Teardown of Apple 40W dynamic power adapter with 60W max • Hacker News Board

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#111

Post by red369 » Sun, Sep 21, 2025, 10:00 AM UTC

SomaticPirate wrote: post #47

ryukoposting wrote: post #34

This is very cool, I might actually get one to charge my laptop. That being said... I can't be the only person who consciously avoids fast-charging my phone. My whole apartment is full of wireless charging pads intentionally plugged into weak chargers (wireless charging avoids putting wear on the USB port). 60 watts can't possibly be healthy for a battery small enough to fit into a phone.

I believe current battery technology is optimized for fast charging. You are incurring damage every time your battery goes below 20% or exceeds 80% (see current EV charging recommendations). Even LinusTechTips did a video that showed the length of charging doing more damage than fast charging. For the concern about thermal damage, most phones will throttle their charge if they become too warm. Personally, I feel my w…

Thanks for bringing up that LinusTechsTips video - I'll try and track it down. I would not have expected that conclusion. I've already said in another comment on this thread that I'd expect the opposite!

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#112

Post by lxgr » Sun, Sep 21, 2025, 10:06 AM UTC

coder543 wrote: post #74

Gigachad wrote: post #66

Earlier quoted context omitted.

There was some speculation that chargers would need the AVS spec to full speed charge the new iPhones, rather than just any USB-PD. Has that been tested yet?

This post[0] seemed to be the main source of confusion, but it has since been updated at the bottom to apologize and say it wasn’t true. You don’t need some kind of special charger. [0]: https://9to5mac.com/2025/09/13/iphone-17-pro-fast-charging-p...

That said, the Apple 40W charger does support AVS according to the fine print on its exterior:

https://photos5.appleinsider.com/gallery/65105-135925-Dynami...

I could definitely see maximum sustained charging speeds only being sustained with optimal supply voltages, which minimizes converter loss (and thereby heat, which is the actual limiting factor for fast charging these days) in the phone.

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#113

Post by lxgr » Sun, Sep 21, 2025, 10:10 AM UTC

Reason077 wrote: post #13

Hopefully Apple releases a UK version of this adapter soon. The design looks very similar to my beloved Apple UK 20W charger [1]. I’d buy a 40-60W version in a heartbeat! [1] https://www.amazon.co.uk/Apple-20W-USB-C-Power-Adapter/dp/B0...

Wow, that does look very neat for an Apple charger. The prongs are individually foldable, right?

I wish there was something like this for Europlug chargers. Ironically, the most compact USB adapter for me so far is one with a US plug, combined with an US-to-Europlug adapter, which can be made very compact, but seem a bit risky at 220V, given that US plugs expose the prongs while connected.

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#114

Post by jwr » Sun, Sep 21, 2025, 10:19 AM UTC

arvinsim wrote: post #97

SomaticPirate wrote: post #47

Earlier quoted context omitted.

I believe current battery technology is optimized for fast charging. You are incurring damage every time your battery goes below 20% or exceeds 80% (see current EV charging recommendations). Even LinusTechTips did a video that showed the length of charging doing more damage than fast charging. For the concern about thermal damage, most phones will throttle their charge if they become too warm. Personally, I feel my w…

I agree. I started using wireless charging with my iPhone 15 Pro Max. After a year of use, I am already near the 80% max capacity. My previous phones never even got below 90% in their lifetime.

Are you using high-power wireless charging? Does your phone heat up significantly?

As a counterpoint, I've been using low-power wireless charging (5W adapters) with my phones for the last several years (three phones at least). The battery degradation was minimal, I was able to pass my phone to my kid after 3 years of use with near perfect battery.

The key here is to prevent heat buildup.

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#115

Post by bArray » Sun, Sep 21, 2025, 10:21 AM UTC

Amazing tear down and such compact design, but it's such a shame that these devices are glued together. Every time you see a glued device, just think "future e-waste".

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#116

Post by [deleted] » Sun, Sep 21, 2025, 10:31 AM UTC

ssl-3 wrote: post #43

rr808 wrote: post #16

Is there a way to slow down these high power chargers? Sometimes I want a fast charge but mostly I want slow to getting hot. I realize overnight charging phones are smart enough to do this but otherwise seems to be impossible without having two different chargers.

The charging smarts are always in the phone, and always have been. Just because a USB port has 15 or 30 or a gazillion Watts available doesn't mean that the phone is required to consume that much. Similarly, the wall outlets in your house may be able to supply a couple of thousand Watts -- but that doesn't mean that a device plugged in is required to use all of that. And batteries can charge pretty fast these days. M…

[deleted]

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#117

Post by [deleted] » Sun, Sep 21, 2025, 10:34 AM UTC

0_____0 wrote: post #28

analog31 wrote: post #18

Earlier quoted context omitted.

The device being charged controls the charging current. Typically for smaller gadgets, a single resistor connected to the charge controller IC sets the current. Bigger things like laptops may be more sophisticated.

Re: more sophisticated USB-PD now has a standard for having sink devices request a particular current from the charger, meaning that you could actually remove a converter from the sink device side, because with a programmable source, the current limiting happens on the power supply side. Cool stuff especially for small electronics like wearables. Generally though if you want to charge with USB-PD and accept all kinds…

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Re: Teardown of Apple 40W dynamic power adapter with 60W max

#118

Post by arccy » Sun, Sep 21, 2025, 10:35 AM UTC

copperx wrote: post #92

jstrieb wrote: post #69

This teardown is great! At my work, we have an X-ray machine for PCB reverse engineering. On Fridays we throw in random stuff from around the office, and sometimes make videos about what we find inside. A few weeks ago we released an X-ray teardown of several other, older chargers. Very interesting to compare with these fancy new ones! https://youtu.be/4h4qabPsPfI

Would a CT scanner work better for your use case? (ignoring cost)

don't those have giant magnets....

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#119

Post by QQ00 » Sun, Sep 21, 2025, 10:42 AM UTC

qnleigh wrote: post #67

Why do so many websites disable pinch-to-zoom for mobile users? This page is full of interesting close-up photos, but at least on my Android phone, I can't zoom in to see any of the details. Who benefits from disabling this feature?

turning the desktop mode on in the browser always worked for me to bypass such limitations on the mobile browser. just tested it and the pinching and zooming works fine.

Re: Teardown of Apple 40W dynamic power adapter with 60W max

#120

Post by tecleandor » Sun, Sep 21, 2025, 10:42 AM UTC

arccy wrote: post #118

copperx wrote: post #92

Earlier quoted context omitted.

Would a CT scanner work better for your use case? (ignoring cost)

don't those have giant magnets....

That'd be an MRI.

A CT is, simplifying, an x-ray machine that takes lots of images in slices, then analyze them with certain algorithms to reconstruct 2D and 3D images of the interior of the 'subject'.