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OnePlus Watch 3 Review: The Best Battery Life of Any Android Smartwatch

This $350 smartwatch can outlast its competitors in battery life and fitness features, but may fall short on software updates.

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Headshot of Vanessa Hand Orellana
Vanessa Hand Orellana Lead Writer
Vanessa is a lead writer at CNET, reviewing and writing about the latest smartwatches and fitness trackers. She joined the brand first as an on-camera reporter for CNET’s Spanish-language site, then moved on to the English side to host and produce some of CNET’s videos and YouTube series. When she’s not testing out smartwatches or dropping phones, you can catch her on a hike or trail run with her family.
Expertise Consumer Technology, Smart Home, Family, Apps, Wearables
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Editor’s note, June 16, 2025: OnePlus released a smaller 43mm version of the OnePlus Watch 3 in silver stainless steel. This review has been updated to reflect the new addition to the lineup. 

Editor’s note, March 4, 2025: We’ve updated our score for the OnePlus Watch 3 from 8.5 to 8.8 to reflect that OnePlus extended its Wear OS update cycle to three years of software and security updates, with support lasting until 2027 with Wear OS 7.


In my 10-plus years of testing smartwatches, I’ve never had to actively try to drain a battery. That changed when I strapped on the $350 OnePlus Watch 3. Five days into my battery test, after charging it to 100%, this watch was still going strong — tracking my sleep, runs and vitals without missing a beat.

I’ll admit, the Watch 3 didn’t make the best first impression — its masculine design and oversized 47mm screen practically swallowed my average-size wrist. I half-expected to write it off as another midrange smartwatch destined to collect dust in a drawer. But the exceptional battery life makes it easy to overlook a few drawbacks, like the size and the lack of ECG functionality in the US.

8.7/ 10
SCORE

OnePlus Watch 3

Pros

  • 5-day battery life with all features enabled
  • Sleek comfortable design
  • Customizable buttons as shortcuts Advanced metrics for select sports modes

Cons

  • Only three years of software and security updates
  • Lacks menstrual cycle tracking
  • ECG is not available in the US or Canada
  • No LTE version or iOS compatibility

Four years after its shaky debut, it’s clear the company has paid close attention to its fanbase. OnePlus’ underdog smartwatch has matured into a true competitor to Samsung and Pixel watches. It delivers the best battery life I’ve ever tested on a Wear OS device, while packing solid health features into a subdued, elegant design — now available in a smaller size, too.

Battery life takes center stage

Unlike the original $160 OnePlus Watch and last year’s $180 Watch 2R, whose main draw was affordability, the Watch 3 shifts the focus from price to performance. With its $350 price tag, OnePlus is positioning it as a premium flagship device, competing directly with similarly priced Wear OS watches like the Google Pixel Watch 3 and Samsung Galaxy Watch 7. What truly sets it apart is its battery, which is larger than its predecessor at 631mAh (versus 500mAh on the Watch 2).

The Watch 3 uses a dual chipset system to split up tasks and optimize power consumption and get even more out of its big battery. The Snapdragon W5 processor focuses on powering app usage, while the BES2800 MCU Efficiency chip handles background tasks that don’t use as much power. 

Though initially skeptical, my two weeks of testing confirmed that the OnePlus Watch 3 delivers on its five-day battery claim. I did three GPS workouts, one of which was an hour and a half hike, and six full nights of sleep tracking. Even its fiercest Wear OS competitors would struggle to last three days without resorting to using a low-power mode that strips the watch of its «smart» features and turns it into a glorified digital clock. The only caveat with the Watch 3 is that it remains on the default «Smart mode» to achieve the full five days. This mode has a raise-to-wake screen and requires using one of OnePlus’ official watch faces. I typically prefer an always-on display with a busier watch face filled with my most-used complications and shortcuts which would likely bring the battery life closer to three days — still a feat considering how bright the screen is, even in dormant mode.

When I first started testing the watch, I made the mistake of opting for a non-OnePlus watch face with a three out of three rating on the battery drain scale and still managed to squeeze in four days worth of charge. While I haven’t tested the claim yet, OnePlus says the watch can make it to 16 days in «Power Save» leaving it mostly as a dedicated fitness tracker rather than a full-featured smartwatch. 

