Apple Watch Ultra battery specs revealed - and it's much bigger than the Series 8

Certification database leak uncovers the details Apple typically keeps secret
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The Apple Watch Ultra features a 76% bigger battery than the Watch Series 8.

That's if a leak from a Chinese certification database (first reported by MySmartPrice) is to be believed, indicating that the first generation of Apple's outdoor-focused smartwatch will feature a 542mAh unit.

Apple doesn't ever officially release battery specs concerning its smartwatches, but the database reveal suggests that this represents a big jump from the Series 8, which sits at 308mAh for the 45mm version. For the 41mm version, that dips to 282mAh.

Of course, what Apple does always reveal is the hours you can expect from its smartwatch, which is why these battery specs aren't necessarily a huge surprise.

Given that the Apple Watch Ultra is quoted at 36 hours - double the usual 'all-day', 18-hour life of the company's standard smartwatches - the jump does appear to match up.

Interestingly, to gain what should end up being roughly 100% more battery life from less than double the overall battery size also suggests the Ultra's battery is also more efficient.

And that efficiency is something that will be boosted even further by the introduction of Low Power Mode in watchOS 9 - a feature that Apple says will take the Ultra's battery life to 60 hours.

As we've hinted, though, while specs are one thing, how this all shakes out in real-world use is another.

We're currently putting the Apple Watch Ultra through our testing process, and we'll have our full verdict - including a comprehensive battery comparison - over the coming weeks.


How we test

Conor Allison


Conor moved to Wareable Media Group in 2017, initially covering all the latest developments in smartwatches, fitness trackers, and VR. He made a name for himself writing about trying out translation earbuds on a first date and cycling with a wearable airbag, as well as covering the industry’s latest releases.

Following a stint as Reviews Editor at Pocket-lint, Conor returned to Wareable Media Group in 2022 as Editor-at-Large. Conor has become a wearables expert, and helps people get more from their wearable tech, via Wareable's considerable how-to-based guides. 

He has also contributed to British GQ, Wired, Metro, The Independent, and The Mirror. 

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