Amazfit T-Rex Dual Solar leak reveals a clever Solar Boost Mode

Zepp Health’s upcoming T-Rex Dual Solar has left another big clue inside the Zepp app, and this time we are learning something about how the watch may actually work. The latest version introduces a substantial solar software package, including a previously unseen Solar Boost Mode that strips the watch back to basic functions to improve charging efficiency.

We compared Zepp version 10.7.3 against the previous release, looking specifically for new device names and hardware-related code. There is plenty of routine stuff in the update, but the solar additions stand out.

T-Rex Dual Solar now appears by name

The first change is fairly straightforward. Zepp 10.7.3 now contains the full product name Amazfit T-Rex Dual Solar in its device resources. This is a first.

At this point the name itself is not a huge surprise. Regulatory filings have already connected model A2570 with the T-Rex Dual Solar, following appearances in several certification databases. But it is useful confirmation that Zepp Health is now adding the watch to the software it will use when the device reaches customers.

This also builds on something we spotted in the Zepp app last month. Back then the code contained references to solar intensity, watch_face_input_power and case_back_input_power, but there was no device name connecting those features to an actual Amazfit watch.

Solar Boost Mode is the interesting bit

The bigger discovery, this time around, is an entirely new solar software package in Zepp 10.7.3. It includes code for solar statistics, intensity readings, charging records and notifications, along with a dedicated solar education graphic.

Among the new components are SolarStatsActivity, SolarIntensityServiceImpl, SolarIntensityDataHandler and SolarBatteryChargeRemotePlugin. There are also references to solar intensity measured in kLux and the same separate watch-face and case-back input measurements we saw previously.

But one feature stands out above the rest. Zepp 10.7.3 introduces something called Solar Boost Mode.

The app explains that when the watch enters this mode, it will only display the time, battery level and solar intensity information. Most other functionality becomes unavailable, including data synchronisation, route transfer, workouts started through the app and some Zepp Coach features.

There are also warning messages for situations where charging efficiency is low and prompts telling the user that data cannot be synchronised while Solar Boost Mode is active.

That gives us a much better idea of what Zepp Health is trying to achieve.

Rather than simply placing a solar panel on the watch and allowing it to trickle-charge during normal use, Solar Boost Mode appears to slash power consumption so the energy coming in from the solar system has a better chance of increasing the battery level. In other words, you may be able to put the watch into a deliberately restricted state when extending battery life is more important than using its smart features.

For a T-Rex device aimed at hiking, expeditions and long periods away from a charger, that makes quite a lot of sense.

It could also make Amazfit’s implementation rather different from the typical solar-assisted smartwatch. Garmin solar watches, for example, generally use sunlight to extend battery life while the watch continues operating normally. A dedicated low-power solar charging mode could give Zepp Health another way of squeezing useful energy from a relatively small solar surface.

There is still plenty we do not know. The code does not tell us how quickly the T-Rex Dual Solar charges or how much extra battery life it can generate.

The earlier watch_face_input_power and case_back_input_power fields remain particularly intriguing. They could point to two separate energy inputs, but at this stage we can’t draw a firm conclusion from those names alone.

The hardware has still not been announced, but the software side is starting to look very close to finished. Zepp Health now has the T-Rex Dual Solar name in the app, a solar statistics interface, charging records, intensity measurements and an entire Solar Boost Mode ready to manage the watch when solar charging becomes the priority.