Of course, everyone has a different version of what «normal» use is, and when you finally charge it, the Watch 3 goes from zero to 100% in just under an hour. 

Polished design, now in two sizes

The OnePlus Watch 3 has a sleek stainless steel design and a rotating crown with a textured grip that makes it easy to turn. A slim titanium bezel frames the screen, reminiscent of the old rotating bezels on early Samsung watches I loved. Sadly, this one doesn’t move, but I like how it elevates the design, making it look less like a giant circular 1.5-inch AMOLED display strapped to my wrist. 

This is a good-looking watch. But as a woman with an average-size wrist, this watch feels huge and clearly not designed with me in mind. I don’t need a rose gold frame and sparkly pink band — I just wish it offered more inclusive sizing options and maybe a classic gold version.

Less than three months after I first tested the watch, OnePlus responded to feedback about sizing and released a smaller 43mm version (in silver steel) in June 2025, with the same great features as the original 47mm model.

The larger 47mm watch comes in a black or silver stainless steel finish, with interchangeable rubber bands in moss green, black, Nordic blue or a new white color released alongside the smaller model. The addition of the smaller size makes the watch more appealing to women, but it’s still missing one key feature I’ve come to expect on a smartwatch: menstrual tracking.

Robust health features, minus period tracking

It’s a big miss that OnePlus didn’t include menstrual tracking on the Watch 3. Menstrual tracking is now a standard feature in newer Apple Watch and Garmin smartwatches. The Watch 3 has pretty much every other health feature including temperature tracking, which can be used to help identify a woman’s ovulation window.  

Oversight aside, it’s clear that OnePlus is investing heavily in health tracking. Beyond basic heart rate and sleep data, the watch measures more advanced metrics like cardiovascular health, blood oxygen levels, wrist temperature, and overall well-being, including emotional and stress levels. It also features an electrocardiogram, though as of publication, OnePlus hasn’t sought FDA approval, meaning the feature will not be active in the US or Canada.

While not medical-grade, OnePlus says that the Watch 3’s health metrics are more accurate than in previous models, thanks to upgraded sensors, refined algorithms, and improved cover glass over the back sensors for clearer readings.

The Watch 3 also debuts a 60-second health check-in, a feature that checks all your vitals at once by pressing your finger on the watch’s bottom button to create a circuit. My first health check-in was concerning and displayed a red exclamation mark with the word «abnormal» next to it. It turns out that all my vitals were in range, but my sleep score was so low that it skewed the results. 

Battery life is a game changer for sleep tracking 

As a low-key sleep-tracking hater, I never realized just how much battery life factored into my frustration. As a parent of young kids, I already know I’m not getting enough sleep, and seeing a bad sleep report first thing in the morning just sets me up for a day of dragging and self-pity. I feel the same way about wellness checks. Not having to take off the watch for five consecutive days made me more inclined to track my sleep, and I may have even learned a thing or two about my sleep patterns. 

The Watch 3’s long battery let me collapse into bed at the end of the day without worrying whether my watch had enough charge to last through the night. The watch even tracked my sleep on night six, despite being down to 10% battery in «Power Save» mode. The watch also has an option to monitor SpO2 (blood oxygen levels) and breathing patterns during sleep to help identify more serious breathing issues, but it will drain the battery faster and needs to be activated manually from either the watch or the mobile app.

According to a recent interview from Wareable, OnePlus is already in the process of seeking FDA approval for sleep apnea detection, which may make the extra battery drain worthwhile.

A worthy fitness companion to put you through the paces 

In terms of fitness, the OnePlus Watch 3 covers all the basics, with more than 100 different sports modes, six of which it detects automatically: running, walking, rowing, elliptical machine, cycling and swimming. It also offers a «professional» mode for 11 sports that keep tabs on more nuanced metrics related to that sport. For runners, it’s things like form and foot balance, and for tennis players, it’s swing speed and stroke. While it may be overkill for most, as a runner who recently learned how to leverage heart rate zones to intensify workouts, I was excited to nerd out on the additional metrics. 

