Amazfit T-Rex Dual Solar brings AMOLED plus two panels

Estimated reading time: 6 minutes · Last updated: 23 September 2026

Amazfit’s T‑Rex Dual Solar pairs an AMOLED screen with two separate solar panels — one on the front ring and a second on the caseback — in an attempt to reclaim battery life for a smaller battery-equipped smartwatch. The watch ships with a 660mAh battery, a 1.3″ AMOLED display and a $649 / 649EUR price, and it borrows most of its feature set from the T‑Rex Ultra 2. Ray Maker’s hands-on testing, as first reported by DC Rainmaker, measured measurable but limited solar returns: off-wrist exposure produced multi-day gains in low-power modes, while on-wrist GPS workouts typically showed only a near‑wash versus normal battery draw.

How Amazfit built a two‑panel AMOLED solar watch

Amazfit started from the T‑Rex Ultra 2 feature set but reworked the hardware to add two distinct solar collectors and a smaller battery. The Dual Solar ships with a 660mAh battery where the Ultra 2 uses 870mAh, and the display is reduced to 1.3″ from 1.5″ to accommodate a solar ring. The rear panel is integrated around the optical heart‑rate module and is intended to be used off‑wrist — for example when you take a long break during an all‑day adventure and can face the caseback toward the sun. Amazfit says the rear panel area and its energy contribution are roughly double the front ring.

To support the rear usage the company moved the charging connector to the side and changed its pin design, a compatibility trade‑off for owners of older Amazfit accessories. Software supports an automatic Solar Boost mode that activates when the rear panel detects sun; users can also force Solar Boost or Battery Saver from settings. The watch can even boot from 0% using only solar if left exposed long enough, though in practice overheating and panel selection software matter more to what you actually gain.

Measured real‑world solar gains and limits

Ray Maker’s hands‑on tests found solar useful only in narrow scenarios. When left off the wrist in bright sun, the Dual Solar produced gains reported as multi‑day equivalents: examples include 2.8 days added in Smartwatch mode, 8.4 days in Battery Saver mode and 14.0 days in Watch‑only mode on a day of exposure. Those figures are what the watch reports as time added, not raw watt‑hours.

By contrast, wearing the watch while actively using sensors and GPS erased most of that headroom. During several workouts the measured battery draw was about a 2% loss per hour in typical GPS modes with gesture display, and in some rides the solar panels contributed almost nothing. One long outdoor test showed zero solar charging for the duration of the ride — Amazfit is investigating whether the automatic panel‑selection logic sometimes activates the rear panel while it is against the wrist, which would block collection.

Interface, diagnostics and overheating behaviour

Where Amazfit stands out is the visibility it gives to solar input. The Solar widget shows the last four‑hour graph with separate colors for front and rear contributions, an instant inbound power readout, and a Solar Index that rates charging quality. The widget also breaks out estimated gains for Smartwatch, Battery Saver and Watch‑only modes and lets you change timeframe to 1, 7 or 30 days. Those choices and the companion app mirror provide more granular feedback than many competitors.

But practical use is constrained by heat. In warm ambient temperatures the rear, off‑wrist orientation overheats quickly — Ray reported shutdowns within roughly ten minutes in 27–32°C (80–90°F) conditions — which halts charging until the unit cools. In cooler alpine environments Amazfit expects better sustained gains, but that remains conditional on ambient temperature and whether the rear panel is actually unobstructed.

Trade‑offs: who benefits and where the design makes sense

The Dual Solar answers a specific request — an AMOLED solar watch — but it does so with trade‑offs. To fit two panels and their routing Amazfit reduced battery capacity to 660mAh and shrank the display; that combination, plus AMOLED power draw, means everyday worn battery life can be worse than a non‑solar model with a larger cell. The product is also $100 more than the equivalent T‑Rex Ultra 2, putting the cost premium squarely on innovation rather than on longer run times.

Practically, the Dual Solar is best for users who can reliably expose the caseback to sunlight during long low‑use periods (for example, a long midday stop while hiking) or who prioritize the AMOLED look and data‑rich solar readouts. For typical athletes who wear the watch while active and rely on GPS, the solar system often nets out as negligible because charging and consumption roughly offset each other.

The case for and against further refinement

The bottom line

The Amazfit T‑Rex Dual Solar is a deliberate experiment: it delivers an AMOLED watch with both a front solar ring and a rear solar panel, visible and detailed solar telemetry, and the novelty of off‑wrist charging. In practice the combination produces measurable but narrow benefits — multi‑day gains in low‑power, off‑wrist conditions and limited or negligible benefits during active, on‑wrist GPS use. Thermal limits and occasional panel‑selection software issues further constrain real‑world returns. For users who can reliably expose the caseback to sun and value the AMOLED and telemetry, the Dual Solar is intriguing; for athletes who wear their watch while training, the trade‑offs in battery size and price make the Ultra 2 or other larger‑cell models a stronger everyday choice.

What to watch

• Look for an Amazfit firmware update that addresses automatic solar‑panel selection and the ride‑time no‑charge reports; no date has been set.
• Look for an Amazfit notice or patch that reduces rear‑panel overheating or changes Solar Boost thermal thresholds; no date has been set.