OnePlus Watch 3: A 5-Day Battery That Costs Less Than Your Coffee Habit

A smartwatch that lasts five days on a single charge may sound like a tech fantasy, but OnePlus is selling it to you for $300.

The OnePlus Watch 3 claims to deliver this feat through a combination of silicon-carbon batteries and a dual operating system architecture—Qualcomm’s Wear OS 5 for active tasks and the BES2800 chip for background operations.

With a 1.5-inch AMOLED screen and a 631-mAh battery, the device also promises up to 16 days in power-saving mode, though real-world verification of this claim remains a challenge for casual users.

One reviewer noted, 'It certainly feels like OnePlus is coming into its own as a true competitor to the Pixel Watch.' However, the $300 price tag on Amazon includes compromises.

The ECG feature, a key health tool in many smartwatches, is unavailable in the U.S. and Canada due to regulatory gaps. This regional limitation highlights the tension between hardware innovation and global compliance hurdles.

For non-technical buyers, verifying the 16-day power-saving mode requires disabling most features, which may render the watch impractical for daily use.

The dual OS design aims to balance performance and longevity, but users must weigh this against the $300 cost and missing functionalities in certain regions.

The Watch 3’s availability as a paid product—rather than open-source—further limits transparency about its energy management claims.