I used it during my usual 3-mile run and learned that while I have excellent balance between my right and left feet, my ground contact time (how long my foot stays on the ground) and vertical oscillation (how much I bounce) could use some improvement to make my runs more efficient and less injury-prone. The app provides context for the additional data, but it be overwhelming, and you have to dig around for a definition of each metric. I was also left longing for more actionable tips for improving my stats.

The One Plus Watch 3’s heart rate tracking kept up with my Polar chest strap (the gold standard for athletes), with a lag of just a second or two and a one point difference in average heart rate between the chest strap and the watch. Heart rate serves as a baseline for many of the fitness metrics on the Watch 3. However, once I started running uphill and inching closer to my maximum heart rate, I noticed that lag time increased to about 25 seconds between what the chest strap was showing (on my phone) and the number on my wrist. I tried tightening the band, but it only helped temporarily. By the end of my workout, the watch showed that I had stayed in my peak heart rate zone for 19 seconds, while the chest strap recorded me in this zone for about three and a half minutes.

The lag could be partially due to the sensor’s proximity to the heart (versus the wrist). Sweat and arm movement could also interfere with an accurate read — a problem for most smartwatches. Whatever the case, heart rate accuracy could be an issue if you use it for high-intensity sports or more serious training. You’re still better off using a chest strap.

Another key feature for outdoor sports enthusiasts is its dual-frequency GPS tracking system, which OnePlus says can position you accurately even in challenging environments, such as crowded cities surrounded by high rises. I live in a rural environment that’s more sheep than skyscrapers, so I haven’t been able to fully test this claim. It did position me perfectly on my hour and a half hike through oak trees and vineyards.

With an IP69 rating, the OnePlus Watch 3 is also water-resistant up to 50 meters.

Weighed down by Wear OS and limited updates

The Watch 3 runs on Wear OS 5, with a few additional OnePlus design and navigation features. You can customize the rotating crown and side button as shortcuts, but everything else will feel like a standard Wear OS watch packed with your downloaded apps. 

The interface of the Watch 3 feels sluggish, with a slight lag in response time, though it became easier to use as I got more familiar with the swipe and tap directions. The UI isn’t exactly intuitive, either. For example, the battery icon shows the remaining charge but doesn’t let you switch to «Smart» or «Power Save» mode, which, after some trial and error, I found hidden behind what looks like an infinity icon. There are also three ways to access the workout screen, but only one of those ways will allow you to add a workout type (through the list of apps). This may be more of a Wear OS navigation issue than a OnePlus problem, but it’s still cumbersome.

Additionally, you’ll need to download the separate OHealth app to your phone to access the watch’s full range of health-tracking features. The app itself is visually appealing and intuitive, but the setup wasn’t seamless. It took multiple tries to sync with my Google Health data. It’s worth noting that I was using a developer’s version of the OHealth app, so setup may be smoother on the public version.

The OnePlus Watch 3 may also become obsolete faster than some of its rivals. Unlike Samsung’s Galaxy Watches, which offer five years of Wear OS updates, the OnePlus guarantees support for software and security updates only until 2027. The Watch 3 will get updated to Wear OS 6, and 7, putting it in line with the Pixel 3, which launched in the fall of 2024.

Solid battery life and features tip the scale

If battery life is at the top of your wishlist, this is one Android smartwatch that’s definitely worth considering. The OnePlus Watch 3 is a premium smartwatch at a midrange price that checks nearly all the boxes for health and fitness features and outlasts most competitors when it comes to battery life — just not when it comes to software updates. The OnePlus Watch 3 is now available for $350 on the OnePlus website.

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The Sun’s Temper Tantrums: What You Should Know About Solar Storms

Solar storms are associated with the lovely aurora borealis, but they can have negative impacts, too.

Last month, Earth was treated to a massive aurora borealis that reached as far south as Texas. The event was attributed to a solar storm that lasted nearly a full day and will likely contend for the strongest of 2026. Such solar storms are usually fun for people on Earth, as we are protected from solar radiation by our planet’s atmosphere, so we can just enjoy the gorgeous greens and pretty purples in the night sky.

