April 18, 2024

Smartwatch Battery Showdown: Which Wearable Device Lasts Longest?

If you’re a fan of smartwatches, you know that they have a lot of features, but each new generation of features comes at a cost. While our insatiable desire for our devices to do more shows no slowdown, battery technology is not evolving at the same pace and battery is one of the biggest concerns when choosing a reliable smartwatch.

Unlike a phone, which can be designed a little thicker to accommodate a larger battery but hide it well, a smartwatch should be designed as a watch first and as a technology second. This doesn’t bode well for smartwatch makers, and while devices like the Garmin Venu 3 and Withings Scanwatch 2 achieve multi-day battery life, they offer a more limited feature set than the big three smartwatches from their manufacturer. phones: Apple Watch Ultra. 2, Galaxy Watch 6 Classic and Pixel Watch 2.

So which of these devices offers the best battery life and charging? Does all-day battery life really mean all day? Is the Apple Watch Ultra 2’s battery much better to justify its price of almost double that of the competition? Let’s find out!

Cargo Showdown

How fast do the best watches recharge?

The Google Pixel Watch 2 lying face down on a wooden surface with its charger next to it

The idea of ​​charging a smartwatch every night is inherently wrong. Instead of draining to empty and then filling up, all batteries are designed to perform best between 20% and 80% charged. As a result, five 10-minute charges are better than a single 50-minute charge, and every watchmaker includes some type of “top-up” fast charge.

To find out how good this charge is, I measured the time needed to fully charge it and the impact of a 15-minute charge. Note that the Galaxy Watch 6 Classic comes in two sizes, each of which has a different sized screen and battery. The 43mm Watch 6 Classic has a 300mAh cell; the larger 47mm model comes with 425mAh. My tests were done with the largest model.

Apple Watch Ultra 2

Galaxy Watch 6 Classic (47mm)

Pixel Clock 2





Load to maximum

93 minutes

82 minutes

78 minutes

15 minute charge (%)




Neither of these watches charge completely quickly, although you won’t have any problems if you charge them overnight. On top-up charging, a 15-minute charge should give you a few hours of extra use, but 30 minutes is the ideal charging time to get an extra half-day of use.

Detailed battery tests

All-day battery life is a reality

It’s one thing to recharge when you can, but what happens when your smartwatch’s battery is almost dead and you still need it? What happens if you wake up and forget to charge during the night? Will your smartwatch battery last the second day?

During my testing, my usage was average to poor, including using notifications, alarms, and health features, but not including any workout tracking. Training tracking and active use of the sensors will likely affect battery life, although the actual impact will depend on your specific use. The tests below can be considered best-case scenarios with moderate use of the core features each smartwatch offers.

Chart showing the battery life of the Apple Watch Ultra 2, Pixel Watch 2, and Galaxy Watch 6 on a single charge

For this test, I charged each watch to maximum, wore them all simultaneously (each connected to a different phone with similar apps and complications), and checked the battery percentage at various intervals over two days. This isn’t the most scientific test, thanks to a variety of variables, but it does indicate the endurance and battery patterns of each of these smartwatches.

Chart showing Pixel Watch 2 and Galaxy Watch 6 battery life on a single charge

In this test, the Pixel Watch 2 and the 47mm Galaxy Watch 6 Classic show almost identical resistance and battery usage patterns. Samsung and Google claim all-day battery life, and it’s clear from these tests that both devices generally deliver. However, if you forget to charge overnight, it is highly unlikely that you will make it to the end of the day without needing a recharge charge.

Chart showing Apple Watch Ultra 2 battery life on a single charge

The Apple Watch Ultra 2 is a completely separate discussion. Apple claims up to 36 hours of battery life (or up to 72 hours with power saving mode on), and in my testing, the Apple Watch Ultra 2 easily surpassed this figure.

Average and maximum battery life.

With a much larger battery, the Apple Watch Ultra 2 takes the lead

How accurate is the one-day test I ran above? I ran similar tests over several days to figure this out, using all three watches simultaneously and individually. I tracked the various battery life percentages and paid close attention to the individual battery life characteristics of each smartwatch.

Most of my testing found that all three smartwatches followed the same battery trends detailed in the charts. My more extensive testing also allowed me to determine average battery life, with each smartwatch tested and recorded seven times (including simultaneous and individual use).

