How to Get the Most from Your Smartwatch Battery

How many times have you started your training session, pressed the start button, and gone a few seconds, just to see the dreaded: “Battery Low. Enable battery saver?” For me, it’s definitely in the double digits (and the last one was actually this week).

That’s partly why I bought a triathlon smartwatch with solar charging features, which advertises that it enhances the smartwatch’s battery life while I exercise. But is that claim even true? And what, actually, makes a smartwatch battery last longer than its competitors?

Looking for a new smartwatch? Be sure to scroll to the end of this story for our smartwatch battery life comparison chart, and check out our roundup of the best triathlon smartwatches.

Smartwatch battery life factors

Many factors contribute to how often you must charge your smartwatch and how long it’ll actually last in the real world. And if it feels like you can’t find a predictable charging cadence, it might be due to changes in your use and settings (or you just might have the wrong watch for the activities and settings you actually use on a daily basis).

Display types

“Display type will most impact battery life, where MIP (memory-in-pixel) displays consume much less power than AMOLED displays,” says independent content creator and sports technology reviewer Des Yap (aka DesFit).

Memory-in-pixel displays feature technology in which each pixel has its own built-in memory, allowing it to retain image data without the need for constant refreshing. This results in significant power savings, making it ideal for battery-powered devices such as smartwatches and e-readers.

AMOLED, one of the hottest display types right now, stands for Active Matrix Organic Light Emitting Diode. AMOLED is display technology that uses organic compounds to emit light when an electric current is applied. Each pixel in an AMOLED display generates its own light, resulting in features such as deeper blacks, improved contrast, and more vivid/responsive colors compared to older display technologies. However, they consequently require more power to operate.

“Watches like MIP Garmins and most Coros watches tend to have longer battery life than watches like an Apple Watch or Samsung watch,” Yap points out.

Operating systems and health sensors

The operating system used by the smartwatches themselves, which must support and optimize the screen’s capabilities, is also linked to the screen type.

“Smartwatches like Apple Watches and Samsungs tend to perform more daily functions, very much like a smartphone, whereas watches that are more sports and fitness focused don’t as much,” he says.

And given the rise in popularity of health sensors and daily tracking – such as constant GPS and heart-rate monitoring (measured constantly by nearly all watches), but also step counting, sleep and fall detection, and motion tracking for swimming strokes – this can also impact battery life. Hence, watches that take measurements constantly throughout the day will drain your battery more, while those that only take measurements periodically will allow for greater battery life.

Other health sensors can also significantly impact battery life, such as blood oxygen saturation sensors, along with music playback features that use a Bluetooth connection to headphones.

Finally, cellular connectivity (the watch’s ability to connect to a mobile network) and LTE (Long-Term Evolution) – a type of 4G network and standard for high-speed wireless communication for mobile devices that enables voice calls, texts, streaming music, receiving notifications, and using GPS and maps – also significantly impact the battery life of watches.

“Watches with LTE connectivity will drain faster if using their cellular connection versus being paired with a phone,” Yap explains.

Individual use, GPS, and navigation

The way you use your smartwatch – specifically, the number of activities you record daily, their duration, and the features you enable on the watch – remains one of the most crucial factors affecting your device’s battery life.

“For daily battery life, [smartphone] notifications and how much they interact with the watch can make a big impact on how long it can last, along with other settings like display brightness. During activities, GNSS settings (or more commonly referred to as GPS) can have a big impact. Most mid-to-high-end watches have multi-band satellite capabilities where they can not only access different satellite systems but also multiple frequencies at one time,” he explains.

Using the multi-band satellite feature results in higher accuracy but also requires more power. At the same time, most watches remain very accurate if you only use the single-band modes and would only require a multi-band mode in more challenging environments, such as around tall buildings, heavy tree cover, or tall canyon walls where objects can interfere with satellite signals.

Additionally, using the course mode for navigation during an activity also demands substantially more power as the watch processes additional information.

Multisport mode

And what about the multisport mode we use during triathlons, or brick workouts, that we’re so eager to work properly?

“In essence, a triathlon mode tracks multiple, individual activities back-to-back, so there’s no meaningful difference other than triathlon generally lasting longer than most individual activities,” Yap reassures. “However, using an external heart rate strap may extend battery life with some watches, as the connection to an external sensor may consume less power than using the watch’s built-in optical heart rate sensor.”

Solar features and temperatures

Outside temperature generally doesn’t make a significant impact on battery life, as the watch is usually in contact with the skin, however, using the watch in extremely cold temperatures could result in shorter run times.

Now, to the question I had long waited to ask about the solar feature: Does it really help extend the battery power of a smartwatch?

“Watches with monochrome, MIP displays get the most benefit, as the current solar capabilities can increase battery life with enough solar exposure,” Yap says. “These would include Garmin’s [non-AMOLED] Instinct lineup. Watches with full-color MIP displays like those found on on Garmin’s Fenix and Enduro series don’t benefit as much, as the power needs of the display and other functions of the watch are more than what the solar panels can harness, so solar charging with these kinds of watches can delay discharge but not re-charge the watch.”

In other words: A solar-charging capability will only slow down the rate of battery drain, oftentimes imperceptibly based on how much sun the watch is actually exposed to. Very few watches in even the most conservative, “battery-light” settings will actually move the battery charge in a positive direction.

Best smartwatches for triathlon

Based on his multi-year tests and reviews, Des observed that the longest-lasting watches that can track triathlon activities and races were Garmin with their MIP Instinct 1 and 2 series, Garmin’s Enduro and Fenix series, and most Coros devices.

Yet, he also points out that battery life has increased across the board, especially with watches using AMOLED displays. Many watches from numerous brands now have enough battery capacity to last through an Ironman – which could be a deal breaker for long-course triathletes who obviously want to track their data from start to finish.

“There may be other features that someone may be looking for outside of battery life, such as health features, training feedback, as well as the brand’s underlying ecosystem that may be more important.”

Smartwatch battery life

Garmin smartwatch battery comparison

* Does not have triathlon/multisport mode

Suunto smartwatch battery comparison

Polar smartwatch battery comparison

Coros smartwatch battery comparison

Bottom line and recommendations for enhancing battery life

The battery life of your smartwatch mainly depends on its display type, the processor it uses, the number of health sensors, and notifications you use throughout the day – as well as GPS and navigation features. However, here are a few additional pro tips to ensure that when you hit that start button, the watch will last at least until the end of your activity.

1. Regularly charge the watch
2. Reduce the screen brightness
3. Use a single-band GNSS mode when appropriate
4. Avoid music playback during activities
5. Turn off LTE connectivity whenever possible
6. Steer clear of course navigation
7. Use an external heart rate sensor