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 11
Buyer's Guide: Apple Watch (Buy Now)

Popular Stories

2024 iPhone Boxes Feature

Apple Adjusts Trade-In Values for iPhones, iPads, Macs, and More

Thursday November 6, 2025 11:12 am PST by
Apple today updated its trade-in values for select iPhone, iPad, Mac, and Apple Watch models. Trade-ins can be completed on Apple's website, or at an Apple Store. The charts below provide an overview of Apple's current and previous trade-in values in the U.S., according to its website. Maximum values for most devices either decreased or saw no change, but the iPad Air received a slight bump. ...
Finder Siri Feature

Apple's New Siri Will Be Powered By Google Gemini

Wednesday November 5, 2025 11:57 am PST by
The smarter, more capable version of Siri that Apple is developing will be powered by Google Gemini, reports Bloomberg. Apple will pay Google approximately $1 billion per year for a 1.2 trillion parameter artificial intelligence model that was developed by Google. For context, parameters are a measure of how a model understands and responds to queries. More parameters generally means more...
iOS 26

iOS 26.1 Available Now With These 8 New Features

Monday November 3, 2025 5:54 am PST by
Following more than a month of beta testing, Apple released iOS 26.1 on Monday, November 3. The update includes a handful of new features and changes, including the ability to adjust the look of Liquid Glass and more. Below, we outline iOS 26.1's key new features. Liquid Glass Toggle iOS 26.1 lets you choose your preferred look for Liquid Glass. In the Settings app, under Display...
Liquid Glass General Feature

Apple Shares Liquid Glass Design Gallery

Thursday November 6, 2025 2:45 pm PST by
Apple is promoting the new Liquid Glass design in iOS 26, showing off the ways that third-party developers are embracing the aesthetic in their apps. On its developer website, Apple is featuring a visual gallery that demonstrates how "teams of all sizes" are creating Liquid Glass experiences. The gallery features examples of Liquid Glass in apps for iPhone, iPad, Apple Watch, and Mac. Apple...
airtag purple

Apple's Website Lists AirTag 4-Pack at Shockingly Low Price [Updated]

Friday November 7, 2025 6:40 am PST by
Apple's online store in the U.S. is suddenly offering a pack of four AirTags for just $29, which is the same price as a single AirTag. This is likely a pricing error, and it is unclear if orders will be fulfilled. Apple has not discounted the AirTag four-pack in any other countries that we checked. Delivery estimates are already pushing into late November to early December, suggesting...
apple watch se 3 always on

Apple to Remove iPhone-Apple Watch Wi-Fi Sync in EU With iOS 26.2

Thursday November 6, 2025 4:37 am PST by
Apple in iOS 26.2 will disable automatic Wi-Fi network syncing between iPhone and Apple Watch in the European Union to comply with the bloc's regulations, suggests a new report. Normally, when an iPhone connects to a new Wi-Fi network, it automatically shares the network credentials with the paired Apple Watch. This allows the watch to connect to the same network independently – for...
ikea smart home devices

IKEA Debuts 21 HomeKit-Compatible Smart Bulbs, Sensors, and Controls

Thursday November 6, 2025 4:08 pm PST by
IKEA today announced the upcoming launch of 21 new Matter-compatible smart home products that will be able to interface with HomeKit and the Apple Home app. There are sensors, lights, and control options, all of which will be reasonably priced. Some of the products are new, while some are updates to existing lines that IKEA previously offered. There are a series of new smart bulbs that are...
Home Hub Command Center with Dome Base Feature

Apple's 2026 Smart Home Revamp: All the Rumors

Wednesday November 5, 2025 3:54 pm PST by
It's been over a decade since Apple's HomeKit smart home platform launched, and it is overdue for an update. HomeKit and the Home app can no longer keep up with AI-powered solutions from other companies like Google and Amazon, but that's set to change with a smart home revamp that Apple has planned for 2026. Home Hub Apple is working on a home hub or "command center" that will serve as a...

Top Rated Comments

AngerDanger Avatar
93 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
93 months ago
What a beautiful piece of engineering!
Score: 13 Votes (Like | Disagree)
Christoffee Avatar
93 months ago
Amazing tech. How far we've come from my Spectrum and Amiga days!
Score: 9 Votes (Like | Disagree)
Nozuka Avatar
93 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
93 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
93 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)