Amazfit Cheetah 2 Ultra Battery Test: 55 Hours on a Real Ride

The Amazfit Cheetah 2 Ultra just posted a 55-hour GPS battery projection during a real 100km Isle of Wight ride, tested alongside the Garmin Forerunner 970, Wahoo Roam 3, Whoop MG, and Polar Verity Sense. That is not a lab estimate or a manufacturer claim. It is a field number from warm, sunny conditions on a full cycling day, and it is hard to dismiss.

Battery Life: Where the Cheetah 2 Ultra Stands Out

The 55-hour projection puts the Cheetah 2 Ultra in a different conversation than most triathlon watches. The Garmin Forerunner 970 is a strong GPS watch, but Garmin's own GPS battery figures sit closer to 30 to 40 hours in full GPS mode depending on the variant. Coros Vertix 2S reaches 140 hours in GPS mode, but that is a much bulkier, more expedition-focused device. For a watch that still fits a triathlete's wrist comfortably, 55 hours is a real number. For Ironman-distance athletes doing back-to-back long training days, that matters more than peak metrics.

The test was conducted with continuous GPS active across the 100km ride. Warm conditions generally favor optical sensors but can slightly increase processor load for cooling management. The projection method extrapolates remaining capacity against drain rate, so it is an estimate, not a confirmed endpoint. Still, the Cheetah 2 Ultra's drain rate during the ride was clearly measured and consistent enough to make that 55-hour figure credible.

Heart Rate and GPS Accuracy in the Field

The Cheetah 2 Ultra uses a wrist-based PPG optical sensor, meaning it reads blood volume changes via light rather than electrical impulses. On a bike, wrist optical sensors face a known challenge: handlebar vibration creates motion artifact. The Polar Verity Sense was on course as a reference, which is an optical armband sensor rather than an ECG chest strap. That means both reference and test device are PPG-based, which is worth flagging. For the cleanest heart rate ground truth on a bike, a chest strap using electrical impulse measurement would have been the gold standard. That said, the Verity Sense is widely regarded as one of the more accurate optical references available, and comparing two PPG sensors at least controls for methodology.

GPS performance across the Isle of Wight route was also tested. GPS accuracy on multi-watch tests like this gets interesting fast. The Forerunner 970 uses Garmin's latest multi-band GPS, which is strong in open terrain. The Cheetah 2 Ultra also supports multi-band GPS, and Amazfit has improved their satellite acquisition and track smoothing since the original Cheetah line. A 100km cycling route with mixed terrain is a decent real-world stress test, more meaningful than a flat track loop.

How It Compares for Triathlon and Endurance Use

For triathletes, the Cheetah 2 Ultra's battery advantage is most relevant in 70.3 and full Ironman contexts, plus the brick training weeks leading up to them. Whoop MG was present on the test as a recovery reference. Whoop does not track GPS workouts directly, so its role here is likely resting heart rate and HRV comparison rather than workout data. That is a fair use of Whoop: it excels at passive recovery tracking via PPG, not at being a sports watch. The Cheetah 2 Ultra attempts to do both, and the battery result suggests it does not sacrifice too much endurance to fit into a daily-wear form factor.

Cyclists using head units like the Wahoo Roam 3 will not replace that with a wrist watch, but for runners and triathletes who want one device for training and racing, the Cheetah 2 Ultra's 55-hour figure means you can run a full Ironman, sleep with the watch tracking recovery via optical SpO2 and HRV, and start the next long ride without charging. That workflow is genuinely useful. We covered the Cheetah 2 Pro's running performance in detail in our [Amazfit Cheetah 2 Pro Review](/en/articles/amazfit-cheetah-2-pro-review-running-tests-vs-garmin-and-polar-2026-05-21), and the Ultra adds battery headroom on top of that baseline.

What Is Missing

The test does not yet give us swim data, which matters for triathletes. Wrist optical HR during swimming is notoriously unreliable due to water movement and pressure, and no watch has fully solved that. We also do not have a confirmed total discharge endpoint, only a projection. The Garmin Forerunner 970 still leads on ecosystem depth: training load metrics, structured workout support, and Connect integration are more mature than Amazfit's Zepp platform for most athletes. Amazfit's sleep and recovery algorithms are improving but not yet at Whoop or Polar Ignite-level depth for cycle-synced or hormonal tracking use cases.

The Cheetah 2 Ultra looks like a strong option for battery-obsessed endurance athletes who want a single wrist device under 500 dollars. It beats the Forerunner 970 on raw battery by a significant margin and undercuts the Coros Vertix 2S on bulk. If Garmin ecosystem lock-in matters to you, the 970 wins on software. If you want maximum GPS endurance in a race-capable watch, the Cheetah 2 Ultra just made a strong case on a real 100km course.