Apple Watch Series 4 Teardown: 20% Less Battery Capacity, Hidden Barometric Sensor, and Streamlined Internals [Updated]

iFixit has completed a teardown of the Apple Watch Series 4, providing a look inside a larger 44mm model with LTE.

ifixit apple watch series 4 teardown 1

Image Credit: iFixit

The repair experts believe that while the original Apple Watch was awkwardly layered together and used too much glue, the Series 4 lineup feels "much more thoughtfully laid out," likening it to the iPhone 5.

Apple pundit John Gruber has compared this to the leap in design brought by the iPhone 4, and we might even go a bit further and call it an iPhone 5: a device that knows its priorities, and wants to look as elegant inside as out.

At first glance, the internal design of Series 4 models looks more or less the same as previous models, with the battery and Taptic Engine taking up most of the space. Dig deeper, however, and the changes become evident.

ifixit apple watch series 4 teardown 3

Image Credit: iFixit

Teardown highlights:

  • 1.12Wh battery in the 44mm model, which is 20% less capacity than the 1.34Wh battery in 42mm-sized Apple Watch Series 3 models.

  • A thinner and longer Taptic Engine, but iFixit says it still takes up a lot of space that could have gone to a larger battery.

  • The barometric sensor may have been relocated to the speaker grille for access to the outside atmosphere. The sensor had its own dedicated hole beside the microphone on Apple Watch Series 3 models.

  • The new Apple S4 chip is secured only with screws, whereas the processor is also "fiercely glued" in previous Apple Watch models.

  • The golden ring is likely a streamlined antenna system, as iFixit says it has not seen the usual fiddly brackets or golden gaskets.

  • The entire rear casing pops off more easily.

  • The display is not only larger, but also thinner.

iFixit says the Apple Watch Series 4 is nearing iPhone levels of repairability, with the highly-glued display being the primary remaining obstacle. Beyond that, they say the battery is straightforward to replace.

ifixit apple watch series 4 teardown 2

Image Credit: iFixit

All in all, the Series 4 received a "solid" 6/10 on iFixit's repairability scale, with 10 being the best possible score. That's the same repairability score iFixit gave the iPhone XS and XS Max in its teardown of those devices.

Update: A previous version of this article said Apple Watch Series 4 models have 4% more battery capacity, as iFixit mentioned, but that was based on comparing a 44mm Series 4 model with a 38mm Series 3 model. 44mm and 40mm Series 4 models actually have 20% less battery capacity compared to 42mm and 38mm Series 3 models respectively, although Apple says battery life remains up to 18 hours.

Related Roundup: Apple Watch Series 6
Buyer's Guide: Apple Watch (Caution)
Related Forum: Apple Watch

Top Rated Comments

AngerDanger Avatar
37 months ago
It’s always awesome to be reminded of the fact that these are tiny computers strapped to your wrist. Each one is probably more powerful than the computers used to render dinosaurs in Jurassic Park.

Score: 14 Votes (Like | Disagree)
donster28 Avatar
37 months ago
What a beautiful piece of engineering!
Score: 13 Votes (Like | Disagree)
Christoffee Avatar
37 months ago
Amazing tech. How far we've come from my Spectrum and Amiga days!
Score: 9 Votes (Like | Disagree)
Nozuka Avatar
37 months ago
Just remove the Taptic engine and you got more batetery :confused:
but we need the taptic engine to get notifications without sound.
Score: 7 Votes (Like | Disagree)
barjam Avatar
37 months ago
Of course there is waterproof. Anything made out of materials that contact with water doesn't affect is waterproof. The spoon I am currently holding is waterproof. Anything completely encased in material that isn't affected by water is waterproof. Encase something in (originally molten) glas and it is waterproof. With the right glue, you can waterproof a lot of things.

One can distinguish between seals that can be opened and closed and something that is sealed by filling a gap with a material that is liquid originally and thus can enter all nooks and crannies. In particular with water, due to its surface tension, if a capillary connecting the inside with the outside becomes small enough, it is hermetically sealed (of the course the surface tension translates into capillary pressure which then has to be compared to the ambient pressure, but if we limit ourselves with ambient pressures a human can survive in that is a very attainable limit).
Obviously we are talking about devices here and not spoons, rocks and stuff stuff like that. But if we are going to be absurd that spoon you mention isn't water proof (eventually stainless will corrode, it is just resistant) and the glass encased thing you made up would shatter at depth if there were any voids whatsoever.