But solar storms are a lot more than just the aurora borealis we see, and sometimes they can cause real damage. There are several examples of this in recorded history, with the earliest being the Carrington Event, a solar storm that took place on Sept. 1, 1859. It remains the strongest solar storm ever recorded, where the world’s telegraph machines became overloaded with energy from it, causing them to shock their operators, send ghost messages and even catch on fire. 

Things have changed a lot since the mid-1800s, and while today’s technology is a lot more resistant to solar radiation than it once was, a solar storm of that magnitude could still cause a lot of damage. 

What is a solar storm?

A solar storm is a catchall term that describes any disturbance in the sun that involves the violent ejection of solar material into space. This can come in the form of coronal mass ejections, where clouds of plasma are ejected from the sun, or solar flares, which are concentrated bursts of electromagnetic radiation (aka light). 

A sizable percentage of solar storms don’t hit Earth, and the sun is always belching material into space, so minor solar storms are quite common. The only ones humans tend to talk about are the bigger ones that do hit the Earth. When this happens, it causes geomagnetic storms, where solar material interacts with the Earth’s magnetic fields, and the excitations can cause issues in everything from the power grid to satellite functionality. It’s not unusual to hear «solar storm» and «geomagnetic storm» used interchangeably, since solar storms cause geomagnetic storms. 

Solar storms ebb and flow on an 11-year cycle known as the solar cycle. NASA scientists announced that the sun was at the peak of its most recent 11-year cycle in 2024, and, as such, solar storms have been more frequent. The sun will metaphorically chill out over time, and fewer solar storms will happen until the cycle repeats. 

This cycle has been stable for hundreds of millions of years and was first observed in the 18th century by astronomer Christian Horrebow.

How strong can a solar storm get?

The Carrington Event is a standout example of just how strong a solar storm can be, and such events are exceedingly rare. A rating system didn’t exist back then, but it would have certainly maxed out on every chart that science has today. 

We currently gauge solar storm strength on four different scales. 

The first rating that a solar storm gets is for the material belched out of the sun. Solar flares are graded using the Solar Flare Classification System, a logarithmic intensity scale that starts with B-class at the lowest end, and then increases to C, M and finally X-class at the strongest. According to NASA, the scale goes up indefinitely and tends to get finicky at higher levels. The strongest solar flare measured was in 2003, and it overloaded the sensors at X17 and was eventually estimated to be an X45-class flare. 

CMEs don’t have a named measuring system, but are monitored by satellites and measured based on the impact they have on the Earth’s geomagnetic field. 

Once the material hits Earth, NOAA uses three other scales to determine how strong the storm was and which systems it may impact. They include: 

  • Geomagnetic storm (G1-G5): This scale measures how much of an impact the solar material is having on Earth’s geomagnetic field. Stronger storms can impact the power grid, electronics and voltage systems. 
  • Solar radiation storm (S1-S5): This measures the amount of solar radiation present, with stronger storms increasing exposure to astronauts in space and to people in high-flying aircraft. It also describes the storm’s impact on satellite functionality and radio communications. 
  • Radio blackouts (R1-R5): Less commonly used but still very important. A higher R-rating means a greater impact on GPS satellites and high-frequency radios, with the worst case being communication and navigation blackouts. 

Solar storms also cause auroras by exciting the molecules in Earth’s atmosphere, which then light up as they «calm down,» per NASA. The strength and reach of the aurora generally correlate with the strength of the storm. G1 storms rarely cause an aurora to reach further south than Canada, while a G5 storm may be visible as far south as Texas and Florida. The next time you see a forecast calling for a big aurora, you can assume a big solar storm is on the way. 

How dangerous is a solar storm?

The overwhelming majority of solar storms are harmless. Science has protections against the effects of solar storms that it did not have back when telegraphs were catching on fire, and most solar storms are small and don’t pose any threat to people on the surface since the Earth’s magnetic field protects us from the worst of it.

