poorgeniu]

*UPDATE:* It seems that if you use wireless Android Auto or Apple Carplay, your phone will get hot and wireless charging just exasperates the thermals further.


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.

[NotCaptainToad]

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.

[jarboer]

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.

[MichaelLargent]

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

[ashfakuddinahmed]

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.

[EJPCRSKW]

1:56 Correction please. The efficiency problem is not in generating the electrical field. The underlying principle here is the transformer, and transformers can be extremely efficient. The problem is the poor magnetic coupling between the primary winding in the charger and the secondary winding in the phone. This could be _improved_ by ensuring correct mechanical alignment, and _not_ as per the Tesla solution of more coils. You could even let the magnetism do the alignment for you. Still won't be as good as a wire though.

[coder]

At 2:43, the wired connection is represented by a dashed line, the wireless connection is represented by a solid line... an interesting subversion of expectations.

[cywestbrook]

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

[zeux]

There is a power rectifier in your USB charger plug to convert 230V/120V AC to 5-20V DC, a power inverter to convert it back to AC in the wireless charger, and the induction coils in both the phone and the charger which only take and give AC current, while your phone needs DC, which means another rectifier. All of those components have a loss factor, especially the induction coils, which wastes power into the ether due to impedance or resistance.

[humanser]

They called it wireless but i can still see the wires

[judgemint]

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

[RainbowGin]

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

[TReKiE]

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.

[oplkfdhgk]

1:06 try it with budget phones. i have seen like 40-50c on cheaper phones.

[davidsanders]

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.

[bjornroesbeke]

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.

[tamwilfred]

This video seems to exaggerate the negatives of wireless charging. While it may produce some heat and potentially cause minor battery degradation, if it were truly detrimental, it wouldn't be a feature in modern smartphones. Consider the scenario of using wireless charging to incrementally charge the battery throughout the day. I maintain my battery between 20-80% and avoid leaving my phone on the charger overnight. Having used wireless charging since the early 2010s, I've observed no significant impact on my phone's longevity. It's worth noting that older Samsung wireless chargers included a built-in fan to mitigate overheating. I still use the older version, I think it was a 2018 or 2019 model.

[cookiesaregreat]

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!

[NathanTheZealot]

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.