Currently there is no industry standard in order for a device to classify as waterproof and thus "waterproof" can not be claimed as a product feature. Even things like dive watches/computers/etc are merely water resistant.
Score: 4 Votes (Like | Disagree)
Eriamjh1138@DAN Avatar
37 months ago
If the watch is waterproof and dustproof how does air pressure get to the barometer?
The barometer senses pressure, not dust and water. iFixit says they put it behind the speaker, open to the air.
The sensor is waterproof and dustproof. It means it is not damaged by water and dust. It doesn't mean it doesn't get wet or dusty.
Score: 4 Votes (Like | Disagree)

Top Stories

Pro Display XDR Yella

Apple Working on External Display With Built-In A13 Chip

Friday July 23, 2021 9:37 am PDT by
Apple is developing an external display that includes an A13 chip with Neural Engine, according to a new rumor from 9to5Mac. The A13 chip with Neural Engine would presumably serve as an eGPU, though details are light at this time. Having a CPU/GPU built into the external display could help Macs deliver high-resolution graphics without using all the resources of the computer's internal chip....
iOS 14 on iPhone feature emergency

Apple Releases iOS and iPadOS 14.7.1 With Fix for Touch ID Apple Watch Bug

Monday July 26, 2021 9:48 am PDT by
Apple today released iOS and iPadOS 14.7.1, minor bug fix updates that come just a week after the release of iOS 14.7, software that introduced new Apple Card features and support for the MagSafe Battery Pack. The iOS and iPadOS 14.7.1 updates can be downloaded for free and the software is available on all eligible devices over-the-air in the Settings app. To access the new software, go to...
discount m1 macbook yellow

Deals: Shop Record Low Prices Across Apple's Full MacBook Pro and MacBook Air Lineup (Up to $499 Off)

Friday July 23, 2021 8:23 am PDT by
Apple's MacBook Pro and MacBook Air lineup is seeing all-time low discounts across the board today, including the 2019 16-inch MacBook Pro, 2020 13-inch MacBook Air, and 2020 13-inch MacBook Pro. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the site running. 13-Inch M1...
iphone 12 pro gold

Report: iPhone 14 Pro Models to Feature Tough Titanium Alloy Chassis

Monday July 26, 2021 1:12 am PDT by
Next year's "iPhone 14" series is expected to feature high-end models with a new titanium alloy chassis design, claims a new investors report by JP Morgan Chase. According to the report, the use of titanium alloy will be one of the biggest changes to the case design in the 2022 iPhone series, and Foxconn will be the exclusive manufacturer of the titanium frames for the high-end models....
FaceID iMac REREREREMIX

Gurman: Face ID on the Mac Coming Within a 'Couple of Years'

Sunday July 25, 2021 7:09 am PDT by
Apple plans to bring Face ID to the Mac within the next "couple of years," respected Bloomberg journalist Mark Gurman said today in the latest edition of his Power On newsletter. In the newsletter, Gurman says that he believes Apple's ultimate goal is to shift all of its products to Face ID, including the lower-end iPhones such as the iPhone SE and the iPad Air, which feature Touch ID....
airpods 3 gizmochina Feature

AirPods 3 Rumored to Launch Alongside iPhone 13 at Expected September Event

Friday July 23, 2021 12:54 am PDT by
The third-generation AirPods will likely launch at the same event revealing Apple's upcoming iPhone 13 lineup, according to a report from DigiTimes, which makes the claim citing sources familiar with the matter. The report as a whole echoes previous reporting that production of the third-generation AirPods will kickstart in August, meaning a launch shortly after can be easily expected. DigiTi...
imac with accessories

Larger Redesigned High-End iMac Rumored to Launch Next Year

Monday July 26, 2021 3:45 am PDT by
Apple's larger redesigned iMac will arrive sometime in 2022 rather than later this year, according to the leaker known as "Dylandkt." On Twitter, Dylandkt claimed that Apple's "high end iMac" is not expected to release in the fourth quarter of 2021 alongside Apple's "M1X Macs" – a reference to Apple's redesigned MacBook Pro models – because "Apple simply does not want their devices to...
apple bitcoin hack

Is Apple Really Buying Bitcoin?

Monday July 26, 2021 3:07 am PDT by
A large number of websites and posts on social media are stoking rumors that Apple has purchased $2.5 billion worth of bitcoin in the company's first move into cryptocurrency, but is there any validity to the claims? Many people are citing the fact that Apple was looking for a Business Development Manager with experience in alternative payments, including cryptocurrency, earlier this year as ...
apple mac business page

Apple Shares 11 Reasons Why Business Users Should Choose Macs

Monday July 26, 2021 11:35 am PDT by
Apple today updated its Apple at Work website with a new section dedicated to the Mac, which offers up 11 reasons why "Mac means business." On the webpage, Apple highlights the M1 chip as the number one reason why business users should choose a Mac, offering up an M1 overview [PDF] that explains the benefits of the M1 chip. The information isn't new, but it does provide a look at all of...
magsafe battery pack iphone 12 mini

Top Stories: Hands-On With MagSafe Battery Pack, iPhone 13 Always-On Display?

Saturday July 24, 2021 6:00 am PDT by
Apple's new MagSafe Battery Pack is now available, and we went hands-on this week for some early impressions of the new accessory to get more battery life out of Apple's iPhone 12 lineup. Subscribe to the MacRumors YouTube channel for more videos. This week also saw a number of rumors about the upcoming redesigned MacBook Pro models, the iPhone 13 lineup, the next-generation iPad mini, a new...