That isn’t to say that they pose no threats. Humans may be exposed to ionizing radiation (the bad kind of radiation) if flying at high altitudes, which includes astronauts in space. NOAA says that this can happen with an S2 or higher storm, although location is really important here. Flights that go over the polar caps during solar storms are far more susceptible than your standard trip from Chicago to Houston, and airliners have a whole host of rules to monitor space weather, reroute flights and monitor long-term radiation exposure for flight crews to minimize potential cancer risks.

Larger solar storms can knock quite a few systems out of whack. NASA says that powerful storms can impact satellites, cause radio blackouts, shut down communications, disrupt GPS and cause damaging power fluctuations in the power grid. That means everything from high-frequency radio to cellphone reception could be affected, depending on the severity.

A good example of this is the Halloween solar storms of 2003. A series of powerful solar flares hit Earth on Oct. 28-31, causing a solar storm so massive that loads of things went wrong. Most notably, airplane pilots had to change course and lower their altitudes due to the radiation wreaking havoc on their instruments, and roughly half of the world’s satellites were entirely lost for a few days.

A paper titled Flying Through Uncertainty was published about the Halloween storms and the troubles they caused. Researchers note that 59% of all satellites orbiting Earth at the time suffered some sort of malfunction, like random thrusters going offline and some shutting down entirely. Over half of the Earth’s satellites were lost for days, requiring around-the-clock work from NASA and other space agencies to get everything back online and located.

Earth hasn’t experienced a solar storm on the level of the Carrington Event since it occurred in 1859, so the maximum damage it could cause in modern times is unknown. The European Space Agency has run simulations, and spoiler alert, the results weren’t promising. A solar storm of that caliber has a high chance of causing damage to almost every satellite in orbit, which would cause a lot of problems here on Earth as well. There were also significant risks of electrical blackouts and damage. It would make one heck of an aurora, but you might have to wait to post it on social media until things came back online.

Do we have anything to worry about?

We’ve mentioned two massive solar storms with the Halloween storms and the Carrington Event. Such large storms tend to occur very infrequently. In fact, those two storms took place nearly 150 years apart. Those aren’t the strongest storms yet, though. The very worst that Earth has ever seen were what are known as Miyake events.

Miyake events are times throughout history when massive solar storms were thought to have occurred. These are measured by massive spikes in carbon-14 that were preserved in tree rings. Miyake events are few and far between, but science believes at least 15 such events have occurred over the past 15,000 years. That includes one in 12350 BCE, which may have been twice as large as any other known Miyake event. 

They currently hold the title of the largest solar storms that we know of, and are thought to be caused by superflares and extreme solar events. If one of these happened today, especially one as large as the one in 12350 BCE, it would likely cause widespread, catastrophic damage and potentially threaten human life

Those only appear to happen about once every several hundred to a couple thousand years, so it’s exceedingly unlikely that one is coming anytime soon. But solar storms on the level of the Halloween storms and the Carrington Event have happened in modern history, and humans have managed to survive them, so for the time being, there isn’t too much to worry about. 

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TMR vs. Hall Effect Controllers: Battle of the Magnetic Sensing Tech

The magic of magnets tucked into your joysticks can put an end to drift. But which technology is superior?

Competitive gamers look for every advantage they can get, and that drive has spawned some of the zaniest gaming peripherals under the sun. There are plenty of hardware components that actually offer meaningful edges when implemented properly. Hall effect and TMR (tunnel magnetoresistance or tunneling magnetoresistance) sensors are two such technologies. Hall effect sensors have found their way into a wide variety of devices, including keyboards and gaming controllers, including some of our favorites like the GameSir Super Nova. 

More recently, TMR sensors have started to appear in these devices as well. Is it a better technology for gaming? With multiple options vying for your lunch money, it’s worth understanding the differences to decide which is more worthy of living inside your next game controller or keyboard. 

How Hall effect joysticks work

We’ve previously broken down the difference between Hall effect tech and traditional potentiometers in controller joysticks, but here’s a quick rundown on how Hall effect sensors work. A Hall effect joystick moves a magnet over a sensor circuit, and the magnetic field affects the circuit’s voltage. The sensor in the circuit measures these voltage shifts and maps them to controller inputs. Element14 has a lovely visual explanation of this effect here.