Here is the average battery life I achieved with each smartwatch:

Apple Watch Ultra 2

Galaxy Watch 6 Classic (47mm)

Pixel Clock 2





Average battery life

46 hours 22 minutes

35 hours 19 minutes

33 hours 18 minutes

What about maximum battery life? With power saving mode enabled, the Apple Watch Ultra 2 managed 76 hours of battery life, the Pixel Watch 2 managed 47 hours, and the 47mm Galaxy Watch 6 Classic managed 48 hours. Using smartwatches in these modes disables most of their smart features, so I don’t recommend it, but it will help extend battery life to get you through the day.

Does the size of the smart watch matter?

Larger batteries mean longer battery life

While we focus on the Galaxy Watch 6 Classic and Apple Watch Ultra 2 in this comparison, Samsung and Apple offer alternatives that you could also consider. The Apple Watch Series 9 is half the price of the Apple Watch Ultra 2, but has a battery that’s almost half the size (308 mAh vs. 564 mAh). In our brief tests with the Apple Watch Series 9, we found that the battery lasts around 32 hours, ensuring a full day of use even with heavy use.

What about the size of the watch? Here’s how battery sizes compare by model and size:

Galaxy Watch 6

Galaxy Watch 6

Galaxy Watch 6 Classic

Galaxy Watch 6 Classic











As I mentioned above, testing of this piece was conducted using the larger 47mm Galaxy Watch 6 Classic. The smaller 43mm model naturally comes with a smaller battery. You might also consider the Galaxy Watch 6 instead of the Galaxy Watch 6 Classic featured here. Aside from the different case sizes, the 40mm Watch 6 and 43mm 6 Classic have identical specs; The same goes for the larger 44mm Watch 6 and 47mm 6 Classic.

Both smaller versions of the Watch 6 feature the same 300 mAh battery, while the larger ones are standardized at 425 mAh. With this in mind, we’d expect a marked decrease in battery life (and faster overall charging speed) with the smaller clock sizes, but the exact impact remains to be determined. Assuming everything remains the same except the battery capacity, we would expect the smaller batteries to reduce battery life, but the smaller watch face should negate some of the loss.

Every OEM delivers on their promises and more

A refreshing change of pace

Pixel Watch 2 and Galaxy Watch 6 Classic Side on display at

The biggest surprise for me when taking this test? All OEMs deliver on their promise that the battery will last all day, and in fact, each watch lasts longer in normal use. This is the opposite of how each company sells their phones, but it makes logical sense that they would under-promise and over-deliver on their battery life claims. Of course, battery life will almost certainly vary depending on your usage.

What about the Apple Watch Ultra 2? Is the extra weight and battery life worth the extra cost? The answer isn’t really, but with the caveat that it doesn’t matter: the Apple Watch Ultra 2 offers the best battery life of any Apple Watch and is considerably better than the Apple Watch Series 9. If you’re locked into the Apple ecosystem , in the end you will choose one of these two.

If you’re an Android user, the Pixel Watch 2 and Galaxy Watch 6 Classic offer almost identical battery life. If this is your main deciding factor, I’d probably choose the Galaxy Watch 6 because I prefer Samsung’s approach to health. There are two styles to choose from and I think the Galaxy Watch 6 Classic offers better value for money. However, if you choose the Pixel Watch 2, you probably won’t be disappointed with its battery life.

  • Apple Watch 2 Ultra, front view

    Apple Watch Ultra 2

    $749 $799 Save $50

    Apple Watch Ultra 2 offers the largest battery capacity and best battery life of any Apple Watch. If endurance is your top priority, look no further!

  • google pixel watch 2 white background at an angle

    Google Pixel Watch 2

    It has a smaller battery, but it shows that size isn’t everything, as the Pixel Watch 2’s battery packs plenty of power. Lasts as long as the Galaxy Watch 6 Classic!

  • Samsung Galaxy Watch 6 Classic black tilted to the right

    Samsung Galaxy Watch 6 Classic

    The Galaxy Watch 6 Classic offers the best of the Classic line in an updated smartwatch, but also offers endurance and all-day battery life.

Nirave is a creator, evangelist and founder of House of Tech, which focuses on the intersection of health and technology. After suffering a heart attack at the age of 33, she has focused on how we can use data to improve our health and ultimately live a long, more fruitful life. She follows him on Instagram, Threads, and YouTube to get live updates on her sleep and health journeys. She can also be found at HoT.tech.

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