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Matrix PowerWatch 2: This smartwatch might never need charging

A solar- and body heat-powered smartwatch that never needs to be charged sounds like the future of watches, and I'm here for it.

Scott Stein Editor at Large
I started with CNET reviewing laptops in 2009. Now I explore wearable tech, VR/AR, tablets, gaming and future/emerging trends in our changing world. Other obsessions include magic, immersive theater, puzzles, board games, cooking, improv and the New York Jets. My background includes an MFA in theater which I apply to thinking about immersive experiences of the future.
Expertise VR and AR | Gaming | Metaverse technologies | Wearable tech | Tablets Credentials
  • Nearly 20 years writing about tech, and over a decade reviewing wearable tech, VR, and AR products and apps
Scott Stein
3 min read

The Matrix PowerWatch 2 is the sequel to a watch I wore a couple of years ago made by Matrix Industries, a thermoelectrics startup in Menlo Park whose headquarters I visited last year. The original PowerWatch worked, but wasn't great. This version, which I first got a peek at nearly a year ago, feels a lot better. It's finally close to being an everyday watch I'd use as a casual smartwatch.

Matrix PowerWatch 2


  • Battery lasts forever
  • Always-on display
  • Has basic fitness functions and notifications

Don't like

  • Button-based interface is confusing
  • Phone app and syncing are buggy
  • Watch will be too large for some
  • Features are limited compared to other smartwatches

It looks like a big old Casio G-Shock on my wrist. But it buzzes. A message pops up. I check it, and my step count, and my heart rate. Basic fitness stuff. I'd say it wasn't notable, except the Matrix PowerWatch 2 has been on my wrist for nearly a week and never lost any battery life. And, if all goes according to plan, I'll never, ever need to charge it.

It's a smartwatch powered by solar energy and your body heat

It's still far from the best smartwatch I've ever worn, but I don't think co-founders Douglas Tham and Akram Boukai are aiming for that claim. It's the way this watch never needs charging that's the amazing part. The watch's power recharging can be monitored in the phone app, where daily counts of thermal and solar energy can be graphed (I seemed to generate 170 microwatt-hours one day, while solar power generated another 310 microwatt-hours).

Matrix PowerWatch 2 doesn't need to be charged at all

See all photos

What can this smartwatch do?

The first Matrix watch could do basically just steps and tell time. The PowerWatch 2 has fitness tracking with GPS, notifications, steps, sleep , calorie count and heart rate. After a week of wearing it, so far so good. I get notifications that buzz to my wrist, but sometimes they're hard to read on the reflective, always-on color display because I have to scroll using side buttons instead of a touchscreen.

The PowerWatch 2 syncs with Apple Health and Google Fit, but the rest of the app's data is bare-bones: steps, calories burned, sleep (which isn't as detailed or as helpful as Fitbit's Sleep Score app) and daily energy-generated info.

Matrix Powerwatch 2

A side view of the watch: It's thick.

Sarah Tew/CNET

There aren't multiple watch faces to choose from, but the basic watch face is clear and crisp, especially in bright sunlight. I can see steps, heart rate (taken at intervals, not continuously) and start a workout, but the watch's GPS signal isn't acquiring very quickly. GPS might be the watch's Achilles heel. Matrix suggests only 30 minutes of GPS use a day before battery life starts to drain. A Micro USB-charging dongle is included in case GPS taps battery faster than the PowerWatch can recharge.

I don't use GPS much in my daily life, though. What bothers me more is that notifications sometimes don't appear on the watch -- I just get buzzes. And syncing via Bluetooth on an iPhone 11 Pro , is hit-and-miss so far.

The controls are clunky, too. Navigation happens with four buttons -- no touch. But still, I've been wearing the PowerWatch 2 nonstop, and it's growing on me. Its thick design isn't weird, and as an everyday watch, it's totally usable. The basic stat readouts are fine. Again, in general, it works.


A look at the watch on wrist, outdoors. Sharp display, but the recessed crystal collected some dust.

Scott Stein/CNET

The PowerWatch 2's price is... pretty high

Of course, for a "totally usable" watch, $500 isn't anyone's idea of a must-have, but then if you're thinking that way, you're missing the point. (The $499 Standard Edition and $599 Premium Edition both have aluminum cases with slightly different finishes and sapphire crystal-covered displays, but the Premium has a stainless steel watch strap instead of black silicone. I'm wearing the black silicone strap, and it feels extremely comfortable.)

It's the future hidden inside that's stunning. If the second-generation PowerWatch can already do this much, how long will it be until more everyday smartwatches are powered by solar, body heat or maybe kinetics? I do feel like I want to go back to an easier-to-use, more deeply-connected smartwatch. If the PowerWatch was just a bit better, if it was smaller, if the price was lower -- I might never go back. One week in, I love never having to charge my watch. This is the way things should be.