The advantage this tech has over potentiometer-based joysticks used in controllers for decades is that the magnet and sensor don’t need to make physical contact. There’s no rubbing action to slowly wear away and degrade the sensor. So, in theory, Hall effect joysticks should remain accurate for the long haul. 

How TMR joysticks work

While TMR works differently, it’s a similar concept to Hall effect devices. When you move a TMR joystick, it moves a magnet in the vicinity of the sensor. So far, it’s the same, right? Except with TMR, this shifting magnetic field changes the resistance in the sensor instead of the voltage

There’s a useful demonstration of a sensor in action here. Just like Hall effect joysticks, TMR joysticks don’t rely on physical contact to register inputs and therefore won’t suffer the wear and drift that affects potentiometer-based joysticks. 

Which is better, Hall effect or TMR?

There’s no hard and fast answer to which technology is better. After all, the actual implementation of the technology and the hardware it’s built into can be just as important, if not more so. Both technologies can provide accurate sensing, and neither requires physical contact with the sensing chip, so both can be used for precise controls that won’t encounter stick drift. That said, there are some potential advantages to TMR. 

According to Coto Technology, who, in fairness, make TMR sensors, they can be more sensitive, allowing for either greater precision or the use of smaller magnets. Since the Hall effect is subtler, it relies on amplification and ultimately requires extra power. While power requirements vary from sensor to sensor, GameSir claims its TMR joysticks use about one-tenth the power of mainstream Hall effect joysticks. Cherry is another brand highlighting the lower power consumption of TMR sensors, albeit in the brand’s keyboard switches.

The greater precision is an opportunity for TMR joysticks to come out ahead, but that will depend more on the controller itself than the technology. Strange response curves, a big dead zone (which shouldn’t be needed), or low polling rates could prevent a perfectly good TMR sensor from beating a comparable Hall effect sensor in a better optimized controller. 

The power savings will likely be the advantage most of us really feel. While it won’t matter for wired controllers, power savings can go a long way for wireless ones. Take the Razer Wolverine V3 Pro, for instance, a Hall effect controller offering 20 hours of battery life from a 4.5-watt-hour battery with support for a 1,000Hz polling rate on a wireless connection. Razer also offers the Wolverine V3 Pro 8K PC, a near-identical controller with the same battery offering TMR sensors. They claim the TMR version can go for 36 hours on a charge, though that’s presumably before cranking it up to an 8,000Hz polling rate — something Razer possibly left off the Hall effect model because of power usage. 

The disadvantage of the TMR sensor would be its cost, but it appears that it’s negligible when factored into the entire price of a controller. Both versions of the aforementioned Razer controller are $199. Both 8BitDo and GameSir have managed to stick them into reasonably priced controllers like the 8BitDo Ultimate 2, GameSir G7 Pro and GameSir Cyclone 2.

So which wins?

It seems TMR joysticks have all the advantages of Hall effect joysticks and then some, bringing better power efficiency that can help in wireless applications. The one big downside might be price, but from what we’ve seen right now, that doesn’t seem to be much of an issue. You can even find both technologies in controllers that cost less than some potentiometer models, like the Xbox Elite Series 2 controller. 

Caveats to consider

For all the hype, neither Hall effect nor TMR joysticks are perfect. One of their key selling points is that they won’t experience stick drift, but there are still elements of the joystick that can wear down. The ring around the joystick can lose its smoothness. The stick material can wear down (ever tried to use a controller with the rubber worn off its joystick? It’s not pleasant). The linkages that hold the joystick upright and the springs that keep it stiff can loosen, degrade and fill with dust. All of these can impact the continued use of the joystick, even if the Hall effect or TMR sensor itself is in perfect operating order. 

So you might not get stick drift from a bad sensor, but you could get stick drift from a stick that simply doesn’t return to its original resting position. That’s when having a controller that’s serviceable or has swappable parts, like the PDP Victrix Pro BFG, could matter just as much as having one with Hall effect or TMR joysticks.  

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