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Apr 12, 2001
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Apple's claim that the Apple Watch Series 11 offers 24 hours of battery life has drawn scrutiny as closer examination of Apple's own testing data reveals that the increase from the Series 10's 18-hour rating is largely attributable to changes in testing methodology rather than a major hardware change.

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Apple lists the Apple Watch Series 11 as capable of lasting up to 24 hours on a single charge, a notable increase over the Series 10's 18-hour claim, which had been the company's published standard since the launch of the original Apple Watch in 2015.

As spotted by a user on the MacRumors forums, the primary difference between the two test scenarios in Apple's official documentation is the inclusion of sleep tracking in the Series 11's evaluation. Apple states that the 24-hour figure is based on 300 time checks, 90 notifications, 15 minutes of app use, a 60-minute workout with music playback, and six hours of sleep tracking. The comparable Series 10 test lists the same parameters but does not include sleep tracking.

While Apple does not break down the exact battery drain of each activity, sleep tracking is generally a low-power feature, allowing older Apple Watch models to be worn overnight without fully depleting their charge. Many users have pointed out that Apple Watches have long exceeded the company's stated 18-hour battery life in real-world use, with most users comfortably achieving overnight tracking. This suggests that the six-hour increase is primarily a result of Apple adding sleep tracking to its official scenario, rather than a significant increase in real-world battery life.

Apple also publishes Low Power Mode battery life estimates, which further demonstrate only modest changes. The Series 11 is rated for 38 hours of battery life in Low Power Mode, compared to the Series 10's 36-hour rating. Here, Apple's footnotes indicate that the Series 11 test used lower levels of activity: 530 time checks, 160 notifications, and 26 minutes of app usage, versus 600 time checks, 180 notifications, and 30 minutes of app use for the Series 10. Both tests included a 60-minute workout and six hours of sleep tracking. The reduced activity assumptions make it difficult to directly compare figures, but even Apple's own hourly calculation achieves only an approximate 8% improvement.

The Apple Watch Series 11 does feature slightly larger batteries across its range of case sizes. According to official safety documentation, battery capacities for Series 11 models range from 1.245 to 1.403 watt-hours, depending on case size, compared to 1.118 to 1.266 watt-hours for Series 10 models. This represents a roughly 7% to 10% increase in capacity, far less than the 33% jump implied by Apple's move from an 18-hour to a 24-hour claim.

Article Link: Apple Watch Series 11's Increased 24-Hour Battery Life Has a Catch
 
There are leaked specs showing about an 11 percent larger battery in the Series 11 and about 6 percent in the Ultra 3. The Series 11 is being advertised with 33 percent more battery life which is 6 extra hours. The Ultra 3 is being advertised with 17 percent more battery life which is also about 6 extra hours. Most of these claims are not just from the battery increases but from a change in how Apple calculates battery life. They now assume 6 hours of sleep focus use as part of a normal day.

I was the original poster that Macrumors linked to. I want to be clear that I am not saying Apple is wrong to change their method. In a 24 hour period most people do sleep. The point is that the sudden jump in the numbers, especially the Series 11 claim, is not simply from a big efficiency gain or a huge new battery. To hit the advertised number you need a full 6 hours in sleep mode. It does not represent 6 more hours of awake style use with notifications and the screen on.
 
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Or we can wait until we get real world results from reviewers instead of speculation. Someone here will still be able to say “I told you so” in either scenario.

Apple posts the exact testing methodology on their website and their results so we have a lot to work with. The reality of course is every single Apple Watch user uses their watches differently so some seem to have far better, or far worse, results. What I am confident of is if you take a Series 10 and a Series 11 and leave them doing something ACTIVE... maybe recording a workout with GPS from 100% to 0% you will see the Series 11 win but by a small margin not nearly 6 hours longer. To get the 33% increase in battery life claimed you need to spend a significant amount of time using the watch in sleep focus mode (and of course many people will!) ... none of this is a diss on Apple but more to show how a change in methodology combined with some crafty PR can make things appear different than we initially thought.
 
Apple posts the exact testing methodology on their website and their results so we have a lot to work with. The reality of course is every single Apple Watch user uses their watches differently so some seem to have far better, or far worse, results. What I am confident of is if you take a Series 10 and a Series 11 and leave them doing something ACTIVE... maybe recording a workout with GPS from 100% to 0% you will see the Series 11 win but by a small margin not nearly 6 hours longer. To get the 33% increase in battery life claimed you need to spend a significant amount of time using the watch in sleep focus mode (and of course many people will!) ... none of this is a diss on Apple but more to show how a change in methodology combined with some crafty PR can make things appear different than we initially thought.
Thanks for the thoughtful, detailed response.
 
So there is a physically larger battery?

OK so it doesn't make up the 24 hours but I'll take any increase in battery life. I use sleep tracking so if it drains less during the night then that's a big improvement for me.
In the artcile a 10% increase in battery size is mentioned.

It doesn’t mean it drains less. Just the test process changed.
 
This makes no sense. Check your logic before posting.

The Series 11 is doing more work than the 10 (which gets to slack off with no sleep tracking), yet still manages to go 6 hours longer. If anything, this suggests the 11 is even more improved than stated.
This is the logic:

Series 10 is dead after the 18 hours test;

Series 11, after the 18 hours test, has approximately 5-10% of battery left, which is enough for 6 hours of sleep tracking or, probably, a couple of hours of normal usage.
 
It's not devious or illegal to change battery life measuring methodology as long as they are clear about it, which it appears they were. I mean, in a 24 hour period, it makes total sense to include some sleep time so that's probably why they changed it. Until the Series 11, the Watch probably didn't have enough battery life to include that minimum 6 hour sleep time to make it to 24 hours.
 
This is the logic:

Series 10 is dead after the 18 hours test;

Series 11, after the 18 hours test, has approximately 5-10% of battery left, which is enough for 6 hours of sleep tracking or, probably, a couple of hours of normal usage.

Bingo. I created the original post just to point out that the 6 hour increase is based on sleep, not awake time use... I initially, and I suspect most, saw the specs on the Series 11 and said "wow 33% more battery life" but now we realize there is an asterisk with the claim which depends on sleep being considered. More battery is always good but at least for me it isn't the giant increase I first assumed when I saw the event.
 
Yeah, my series 7 watch still lasts 24 hours with my use. I have it doing sleep tracking and my morning alarm. It gets charged in the morning while I’m getting ready and is good until the following morning.
How? My Series 9 hardly lasts from 8am until 8pm! And I don't use sleep tracking, don't use fitness, don't do anything with it except occasionally glance at a notification! 🤣
 
I've worn my Series 10 for 2 days straight several times without charging it. It lasts way longer than 18 hours with normal usage. Apple's estimates are based on hefty usage. They are very conservative estimates. It can go much longer than that if you're not beating the thing to death.
 
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Apple's claim that the Apple Watch Series 11 offers 24 hours of battery life has drawn scrutiny as closer examination of Apple's own testing data reveals that the increase from the Series 10's 18-hour rating is largely attributable to changes in testing methodology rather than a major hardware change.

As spotted by a user on the MacRumors forums, the primary difference between the two test scenarios in Apple's official documentation is the inclusion of sleep tracking in the Series 11's evaluation. Apple states that the 24-hour figure is based on 300 time checks, 90 notifications, 15 minutes of app use, a 60-minute workout with music playback, and six hours of sleep tracking. The comparable Series 10 test lists the same parameters but does not include sleep tracking.


So the S11 battery lasts longer when you DO include sleep tracking?
 
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