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The Amazfit T-Rex Dual Solar does not have a published universal charge rate, such as a percentage per hour. Amazfit instead gives battery-life estimates: up to 34 days with three hours of front-side sunlight a day, or up to 51 days with three hours of rear-side sunlight a day, at 50,000 lux. Those are manufacturer estimates for typical use—not guaranteed results or independently measured charging rates.
What do Amazfit’s solar-charging figures mean?
Amazfit lists up to 25 days of battery life without solar charging, up to 34 days with daily front-side solar exposure, and up to 51 days with daily rear-side exposure. The two solar-assisted estimates assume three hours of exposure per day at 50,000 lux. All three figures are for typical use.
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| Typical-use scenario | Amazfit’s stated battery life | Published condition |
|---|---|---|
| Without solar | Up to 25 days | No solar condition stated |
| Front-side solar | Up to 34 days | Three hours per day at 50,000 lux |
| Rear-side solar | Up to 51 days | Three hours per day at 50,000 lux |
These are estimates of total battery endurance, not measurements of how much charge the watch gains in a set period. Amazfit does not publish a general percentage-per-hour rate or a formula for converting different light levels and exposure times into extra battery life. Its US product page and specifications list a 660 mAh battery and these runtime scenarios (Amazfit T-Rex Dual Solar product page; technical specifications).
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsHow does the watch collect sunlight?
The T-Rex Dual Solar collects light from two surfaces: the AMOLED display on the front and a glass-ceramic back plate on the rear. Amazfit presents solar charging as a way to supplement the battery when conditions permit. Its published typical-use estimates differ by which side receives the stated daily exposure: up to 34 days for front-side exposure and up to 51 days for rear-side exposure. These are the manufacturer’s estimates, not a controlled, independently measured comparison across users.
#1 Best Overall
- ULTRA-BRIGHT AMOLED DISPLAY: With peak brightness of 2,000 nits, the Amazfit smart watch delivers easy reading of maps and workout data in any light. Night mode and Glove Mode enhance visibility for clear viewing
- DURABILITY FOR EXTREME CONDITIONS: This rugged smart watch, engineered with a 316L stainless steel bezel, withstands temperatures from -22F to 158F, and is water-resistant to 328 feet and can be used for freediving to a depth of 147 Feet
- EXTENDED BATTERY LIFE: The Amazfit T Rex 3 offers over 3 weeks of power with typical use or up to 180 hours in GPS mode, providing long-lasting performance for hiking trips or outdoor activities
- PRECISION NAVIGATION TOOLS: The smart watch for men and women provides free global maps with dual-band positioning. Six satellite systems offer fast, accurate GPS connections and precise turn-by-turn navigation
- EXPANSIVE FITNESS TRACKING: This fitness watch offers 170plus workout modes and AI-generated training plans, providing real-time updates to guide your fitness journey from hiking to surfing
What affects solar charging and battery life?
Light intensity and time in the light
The solar-assisted estimates specify 50,000 lux for three hours per day. Less intense light or shorter exposure does not meet those stated conditions, and Amazfit provides no conversion formula for predicting the resulting runtime.
Which side is exposed
Amazfit publishes separate front- and rear-side scenarios. The surfaces and stated estimates differ, so use the figure that matches the side exposed; neither figure establishes a universal outcome for everyday wear.
Rank #2
- BIGGER DISPLAY. MAX CLARITY: Active Max features a shine brighter screen with a 3,000-nit display engineered for ultimate clarity, even under the harshest sunlight. See your data clearly on a large 1.5″ ultra-bright AMOLED display built for easy readability in any condition — from the gym to the mountains.
- BIGGER BATTERY, MAX ENDURANCE: Go longer between charges with reliable power built for every routine. With up to 25 days of battery, the Active Max smart watch keeps up with your routine day and night.
- BIGGER STORAGE. SMARTER MAPS: With 4GB of onboard storage, you have more space for your favorite music and downloaded maps with turn-by-turn directions — all accessible right from your wrist.
- BIGGER TRAINING, SMARTER INSIGHTS: From strength sessions to long runs, the Active Max tracker adapts to how you train with 170+ workout modes and personalized Zepp Coach running plans.
- BIOCHARGE ENERGY MONITORING: Your BioCharge score adjusts based on your daily workouts and stress levels to help you understand when to push harder and when to rest, so you can train smarter and recover better.
Settings and operating mode
Battery life varies with settings and operating conditions. Amazfit also publishes different assumptions for typical, heavy, GPS, clock, and extreme modes. The typical-use solar figures should not be treated as estimates for those other modes.
Temperature and battery state
Solar charging is subject to temperature restrictions. Amazfit says charging stops if the temperature threshold is exceeded to protect the watch. It also says solar charging is disabled when the battery is nearly full.
Rank #3
- STYLISH DESIGN, VIBRANT DISPLAY: The lightweight aluminum build blends effortless style with workout durability, while the vivid 1.97" AMOLED display keeps your data easy to read, even under bright sunlight.
- ALL-IN-ONE ACTIVITY TRACKING: The Amazfit Bip 6 fitness tracker watch offers 140+ workout modes including HYROX Race and Strength Training, plus personalized AI coaching and 50m water resistance.
- UP TO 14 DAYS BATTERY LIFE: The Amazfit Bip 6 smart watch powers through your training and recovery for up to two weeks at a time - no nightly charging needed.
- ACCURATE GPS TRACKING & NAVIGATION: Stay on course with free downloadable maps and turn-by-turn directions. Support from 5 satellite systems ensures precise tracking of every move and fast GPS connection.
- 24/7 HEALTH MONITORING: The Amazfit Bip 6 smartwatch provides precise, real-time monitoring of heart rate, sleep, blood-oxygen and stress, empowering you with actionable insights to optimize your health and fitness.
Can solar charging replace cable charging?
No. Amazfit says solar charging helps slow power consumption and extend battery life, but it cannot replace standard USB cable charging. Treat sunlight as supplemental energy rather than a substitute for charging the watch by cable.
How certain are the published runtime estimates?
The 25-, 34-, and 51-day figures are Amazfit’s product claims, published in 2026 for the US product materials. They establish the manufacturer’s stated conditions and estimates; they do not independently verify real-world charging performance. Your result can vary with exposure, settings, operating conditions, temperature, and battery state.
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