If a Fitbit could completely be self-powered and never needed charging, I'd be a happy person. Matrix Industries' latest fitness watch looks like the closest anyone's ever come to making that happen.

And it looks pretty good on my wrist.

The Matrix PowerWatch 2, launching at CES 2019, seems to have all the features I'd want: heart rate, step counting, an always-on reflective color screen, 200 meter water resistance, notifications and GPS that the company claims lasts as long as a marathon. And it runs completely off solar power and body-generated heat.

Matrix has already made several no-charge-necessary fitness watches, but its previous Matrix PowerWatch could only track steps and tell time. It was an impressive feat, but the watch's functions felt too limited.

This time, added solar charging along with thermoelectrics allow the watch to gain a larger smartwatch feature set that seems to challenge the Fitbits and Garmins of the world.

I tried the PowerWatch 2 on my wrist at the company's headquarters in Menlo Park, California, where I met with Matrix Industries co-founders CEO Akram Boukai and CTO Douglas Tham.

The PowerWatch 2 is less bulky than the last version and will come in a wider variety of color and strap combinations than the original, which had a mostly black look. It still looks like a hardcore outdoor-type watch in the spirit of the Casio G-Shock, and has the same 1.2-inch display and weight. But it loses some of the metal grilles that were on the previous model (it's a 42mm watch now, versus the previous 50mm design) and adds extra buttons while losing the turning crown. There's a new reflective solar ring around the watch display, too, which adds a bit of flair. A new always-on color reflective display looks crisp in direct light, similar to the Amazfit Bip, or the long-departed Pebble Time.

The PowerWatch 2 works with Apple HealthKit and Google Fit. It can also connect with additional (but as yet unnamed) third-party fitness apps. According to Tham and Boukai, notifications will pop up like on other smartwatches, too.

Matrix is using a newer Ambiq Apollo 3 processor onboard compared to previous PowerWatches. There's also a compass, plus heart-rate monitoring and GPS. Matrix claims the PowerWatch 2's continuous heart rate and GPS tracking could even last through a marathon. The watch will also have some social fitness functions, inviting wearers to compete based on calories burned. (The original PowerWatch, since it literally converted heat to electricity, could measure calories burned as well.)

Along with Matrix's efforts to create heat-powered IoT smart beacons and sensors, the new watch is blending another power source to explore how the company can power more advanced electronics. Matrix considered its original watch more of a living tech demo, showing how the company's thermal gradient-powered electronics could drive low-powered devices. The new PowerWatch 2 could, in a similar way, be showcasing how solar plus thermoelectrics could be used not just in watches, but in next-wave smart home and IoT sensors or other wearables.

The PowerWatch 2 still doesn't support any music playback, and doesn't have a music remote. But Matrix might be considering hearables, if its tech can support powering low-power headphones or hearing aids.

Matrix aims to adopt solar, but also other energy sources in the future, all in the service of getting to more advanced gadgets. Could kinetic be next? "That's a PowerWatch 3 feature," Tham half-jokes. 

But, maybe it's a sign of where the next wave of fitness-meets-traditional watches is headed. "You may see Matrix-powered technology in other brand name devices," Matrix's representatives said to me when I toured the company's headquarters, without giving specific names or brands, but suggesting that 2019 might not be out of the question. 

The company uses its PowerWatch models as testbeds to explore how its energy-harvesting tech works, making these watches concept cars of a sort. But the company says it's also trying to keep its loyal customer base happy. Certainly, being able to cast off batteries or charging from traditional-style fitness watches is something I'd love to see.

Read more: Here comes the thermoelectric future

Or maybe, if the PowerWatch 2 can work without charging, then what about making other fitness-sensor devices worn across the body that could measure specific movement or data and interlink, all charge-free? "That's definitely something that could be done," says Tham.

The Matrix PowerWatch 2 can be preordered from today on Indiegogo for $200 (about £160 or AU$280) and will cost $499 when it's available later this year. 

As always, please note that CNET's reporting on crowdfunding campaigns is not an endorsement of the project or its creators. Before contributing to any campaign, read the crowdfunding site's policies -- in this case, Indiegogo -- to find out your rights (and refund policies, or the lack thereof) before and after a campaign ends.

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